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Date: Wed, 22 Jun 2011 10:13:41 -0400
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To: dexen deVries <dexen.devries@...il.com>, dan.magenheimer@...cle.com
Cc: linux-kernel@...r.kernel.org,
Linus Torvalds <torvalds@...ux-foundation.org>,
Nitin Gupta <ngupta@...are.org>
Subject: Re: [PATCH] zcache: rename zcache.c to avoid build problem
On Wed, Jun 22, 2011 at 10:26:29AM +0200, dexen deVries wrote:
> zcache.c was not being compiled as its target filename
> was the same as overall name of module to be built.
Hmm, Dan?
>
> Signed-off-by: dexen deVries <dexen.devries@...il.com>
> ---
> drivers/staging/zcache/Makefile | 2 +-
> drivers/staging/zcache/zcache.c | 1661 -----------------------------------
> drivers/staging/zcache/zcache_drv.c | 1661 +++++++++++++++++++++++++++++++++++
> 3 files changed, 1662 insertions(+), 1662 deletions(-)
> delete mode 100644 drivers/staging/zcache/zcache.c
> create mode 100644 drivers/staging/zcache/zcache_drv.c
>
> diff --git a/drivers/staging/zcache/Makefile b/drivers/staging/zcache/Makefile
> index f5ec64f..e3c945f 100644
> --- a/drivers/staging/zcache/Makefile
> +++ b/drivers/staging/zcache/Makefile
> @@ -1,3 +1,3 @@
> -zcache-y := tmem.o
> +zcache-y := zcache_drv.o tmem.o
>
> obj-$(CONFIG_ZCACHE) += zcache.o
> diff --git a/drivers/staging/zcache/zcache.c b/drivers/staging/zcache/zcache.c
> deleted file mode 100644
> index 77ac2d4..0000000
> --- a/drivers/staging/zcache/zcache.c
> +++ /dev/null
> @@ -1,1661 +0,0 @@
> -/*
> - * zcache.c
> - *
> - * Copyright (c) 2010,2011, Dan Magenheimer, Oracle Corp.
> - * Copyright (c) 2010,2011, Nitin Gupta
> - *
> - * Zcache provides an in-kernel "host implementation" for transcendent memory
> - * and, thus indirectly, for cleancache and frontswap. Zcache includes two
> - * page-accessible memory [1] interfaces, both utilizing lzo1x compression:
> - * 1) "compression buddies" ("zbud") is used for ephemeral pages
> - * 2) xvmalloc is used for persistent pages.
> - * Xvmalloc (based on the TLSF allocator) has very low fragmentation
> - * so maximizes space efficiency, while zbud allows pairs (and potentially,
> - * in the future, more than a pair of) compressed pages to be closely linked
> - * so that reclaiming can be done via the kernel's physical-page-oriented
> - * "shrinker" interface.
> - *
> - * [1] For a definition of page-accessible memory (aka PAM), see:
> - * http://marc.info/?l=linux-mm&m=127811271605009
> - */
> -
> -#include <linux/cpu.h>
> -#include <linux/highmem.h>
> -#include <linux/list.h>
> -#include <linux/lzo.h>
> -#include <linux/slab.h>
> -#include <linux/spinlock.h>
> -#include <linux/types.h>
> -#include <linux/atomic.h>
> -#include "tmem.h"
> -
> -#include "../zram/xvmalloc.h" /* if built in drivers/staging */
> -
> -#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP))
> -#error "zcache is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP"
> -#endif
> -#ifdef CONFIG_CLEANCACHE
> -#include <linux/cleancache.h>
> -#endif
> -#ifdef CONFIG_FRONTSWAP
> -#include <linux/frontswap.h>
> -#endif
> -
> -#if 0
> -/* this is more aggressive but may cause other problems? */
> -#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN)
> -#else
> -#define ZCACHE_GFP_MASK \
> - (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
> -#endif
> -
> -/**********
> - * Compression buddies ("zbud") provides for packing two (or, possibly
> - * in the future, more) compressed ephemeral pages into a single "raw"
> - * (physical) page and tracking them with data structures so that
> - * the raw pages can be easily reclaimed.
> - *
> - * A zbud page ("zbpg") is an aligned page containing a list_head,
> - * a lock, and two "zbud headers". The remainder of the physical
> - * page is divided up into aligned 64-byte "chunks" which contain
> - * the compressed data for zero, one, or two zbuds. Each zbpg
> - * resides on: (1) an "unused list" if it has no zbuds; (2) a
> - * "buddied" list if it is fully populated with two zbuds; or
> - * (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks
> - * the one unbuddied zbud uses. The data inside a zbpg cannot be
> - * read or written unless the zbpg's lock is held.
> - */
> -
> -#define ZBH_SENTINEL 0x43214321
> -#define ZBPG_SENTINEL 0xdeadbeef
> -
> -#define ZBUD_MAX_BUDS 2
> -
> -struct zbud_hdr {
> - uint32_t pool_id;
> - struct tmem_oid oid;
> - uint32_t index;
> - uint16_t size; /* compressed size in bytes, zero means unused */
> - DECL_SENTINEL
> -};
> -
> -struct zbud_page {
> - struct list_head bud_list;
> - spinlock_t lock;
> - struct zbud_hdr buddy[ZBUD_MAX_BUDS];
> - DECL_SENTINEL
> - /* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */
> -};
> -
> -#define CHUNK_SHIFT 6
> -#define CHUNK_SIZE (1 << CHUNK_SHIFT)
> -#define CHUNK_MASK (~(CHUNK_SIZE-1))
> -#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \
> - CHUNK_MASK) >> CHUNK_SHIFT)
> -#define MAX_CHUNK (NCHUNKS-1)
> -
> -static struct {
> - struct list_head list;
> - unsigned count;
> -} zbud_unbuddied[NCHUNKS];
> -/* list N contains pages with N chunks USED and NCHUNKS-N unused */
> -/* element 0 is never used but optimizing that isn't worth it */
> -static unsigned long zbud_cumul_chunk_counts[NCHUNKS];
> -
> -struct list_head zbud_buddied_list;
> -static unsigned long zcache_zbud_buddied_count;
> -
> -/* protects the buddied list and all unbuddied lists */
> -static DEFINE_SPINLOCK(zbud_budlists_spinlock);
> -
> -static LIST_HEAD(zbpg_unused_list);
> -static unsigned long zcache_zbpg_unused_list_count;
> -
> -/* protects the unused page list */
> -static DEFINE_SPINLOCK(zbpg_unused_list_spinlock);
> -
> -static atomic_t zcache_zbud_curr_raw_pages;
> -static atomic_t zcache_zbud_curr_zpages;
> -static unsigned long zcache_zbud_curr_zbytes;
> -static unsigned long zcache_zbud_cumul_zpages;
> -static unsigned long zcache_zbud_cumul_zbytes;
> -static unsigned long zcache_compress_poor;
> -
> -/* forward references */
> -static void *zcache_get_free_page(void);
> -static void zcache_free_page(void *p);
> -
> -/*
> - * zbud helper functions
> - */
> -
> -static inline unsigned zbud_max_buddy_size(void)
> -{
> - return MAX_CHUNK << CHUNK_SHIFT;
> -}
> -
> -static inline unsigned zbud_size_to_chunks(unsigned size)
> -{
> - BUG_ON(size == 0 || size > zbud_max_buddy_size());
> - return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
> -}
> -
> -static inline int zbud_budnum(struct zbud_hdr *zh)
> -{
> - unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1);
> - struct zbud_page *zbpg = NULL;
> - unsigned budnum = -1U;
> - int i;
> -
> - for (i = 0; i < ZBUD_MAX_BUDS; i++)
> - if (offset == offsetof(typeof(*zbpg), buddy[i])) {
> - budnum = i;
> - break;
> - }
> - BUG_ON(budnum == -1U);
> - return budnum;
> -}
> -
> -static char *zbud_data(struct zbud_hdr *zh, unsigned size)
> -{
> - struct zbud_page *zbpg;
> - char *p;
> - unsigned budnum;
> -
> - ASSERT_SENTINEL(zh, ZBH);
> - budnum = zbud_budnum(zh);
> - BUG_ON(size == 0 || size > zbud_max_buddy_size());
> - zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
> - ASSERT_SPINLOCK(&zbpg->lock);
> - p = (char *)zbpg;
> - if (budnum == 0)
> - p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
> - CHUNK_MASK);
> - else if (budnum == 1)
> - p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
> - return p;
> -}
> -
> -/*
> - * zbud raw page management
> - */
> -
> -static struct zbud_page *zbud_alloc_raw_page(void)
> -{
> - struct zbud_page *zbpg = NULL;
> - struct zbud_hdr *zh0, *zh1;
> - bool recycled = 0;
> -
> - /* if any pages on the zbpg list, use one */
> - spin_lock(&zbpg_unused_list_spinlock);
> - if (!list_empty(&zbpg_unused_list)) {
> - zbpg = list_first_entry(&zbpg_unused_list,
> - struct zbud_page, bud_list);
> - list_del_init(&zbpg->bud_list);
> - zcache_zbpg_unused_list_count--;
> - recycled = 1;
> - }
> - spin_unlock(&zbpg_unused_list_spinlock);
> - if (zbpg == NULL)
> - /* none on zbpg list, try to get a kernel page */
> - zbpg = zcache_get_free_page();
> - if (likely(zbpg != NULL)) {
> - INIT_LIST_HEAD(&zbpg->bud_list);
> - zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
> - spin_lock_init(&zbpg->lock);
> - if (recycled) {
> - ASSERT_INVERTED_SENTINEL(zbpg, ZBPG);
> - SET_SENTINEL(zbpg, ZBPG);
> - BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
> - BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
> - } else {
> - atomic_inc(&zcache_zbud_curr_raw_pages);
> - INIT_LIST_HEAD(&zbpg->bud_list);
> - SET_SENTINEL(zbpg, ZBPG);
> - zh0->size = 0; zh1->size = 0;
> - tmem_oid_set_invalid(&zh0->oid);
> - tmem_oid_set_invalid(&zh1->oid);
> - }
> - }
> - return zbpg;
> -}
> -
> -static void zbud_free_raw_page(struct zbud_page *zbpg)
> -{
> - struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1];
> -
> - ASSERT_SENTINEL(zbpg, ZBPG);
> - BUG_ON(!list_empty(&zbpg->bud_list));
> - ASSERT_SPINLOCK(&zbpg->lock);
> - BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
> - BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
> - INVERT_SENTINEL(zbpg, ZBPG);
> - spin_unlock(&zbpg->lock);
> - spin_lock(&zbpg_unused_list_spinlock);
> - list_add(&zbpg->bud_list, &zbpg_unused_list);
> - zcache_zbpg_unused_list_count++;
> - spin_unlock(&zbpg_unused_list_spinlock);
> -}
> -
> -/*
> - * core zbud handling routines
> - */
> -
> -static unsigned zbud_free(struct zbud_hdr *zh)
> -{
> - unsigned size;
> -
> - ASSERT_SENTINEL(zh, ZBH);
> - BUG_ON(!tmem_oid_valid(&zh->oid));
> - size = zh->size;
> - BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
> - zh->size = 0;
> - tmem_oid_set_invalid(&zh->oid);
> - INVERT_SENTINEL(zh, ZBH);
> - zcache_zbud_curr_zbytes -= size;
> - atomic_dec(&zcache_zbud_curr_zpages);
> - return size;
> -}
> -
> -static void zbud_free_and_delist(struct zbud_hdr *zh)
> -{
> - unsigned chunks;
> - struct zbud_hdr *zh_other;
> - unsigned budnum = zbud_budnum(zh), size;
> - struct zbud_page *zbpg =
> - container_of(zh, struct zbud_page, buddy[budnum]);
> -
> - spin_lock(&zbpg->lock);
> - if (list_empty(&zbpg->bud_list)) {
> - /* ignore zombie page... see zbud_evict_pages() */
> - spin_unlock(&zbpg->lock);
> - return;
> - }
> - size = zbud_free(zh);
> - ASSERT_SPINLOCK(&zbpg->lock);
> - zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0];
> - if (zh_other->size == 0) { /* was unbuddied: unlist and free */
> - chunks = zbud_size_to_chunks(size) ;
> - spin_lock(&zbud_budlists_spinlock);
> - BUG_ON(list_empty(&zbud_unbuddied[chunks].list));
> - list_del_init(&zbpg->bud_list);
> - zbud_unbuddied[chunks].count--;
> - spin_unlock(&zbud_budlists_spinlock);
> - zbud_free_raw_page(zbpg);
> - } else { /* was buddied: move remaining buddy to unbuddied list */
> - chunks = zbud_size_to_chunks(zh_other->size) ;
> - spin_lock(&zbud_budlists_spinlock);
> - list_del_init(&zbpg->bud_list);
> - zcache_zbud_buddied_count--;
> - list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list);
> - zbud_unbuddied[chunks].count++;
> - spin_unlock(&zbud_budlists_spinlock);
> - spin_unlock(&zbpg->lock);
> - }
> -}
> -
> -static struct zbud_hdr *zbud_create(uint32_t pool_id, struct tmem_oid *oid,
> - uint32_t index, struct page *page,
> - void *cdata, unsigned size)
> -{
> - struct zbud_hdr *zh0, *zh1, *zh = NULL;
> - struct zbud_page *zbpg = NULL, *ztmp;
> - unsigned nchunks;
> - char *to;
> - int i, found_good_buddy = 0;
> -
> - nchunks = zbud_size_to_chunks(size) ;
> - for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) {
> - spin_lock(&zbud_budlists_spinlock);
> - if (!list_empty(&zbud_unbuddied[i].list)) {
> - list_for_each_entry_safe(zbpg, ztmp,
> - &zbud_unbuddied[i].list, bud_list) {
> - if (spin_trylock(&zbpg->lock)) {
> - found_good_buddy = i;
> - goto found_unbuddied;
> - }
> - }
> - }
> - spin_unlock(&zbud_budlists_spinlock);
> - }
> - /* didn't find a good buddy, try allocating a new page */
> - zbpg = zbud_alloc_raw_page();
> - if (unlikely(zbpg == NULL))
> - goto out;
> - /* ok, have a page, now compress the data before taking locks */
> - spin_lock(&zbpg->lock);
> - spin_lock(&zbud_budlists_spinlock);
> - list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list);
> - zbud_unbuddied[nchunks].count++;
> - zh = &zbpg->buddy[0];
> - goto init_zh;
> -
> -found_unbuddied:
> - ASSERT_SPINLOCK(&zbpg->lock);
> - zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
> - BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0)));
> - if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */
> - ASSERT_SENTINEL(zh0, ZBH);
> - zh = zh1;
> - } else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */
> - ASSERT_SENTINEL(zh1, ZBH);
> - zh = zh0;
> - } else
> - BUG();
> - list_del_init(&zbpg->bud_list);
> - zbud_unbuddied[found_good_buddy].count--;
> - list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
> - zcache_zbud_buddied_count++;
> -
> -init_zh:
> - SET_SENTINEL(zh, ZBH);
> - zh->size = size;
> - zh->index = index;
> - zh->oid = *oid;
> - zh->pool_id = pool_id;
> - /* can wait to copy the data until the list locks are dropped */
> - spin_unlock(&zbud_budlists_spinlock);
> -
> - to = zbud_data(zh, size);
> - memcpy(to, cdata, size);
> - spin_unlock(&zbpg->lock);
> - zbud_cumul_chunk_counts[nchunks]++;
> - atomic_inc(&zcache_zbud_curr_zpages);
> - zcache_zbud_cumul_zpages++;
> - zcache_zbud_curr_zbytes += size;
> - zcache_zbud_cumul_zbytes += size;
> -out:
> - return zh;
> -}
> -
> -static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
> -{
> - struct zbud_page *zbpg;
> - unsigned budnum = zbud_budnum(zh);
> - size_t out_len = PAGE_SIZE;
> - char *to_va, *from_va;
> - unsigned size;
> - int ret = 0;
> -
> - zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
> - spin_lock(&zbpg->lock);
> - if (list_empty(&zbpg->bud_list)) {
> - /* ignore zombie page... see zbud_evict_pages() */
> - ret = -EINVAL;
> - goto out;
> - }
> - ASSERT_SENTINEL(zh, ZBH);
> - BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
> - to_va = kmap_atomic(page, KM_USER0);
> - size = zh->size;
> - from_va = zbud_data(zh, size);
> - ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len);
> - BUG_ON(ret != LZO_E_OK);
> - BUG_ON(out_len != PAGE_SIZE);
> - kunmap_atomic(to_va, KM_USER0);
> -out:
> - spin_unlock(&zbpg->lock);
> - return ret;
> -}
> -
> -/*
> - * The following routines handle shrinking of ephemeral pages by evicting
> - * pages "least valuable" first.
> - */
> -
> -static unsigned long zcache_evicted_raw_pages;
> -static unsigned long zcache_evicted_buddied_pages;
> -static unsigned long zcache_evicted_unbuddied_pages;
> -
> -static struct tmem_pool *zcache_get_pool_by_id(uint32_t poolid);
> -static void zcache_put_pool(struct tmem_pool *pool);
> -
> -/*
> - * Flush and free all zbuds in a zbpg, then free the pageframe
> - */
> -static void zbud_evict_zbpg(struct zbud_page *zbpg)
> -{
> - struct zbud_hdr *zh;
> - int i, j;
> - uint32_t pool_id[ZBUD_MAX_BUDS], index[ZBUD_MAX_BUDS];
> - struct tmem_oid oid[ZBUD_MAX_BUDS];
> - struct tmem_pool *pool;
> -
> - ASSERT_SPINLOCK(&zbpg->lock);
> - BUG_ON(!list_empty(&zbpg->bud_list));
> - for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) {
> - zh = &zbpg->buddy[i];
> - if (zh->size) {
> - pool_id[j] = zh->pool_id;
> - oid[j] = zh->oid;
> - index[j] = zh->index;
> - j++;
> - zbud_free(zh);
> - }
> - }
> - spin_unlock(&zbpg->lock);
> - for (i = 0; i < j; i++) {
> - pool = zcache_get_pool_by_id(pool_id[i]);
> - if (pool != NULL) {
> - tmem_flush_page(pool, &oid[i], index[i]);
> - zcache_put_pool(pool);
> - }
> - }
> - ASSERT_SENTINEL(zbpg, ZBPG);
> - spin_lock(&zbpg->lock);
> - zbud_free_raw_page(zbpg);
> -}
> -
> -/*
> - * Free nr pages. This code is funky because we want to hold the locks
> - * protecting various lists for as short a time as possible, and in some
> - * circumstances the list may change asynchronously when the list lock is
> - * not held. In some cases we also trylock not only to avoid waiting on a
> - * page in use by another cpu, but also to avoid potential deadlock due to
> - * lock inversion.
> - */
> -static void zbud_evict_pages(int nr)
> -{
> - struct zbud_page *zbpg;
> - int i;
> -
> - /* first try freeing any pages on unused list */
> -retry_unused_list:
> - spin_lock_bh(&zbpg_unused_list_spinlock);
> - if (!list_empty(&zbpg_unused_list)) {
> - /* can't walk list here, since it may change when unlocked */
> - zbpg = list_first_entry(&zbpg_unused_list,
> - struct zbud_page, bud_list);
> - list_del_init(&zbpg->bud_list);
> - zcache_zbpg_unused_list_count--;
> - atomic_dec(&zcache_zbud_curr_raw_pages);
> - spin_unlock_bh(&zbpg_unused_list_spinlock);
> - zcache_free_page(zbpg);
> - zcache_evicted_raw_pages++;
> - if (--nr <= 0)
> - goto out;
> - goto retry_unused_list;
> - }
> - spin_unlock_bh(&zbpg_unused_list_spinlock);
> -
> - /* now try freeing unbuddied pages, starting with least space avail */
> - for (i = 0; i < MAX_CHUNK; i++) {
> -retry_unbud_list_i:
> - spin_lock_bh(&zbud_budlists_spinlock);
> - if (list_empty(&zbud_unbuddied[i].list)) {
> - spin_unlock_bh(&zbud_budlists_spinlock);
> - continue;
> - }
> - list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
> - if (unlikely(!spin_trylock(&zbpg->lock)))
> - continue;
> - list_del_init(&zbpg->bud_list);
> - zbud_unbuddied[i].count--;
> - spin_unlock(&zbud_budlists_spinlock);
> - zcache_evicted_unbuddied_pages++;
> - /* want budlists unlocked when doing zbpg eviction */
> - zbud_evict_zbpg(zbpg);
> - local_bh_enable();
> - if (--nr <= 0)
> - goto out;
> - goto retry_unbud_list_i;
> - }
> - spin_unlock_bh(&zbud_budlists_spinlock);
> - }
> -
> - /* as a last resort, free buddied pages */
> -retry_bud_list:
> - spin_lock_bh(&zbud_budlists_spinlock);
> - if (list_empty(&zbud_buddied_list)) {
> - spin_unlock_bh(&zbud_budlists_spinlock);
> - goto out;
> - }
> - list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
> - if (unlikely(!spin_trylock(&zbpg->lock)))
> - continue;
> - list_del_init(&zbpg->bud_list);
> - zcache_zbud_buddied_count--;
> - spin_unlock(&zbud_budlists_spinlock);
> - zcache_evicted_buddied_pages++;
> - /* want budlists unlocked when doing zbpg eviction */
> - zbud_evict_zbpg(zbpg);
> - local_bh_enable();
> - if (--nr <= 0)
> - goto out;
> - goto retry_bud_list;
> - }
> - spin_unlock_bh(&zbud_budlists_spinlock);
> -out:
> - return;
> -}
> -
> -static void zbud_init(void)
> -{
> - int i;
> -
> - INIT_LIST_HEAD(&zbud_buddied_list);
> - zcache_zbud_buddied_count = 0;
> - for (i = 0; i < NCHUNKS; i++) {
> - INIT_LIST_HEAD(&zbud_unbuddied[i].list);
> - zbud_unbuddied[i].count = 0;
> - }
> -}
> -
> -#ifdef CONFIG_SYSFS
> -/*
> - * These sysfs routines show a nice distribution of how many zbpg's are
> - * currently (and have ever been placed) in each unbuddied list. It's fun
> - * to watch but can probably go away before final merge.
> - */
> -static int zbud_show_unbuddied_list_counts(char *buf)
> -{
> - int i;
> - char *p = buf;
> -
> - for (i = 0; i < NCHUNKS - 1; i++)
> - p += sprintf(p, "%u ", zbud_unbuddied[i].count);
> - p += sprintf(p, "%d\n", zbud_unbuddied[i].count);
> - return p - buf;
> -}
> -
> -static int zbud_show_cumul_chunk_counts(char *buf)
> -{
> - unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0;
> - unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0;
> - unsigned long total_chunks_lte_42 = 0;
> - char *p = buf;
> -
> - for (i = 0; i < NCHUNKS; i++) {
> - p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]);
> - chunks += zbud_cumul_chunk_counts[i];
> - total_chunks += zbud_cumul_chunk_counts[i];
> - sum_total_chunks += i * zbud_cumul_chunk_counts[i];
> - if (i == 21)
> - total_chunks_lte_21 = total_chunks;
> - if (i == 32)
> - total_chunks_lte_32 = total_chunks;
> - if (i == 42)
> - total_chunks_lte_42 = total_chunks;
> - }
> - p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n",
> - total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42,
> - chunks == 0 ? 0 : sum_total_chunks / chunks);
> - return p - buf;
> -}
> -#endif
> -
> -/**********
> - * This "zv" PAM implementation combines the TLSF-based xvMalloc
> - * with lzo1x compression to maximize the amount of data that can
> - * be packed into a physical page.
> - *
> - * Zv represents a PAM page with the index and object (plus a "size" value
> - * necessary for decompression) immediately preceding the compressed data.
> - */
> -
> -#define ZVH_SENTINEL 0x43214321
> -
> -struct zv_hdr {
> - uint32_t pool_id;
> - struct tmem_oid oid;
> - uint32_t index;
> - DECL_SENTINEL
> -};
> -
> -static const int zv_max_page_size = (PAGE_SIZE / 8) * 7;
> -
> -static struct zv_hdr *zv_create(struct xv_pool *xvpool, uint32_t pool_id,
> - struct tmem_oid *oid, uint32_t index,
> - void *cdata, unsigned clen)
> -{
> - struct page *page;
> - struct zv_hdr *zv = NULL;
> - uint32_t offset;
> - int ret;
> -
> - BUG_ON(!irqs_disabled());
> - ret = xv_malloc(xvpool, clen + sizeof(struct zv_hdr),
> - &page, &offset, ZCACHE_GFP_MASK);
> - if (unlikely(ret))
> - goto out;
> - zv = kmap_atomic(page, KM_USER0) + offset;
> - zv->index = index;
> - zv->oid = *oid;
> - zv->pool_id = pool_id;
> - SET_SENTINEL(zv, ZVH);
> - memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen);
> - kunmap_atomic(zv, KM_USER0);
> -out:
> - return zv;
> -}
> -
> -static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv)
> -{
> - unsigned long flags;
> - struct page *page;
> - uint32_t offset;
> - uint16_t size;
> -
> - ASSERT_SENTINEL(zv, ZVH);
> - size = xv_get_object_size(zv) - sizeof(*zv);
> - BUG_ON(size == 0 || size > zv_max_page_size);
> - INVERT_SENTINEL(zv, ZVH);
> - page = virt_to_page(zv);
> - offset = (unsigned long)zv & ~PAGE_MASK;
> - local_irq_save(flags);
> - xv_free(xvpool, page, offset);
> - local_irq_restore(flags);
> -}
> -
> -static void zv_decompress(struct page *page, struct zv_hdr *zv)
> -{
> - size_t clen = PAGE_SIZE;
> - char *to_va;
> - unsigned size;
> - int ret;
> -
> - ASSERT_SENTINEL(zv, ZVH);
> - size = xv_get_object_size(zv) - sizeof(*zv);
> - BUG_ON(size == 0 || size > zv_max_page_size);
> - to_va = kmap_atomic(page, KM_USER0);
> - ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv),
> - size, to_va, &clen);
> - kunmap_atomic(to_va, KM_USER0);
> - BUG_ON(ret != LZO_E_OK);
> - BUG_ON(clen != PAGE_SIZE);
> -}
> -
> -/*
> - * zcache core code starts here
> - */
> -
> -/* useful stats not collected by cleancache or frontswap */
> -static unsigned long zcache_flush_total;
> -static unsigned long zcache_flush_found;
> -static unsigned long zcache_flobj_total;
> -static unsigned long zcache_flobj_found;
> -static unsigned long zcache_failed_eph_puts;
> -static unsigned long zcache_failed_pers_puts;
> -
> -#define MAX_POOLS_PER_CLIENT 16
> -
> -static struct {
> - struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT];
> - struct xv_pool *xvpool;
> -} zcache_client;
> -
> -/*
> - * Tmem operations assume the poolid implies the invoking client.
> - * Zcache only has one client (the kernel itself), so translate
> - * the poolid into the tmem_pool allocated for it. A KVM version
> - * of zcache would have one client per guest and each client might
> - * have a poolid==N.
> - */
> -static struct tmem_pool *zcache_get_pool_by_id(uint32_t poolid)
> -{
> - struct tmem_pool *pool = NULL;
> -
> - if (poolid >= 0) {
> - pool = zcache_client.tmem_pools[poolid];
> - if (pool != NULL)
> - atomic_inc(&pool->refcount);
> - }
> - return pool;
> -}
> -
> -static void zcache_put_pool(struct tmem_pool *pool)
> -{
> - if (pool != NULL)
> - atomic_dec(&pool->refcount);
> -}
> -
> -/* counters for debugging */
> -static unsigned long zcache_failed_get_free_pages;
> -static unsigned long zcache_failed_alloc;
> -static unsigned long zcache_put_to_flush;
> -static unsigned long zcache_aborted_preload;
> -static unsigned long zcache_aborted_shrink;
> -
> -/*
> - * Ensure that memory allocation requests in zcache don't result
> - * in direct reclaim requests via the shrinker, which would cause
> - * an infinite loop. Maybe a GFP flag would be better?
> - */
> -static DEFINE_SPINLOCK(zcache_direct_reclaim_lock);
> -
> -/*
> - * for now, used named slabs so can easily track usage; later can
> - * either just use kmalloc, or perhaps add a slab-like allocator
> - * to more carefully manage total memory utilization
> - */
> -static struct kmem_cache *zcache_objnode_cache;
> -static struct kmem_cache *zcache_obj_cache;
> -static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0);
> -static unsigned long zcache_curr_obj_count_max;
> -static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0);
> -static unsigned long zcache_curr_objnode_count_max;
> -
> -/*
> - * to avoid memory allocation recursion (e.g. due to direct reclaim), we
> - * preload all necessary data structures so the hostops callbacks never
> - * actually do a malloc
> - */
> -struct zcache_preload {
> - void *page;
> - struct tmem_obj *obj;
> - int nr;
> - struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH];
> -};
> -static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
> -
> -static int zcache_do_preload(struct tmem_pool *pool)
> -{
> - struct zcache_preload *kp;
> - struct tmem_objnode *objnode;
> - struct tmem_obj *obj;
> - void *page;
> - int ret = -ENOMEM;
> -
> - if (unlikely(zcache_objnode_cache == NULL))
> - goto out;
> - if (unlikely(zcache_obj_cache == NULL))
> - goto out;
> - if (!spin_trylock(&zcache_direct_reclaim_lock)) {
> - zcache_aborted_preload++;
> - goto out;
> - }
> - preempt_disable();
> - kp = &__get_cpu_var(zcache_preloads);
> - while (kp->nr < ARRAY_SIZE(kp->objnodes)) {
> - preempt_enable_no_resched();
> - objnode = kmem_cache_alloc(zcache_objnode_cache,
> - ZCACHE_GFP_MASK);
> - if (unlikely(objnode == NULL)) {
> - zcache_failed_alloc++;
> - goto unlock_out;
> - }
> - preempt_disable();
> - kp = &__get_cpu_var(zcache_preloads);
> - if (kp->nr < ARRAY_SIZE(kp->objnodes))
> - kp->objnodes[kp->nr++] = objnode;
> - else
> - kmem_cache_free(zcache_objnode_cache, objnode);
> - }
> - preempt_enable_no_resched();
> - obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
> - if (unlikely(obj == NULL)) {
> - zcache_failed_alloc++;
> - goto unlock_out;
> - }
> - page = (void *)__get_free_page(ZCACHE_GFP_MASK);
> - if (unlikely(page == NULL)) {
> - zcache_failed_get_free_pages++;
> - kmem_cache_free(zcache_obj_cache, obj);
> - goto unlock_out;
> - }
> - preempt_disable();
> - kp = &__get_cpu_var(zcache_preloads);
> - if (kp->obj == NULL)
> - kp->obj = obj;
> - else
> - kmem_cache_free(zcache_obj_cache, obj);
> - if (kp->page == NULL)
> - kp->page = page;
> - else
> - free_page((unsigned long)page);
> - ret = 0;
> -unlock_out:
> - spin_unlock(&zcache_direct_reclaim_lock);
> -out:
> - return ret;
> -}
> -
> -static void *zcache_get_free_page(void)
> -{
> - struct zcache_preload *kp;
> - void *page;
> -
> - kp = &__get_cpu_var(zcache_preloads);
> - page = kp->page;
> - BUG_ON(page == NULL);
> - kp->page = NULL;
> - return page;
> -}
> -
> -static void zcache_free_page(void *p)
> -{
> - free_page((unsigned long)p);
> -}
> -
> -/*
> - * zcache implementation for tmem host ops
> - */
> -
> -static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
> -{
> - struct tmem_objnode *objnode = NULL;
> - unsigned long count;
> - struct zcache_preload *kp;
> -
> - kp = &__get_cpu_var(zcache_preloads);
> - if (kp->nr <= 0)
> - goto out;
> - objnode = kp->objnodes[kp->nr - 1];
> - BUG_ON(objnode == NULL);
> - kp->objnodes[kp->nr - 1] = NULL;
> - kp->nr--;
> - count = atomic_inc_return(&zcache_curr_objnode_count);
> - if (count > zcache_curr_objnode_count_max)
> - zcache_curr_objnode_count_max = count;
> -out:
> - return objnode;
> -}
> -
> -static void zcache_objnode_free(struct tmem_objnode *objnode,
> - struct tmem_pool *pool)
> -{
> - atomic_dec(&zcache_curr_objnode_count);
> - BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0);
> - kmem_cache_free(zcache_objnode_cache, objnode);
> -}
> -
> -static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
> -{
> - struct tmem_obj *obj = NULL;
> - unsigned long count;
> - struct zcache_preload *kp;
> -
> - kp = &__get_cpu_var(zcache_preloads);
> - obj = kp->obj;
> - BUG_ON(obj == NULL);
> - kp->obj = NULL;
> - count = atomic_inc_return(&zcache_curr_obj_count);
> - if (count > zcache_curr_obj_count_max)
> - zcache_curr_obj_count_max = count;
> - return obj;
> -}
> -
> -static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
> -{
> - atomic_dec(&zcache_curr_obj_count);
> - BUG_ON(atomic_read(&zcache_curr_obj_count) < 0);
> - kmem_cache_free(zcache_obj_cache, obj);
> -}
> -
> -static struct tmem_hostops zcache_hostops = {
> - .obj_alloc = zcache_obj_alloc,
> - .obj_free = zcache_obj_free,
> - .objnode_alloc = zcache_objnode_alloc,
> - .objnode_free = zcache_objnode_free,
> -};
> -
> -/*
> - * zcache implementations for PAM page descriptor ops
> - */
> -
> -static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0);
> -static unsigned long zcache_curr_eph_pampd_count_max;
> -static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0);
> -static unsigned long zcache_curr_pers_pampd_count_max;
> -
> -/* forward reference */
> -static int zcache_compress(struct page *from, void **out_va, size_t *out_len);
> -
> -static void *zcache_pampd_create(struct tmem_pool *pool, struct tmem_oid *oid,
> - uint32_t index, struct page *page)
> -{
> - void *pampd = NULL, *cdata;
> - size_t clen;
> - int ret;
> - bool ephemeral = is_ephemeral(pool);
> - unsigned long count;
> -
> - if (ephemeral) {
> - ret = zcache_compress(page, &cdata, &clen);
> - if (ret == 0)
> -
> - goto out;
> - if (clen == 0 || clen > zbud_max_buddy_size()) {
> - zcache_compress_poor++;
> - goto out;
> - }
> - pampd = (void *)zbud_create(pool->pool_id, oid, index,
> - page, cdata, clen);
> - if (pampd != NULL) {
> - count = atomic_inc_return(&zcache_curr_eph_pampd_count);
> - if (count > zcache_curr_eph_pampd_count_max)
> - zcache_curr_eph_pampd_count_max = count;
> - }
> - } else {
> - /*
> - * FIXME: This is all the "policy" there is for now.
> - * 3/4 totpages should allow ~37% of RAM to be filled with
> - * compressed frontswap pages
> - */
> - if (atomic_read(&zcache_curr_pers_pampd_count) >
> - 3 * totalram_pages / 4)
> - goto out;
> - ret = zcache_compress(page, &cdata, &clen);
> - if (ret == 0)
> - goto out;
> - if (clen > zv_max_page_size) {
> - zcache_compress_poor++;
> - goto out;
> - }
> - pampd = (void *)zv_create(zcache_client.xvpool, pool->pool_id,
> - oid, index, cdata, clen);
> - if (pampd == NULL)
> - goto out;
> - count = atomic_inc_return(&zcache_curr_pers_pampd_count);
> - if (count > zcache_curr_pers_pampd_count_max)
> - zcache_curr_pers_pampd_count_max = count;
> - }
> -out:
> - return pampd;
> -}
> -
> -/*
> - * fill the pageframe corresponding to the struct page with the data
> - * from the passed pampd
> - */
> -static int zcache_pampd_get_data(struct page *page, void *pampd,
> - struct tmem_pool *pool)
> -{
> - int ret = 0;
> -
> - if (is_ephemeral(pool))
> - ret = zbud_decompress(page, pampd);
> - else
> - zv_decompress(page, pampd);
> - return ret;
> -}
> -
> -/*
> - * free the pampd and remove it from any zcache lists
> - * pampd must no longer be pointed to from any tmem data structures!
> - */
> -static void zcache_pampd_free(void *pampd, struct tmem_pool *pool)
> -{
> - if (is_ephemeral(pool)) {
> - zbud_free_and_delist((struct zbud_hdr *)pampd);
> - atomic_dec(&zcache_curr_eph_pampd_count);
> - BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0);
> - } else {
> - zv_free(zcache_client.xvpool, (struct zv_hdr *)pampd);
> - atomic_dec(&zcache_curr_pers_pampd_count);
> - BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0);
> - }
> -}
> -
> -static struct tmem_pamops zcache_pamops = {
> - .create = zcache_pampd_create,
> - .get_data = zcache_pampd_get_data,
> - .free = zcache_pampd_free,
> -};
> -
> -/*
> - * zcache compression/decompression and related per-cpu stuff
> - */
> -
> -#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS
> -#define LZO_DSTMEM_PAGE_ORDER 1
> -static DEFINE_PER_CPU(unsigned char *, zcache_workmem);
> -static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
> -
> -static int zcache_compress(struct page *from, void **out_va, size_t *out_len)
> -{
> - int ret = 0;
> - unsigned char *dmem = __get_cpu_var(zcache_dstmem);
> - unsigned char *wmem = __get_cpu_var(zcache_workmem);
> - char *from_va;
> -
> - BUG_ON(!irqs_disabled());
> - if (unlikely(dmem == NULL || wmem == NULL))
> - goto out; /* no buffer, so can't compress */
> - from_va = kmap_atomic(from, KM_USER0);
> - mb();
> - ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem);
> - BUG_ON(ret != LZO_E_OK);
> - *out_va = dmem;
> - kunmap_atomic(from_va, KM_USER0);
> - ret = 1;
> -out:
> - return ret;
> -}
> -
> -
> -static int zcache_cpu_notifier(struct notifier_block *nb,
> - unsigned long action, void *pcpu)
> -{
> - int cpu = (long)pcpu;
> - struct zcache_preload *kp;
> -
> - switch (action) {
> - case CPU_UP_PREPARE:
> - per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
> - GFP_KERNEL | __GFP_REPEAT,
> - LZO_DSTMEM_PAGE_ORDER),
> - per_cpu(zcache_workmem, cpu) =
> - kzalloc(LZO1X_MEM_COMPRESS,
> - GFP_KERNEL | __GFP_REPEAT);
> - break;
> - case CPU_DEAD:
> - case CPU_UP_CANCELED:
> - free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
> - LZO_DSTMEM_PAGE_ORDER);
> - per_cpu(zcache_dstmem, cpu) = NULL;
> - kfree(per_cpu(zcache_workmem, cpu));
> - per_cpu(zcache_workmem, cpu) = NULL;
> - kp = &per_cpu(zcache_preloads, cpu);
> - while (kp->nr) {
> - kmem_cache_free(zcache_objnode_cache,
> - kp->objnodes[kp->nr - 1]);
> - kp->objnodes[kp->nr - 1] = NULL;
> - kp->nr--;
> - }
> - kmem_cache_free(zcache_obj_cache, kp->obj);
> - free_page((unsigned long)kp->page);
> - break;
> - default:
> - break;
> - }
> - return NOTIFY_OK;
> -}
> -
> -static struct notifier_block zcache_cpu_notifier_block = {
> - .notifier_call = zcache_cpu_notifier
> -};
> -
> -#ifdef CONFIG_SYSFS
> -#define ZCACHE_SYSFS_RO(_name) \
> - static ssize_t zcache_##_name##_show(struct kobject *kobj, \
> - struct kobj_attribute *attr, char *buf) \
> - { \
> - return sprintf(buf, "%lu\n", zcache_##_name); \
> - } \
> - static struct kobj_attribute zcache_##_name##_attr = { \
> - .attr = { .name = __stringify(_name), .mode = 0444 }, \
> - .show = zcache_##_name##_show, \
> - }
> -
> -#define ZCACHE_SYSFS_RO_ATOMIC(_name) \
> - static ssize_t zcache_##_name##_show(struct kobject *kobj, \
> - struct kobj_attribute *attr, char *buf) \
> - { \
> - return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \
> - } \
> - static struct kobj_attribute zcache_##_name##_attr = { \
> - .attr = { .name = __stringify(_name), .mode = 0444 }, \
> - .show = zcache_##_name##_show, \
> - }
> -
> -#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \
> - static ssize_t zcache_##_name##_show(struct kobject *kobj, \
> - struct kobj_attribute *attr, char *buf) \
> - { \
> - return _func(buf); \
> - } \
> - static struct kobj_attribute zcache_##_name##_attr = { \
> - .attr = { .name = __stringify(_name), .mode = 0444 }, \
> - .show = zcache_##_name##_show, \
> - }
> -
> -ZCACHE_SYSFS_RO(curr_obj_count_max);
> -ZCACHE_SYSFS_RO(curr_objnode_count_max);
> -ZCACHE_SYSFS_RO(flush_total);
> -ZCACHE_SYSFS_RO(flush_found);
> -ZCACHE_SYSFS_RO(flobj_total);
> -ZCACHE_SYSFS_RO(flobj_found);
> -ZCACHE_SYSFS_RO(failed_eph_puts);
> -ZCACHE_SYSFS_RO(failed_pers_puts);
> -ZCACHE_SYSFS_RO(zbud_curr_zbytes);
> -ZCACHE_SYSFS_RO(zbud_cumul_zpages);
> -ZCACHE_SYSFS_RO(zbud_cumul_zbytes);
> -ZCACHE_SYSFS_RO(zbud_buddied_count);
> -ZCACHE_SYSFS_RO(zbpg_unused_list_count);
> -ZCACHE_SYSFS_RO(evicted_raw_pages);
> -ZCACHE_SYSFS_RO(evicted_unbuddied_pages);
> -ZCACHE_SYSFS_RO(evicted_buddied_pages);
> -ZCACHE_SYSFS_RO(failed_get_free_pages);
> -ZCACHE_SYSFS_RO(failed_alloc);
> -ZCACHE_SYSFS_RO(put_to_flush);
> -ZCACHE_SYSFS_RO(aborted_preload);
> -ZCACHE_SYSFS_RO(aborted_shrink);
> -ZCACHE_SYSFS_RO(compress_poor);
> -ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages);
> -ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages);
> -ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count);
> -ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count);
> -ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts,
> - zbud_show_unbuddied_list_counts);
> -ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts,
> - zbud_show_cumul_chunk_counts);
> -
> -static struct attribute *zcache_attrs[] = {
> - &zcache_curr_obj_count_attr.attr,
> - &zcache_curr_obj_count_max_attr.attr,
> - &zcache_curr_objnode_count_attr.attr,
> - &zcache_curr_objnode_count_max_attr.attr,
> - &zcache_flush_total_attr.attr,
> - &zcache_flobj_total_attr.attr,
> - &zcache_flush_found_attr.attr,
> - &zcache_flobj_found_attr.attr,
> - &zcache_failed_eph_puts_attr.attr,
> - &zcache_failed_pers_puts_attr.attr,
> - &zcache_compress_poor_attr.attr,
> - &zcache_zbud_curr_raw_pages_attr.attr,
> - &zcache_zbud_curr_zpages_attr.attr,
> - &zcache_zbud_curr_zbytes_attr.attr,
> - &zcache_zbud_cumul_zpages_attr.attr,
> - &zcache_zbud_cumul_zbytes_attr.attr,
> - &zcache_zbud_buddied_count_attr.attr,
> - &zcache_zbpg_unused_list_count_attr.attr,
> - &zcache_evicted_raw_pages_attr.attr,
> - &zcache_evicted_unbuddied_pages_attr.attr,
> - &zcache_evicted_buddied_pages_attr.attr,
> - &zcache_failed_get_free_pages_attr.attr,
> - &zcache_failed_alloc_attr.attr,
> - &zcache_put_to_flush_attr.attr,
> - &zcache_aborted_preload_attr.attr,
> - &zcache_aborted_shrink_attr.attr,
> - &zcache_zbud_unbuddied_list_counts_attr.attr,
> - &zcache_zbud_cumul_chunk_counts_attr.attr,
> - NULL,
> -};
> -
> -static struct attribute_group zcache_attr_group = {
> - .attrs = zcache_attrs,
> - .name = "zcache",
> -};
> -
> -#endif /* CONFIG_SYSFS */
> -/*
> - * When zcache is disabled ("frozen"), pools can be created and destroyed,
> - * but all puts (and thus all other operations that require memory allocation)
> - * must fail. If zcache is unfrozen, accepts puts, then frozen again,
> - * data consistency requires all puts while frozen to be converted into
> - * flushes.
> - */
> -static bool zcache_freeze;
> -
> -/*
> - * zcache shrinker interface (only useful for ephemeral pages, so zbud only)
> - */
> -static int shrink_zcache_memory(struct shrinker *shrink,
> - struct shrink_control *sc)
> -{
> - int ret = -1;
> - int nr = sc->nr_to_scan;
> - gfp_t gfp_mask = sc->gfp_mask;
> -
> - if (nr >= 0) {
> - if (!(gfp_mask & __GFP_FS))
> - /* does this case really need to be skipped? */
> - goto out;
> - if (spin_trylock(&zcache_direct_reclaim_lock)) {
> - zbud_evict_pages(nr);
> - spin_unlock(&zcache_direct_reclaim_lock);
> - } else
> - zcache_aborted_shrink++;
> - }
> - ret = (int)atomic_read(&zcache_zbud_curr_raw_pages);
> -out:
> - return ret;
> -}
> -
> -static struct shrinker zcache_shrinker = {
> - .shrink = shrink_zcache_memory,
> - .seeks = DEFAULT_SEEKS,
> -};
> -
> -/*
> - * zcache shims between cleancache/frontswap ops and tmem
> - */
> -
> -static int zcache_put_page(int pool_id, struct tmem_oid *oidp,
> - uint32_t index, struct page *page)
> -{
> - struct tmem_pool *pool;
> - int ret = -1;
> -
> - BUG_ON(!irqs_disabled());
> - pool = zcache_get_pool_by_id(pool_id);
> - if (unlikely(pool == NULL))
> - goto out;
> - if (!zcache_freeze && zcache_do_preload(pool) == 0) {
> - /* preload does preempt_disable on success */
> - ret = tmem_put(pool, oidp, index, page);
> - if (ret < 0) {
> - if (is_ephemeral(pool))
> - zcache_failed_eph_puts++;
> - else
> - zcache_failed_pers_puts++;
> - }
> - zcache_put_pool(pool);
> - preempt_enable_no_resched();
> - } else {
> - zcache_put_to_flush++;
> - if (atomic_read(&pool->obj_count) > 0)
> - /* the put fails whether the flush succeeds or not */
> - (void)tmem_flush_page(pool, oidp, index);
> - zcache_put_pool(pool);
> - }
> -out:
> - return ret;
> -}
> -
> -static int zcache_get_page(int pool_id, struct tmem_oid *oidp,
> - uint32_t index, struct page *page)
> -{
> - struct tmem_pool *pool;
> - int ret = -1;
> - unsigned long flags;
> -
> - local_irq_save(flags);
> - pool = zcache_get_pool_by_id(pool_id);
> - if (likely(pool != NULL)) {
> - if (atomic_read(&pool->obj_count) > 0)
> - ret = tmem_get(pool, oidp, index, page);
> - zcache_put_pool(pool);
> - }
> - local_irq_restore(flags);
> - return ret;
> -}
> -
> -static int zcache_flush_page(int pool_id, struct tmem_oid *oidp, uint32_t index)
> -{
> - struct tmem_pool *pool;
> - int ret = -1;
> - unsigned long flags;
> -
> - local_irq_save(flags);
> - zcache_flush_total++;
> - pool = zcache_get_pool_by_id(pool_id);
> - if (likely(pool != NULL)) {
> - if (atomic_read(&pool->obj_count) > 0)
> - ret = tmem_flush_page(pool, oidp, index);
> - zcache_put_pool(pool);
> - }
> - if (ret >= 0)
> - zcache_flush_found++;
> - local_irq_restore(flags);
> - return ret;
> -}
> -
> -static int zcache_flush_object(int pool_id, struct tmem_oid *oidp)
> -{
> - struct tmem_pool *pool;
> - int ret = -1;
> - unsigned long flags;
> -
> - local_irq_save(flags);
> - zcache_flobj_total++;
> - pool = zcache_get_pool_by_id(pool_id);
> - if (likely(pool != NULL)) {
> - if (atomic_read(&pool->obj_count) > 0)
> - ret = tmem_flush_object(pool, oidp);
> - zcache_put_pool(pool);
> - }
> - if (ret >= 0)
> - zcache_flobj_found++;
> - local_irq_restore(flags);
> - return ret;
> -}
> -
> -static int zcache_destroy_pool(int pool_id)
> -{
> - struct tmem_pool *pool = NULL;
> - int ret = -1;
> -
> - if (pool_id < 0)
> - goto out;
> - pool = zcache_client.tmem_pools[pool_id];
> - if (pool == NULL)
> - goto out;
> - zcache_client.tmem_pools[pool_id] = NULL;
> - /* wait for pool activity on other cpus to quiesce */
> - while (atomic_read(&pool->refcount) != 0)
> - ;
> - local_bh_disable();
> - ret = tmem_destroy_pool(pool);
> - local_bh_enable();
> - kfree(pool);
> - pr_info("zcache: destroyed pool id=%d\n", pool_id);
> -out:
> - return ret;
> -}
> -
> -static int zcache_new_pool(uint32_t flags)
> -{
> - int poolid = -1;
> - struct tmem_pool *pool;
> -
> - pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL);
> - if (pool == NULL) {
> - pr_info("zcache: pool creation failed: out of memory\n");
> - goto out;
> - }
> -
> - for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++)
> - if (zcache_client.tmem_pools[poolid] == NULL)
> - break;
> - if (poolid >= MAX_POOLS_PER_CLIENT) {
> - pr_info("zcache: pool creation failed: max exceeded\n");
> - kfree(pool);
> - poolid = -1;
> - goto out;
> - }
> - atomic_set(&pool->refcount, 0);
> - pool->client = &zcache_client;
> - pool->pool_id = poolid;
> - tmem_new_pool(pool, flags);
> - zcache_client.tmem_pools[poolid] = pool;
> - pr_info("zcache: created %s tmem pool, id=%d\n",
> - flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
> - poolid);
> -out:
> - return poolid;
> -}
> -
> -/**********
> - * Two kernel functionalities currently can be layered on top of tmem.
> - * These are "cleancache" which is used as a second-chance cache for clean
> - * page cache pages; and "frontswap" which is used for swap pages
> - * to avoid writes to disk. A generic "shim" is provided here for each
> - * to translate in-kernel semantics to zcache semantics.
> - */
> -
> -#ifdef CONFIG_CLEANCACHE
> -static void zcache_cleancache_put_page(int pool_id,
> - struct cleancache_filekey key,
> - pgoff_t index, struct page *page)
> -{
> - u32 ind = (u32) index;
> - struct tmem_oid oid = *(struct tmem_oid *)&key;
> -
> - if (likely(ind == index))
> - (void)zcache_put_page(pool_id, &oid, index, page);
> -}
> -
> -static int zcache_cleancache_get_page(int pool_id,
> - struct cleancache_filekey key,
> - pgoff_t index, struct page *page)
> -{
> - u32 ind = (u32) index;
> - struct tmem_oid oid = *(struct tmem_oid *)&key;
> - int ret = -1;
> -
> - if (likely(ind == index))
> - ret = zcache_get_page(pool_id, &oid, index, page);
> - return ret;
> -}
> -
> -static void zcache_cleancache_flush_page(int pool_id,
> - struct cleancache_filekey key,
> - pgoff_t index)
> -{
> - u32 ind = (u32) index;
> - struct tmem_oid oid = *(struct tmem_oid *)&key;
> -
> - if (likely(ind == index))
> - (void)zcache_flush_page(pool_id, &oid, ind);
> -}
> -
> -static void zcache_cleancache_flush_inode(int pool_id,
> - struct cleancache_filekey key)
> -{
> - struct tmem_oid oid = *(struct tmem_oid *)&key;
> -
> - (void)zcache_flush_object(pool_id, &oid);
> -}
> -
> -static void zcache_cleancache_flush_fs(int pool_id)
> -{
> - if (pool_id >= 0)
> - (void)zcache_destroy_pool(pool_id);
> -}
> -
> -static int zcache_cleancache_init_fs(size_t pagesize)
> -{
> - BUG_ON(sizeof(struct cleancache_filekey) !=
> - sizeof(struct tmem_oid));
> - BUG_ON(pagesize != PAGE_SIZE);
> - return zcache_new_pool(0);
> -}
> -
> -static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
> -{
> - /* shared pools are unsupported and map to private */
> - BUG_ON(sizeof(struct cleancache_filekey) !=
> - sizeof(struct tmem_oid));
> - BUG_ON(pagesize != PAGE_SIZE);
> - return zcache_new_pool(0);
> -}
> -
> -static struct cleancache_ops zcache_cleancache_ops = {
> - .put_page = zcache_cleancache_put_page,
> - .get_page = zcache_cleancache_get_page,
> - .flush_page = zcache_cleancache_flush_page,
> - .flush_inode = zcache_cleancache_flush_inode,
> - .flush_fs = zcache_cleancache_flush_fs,
> - .init_shared_fs = zcache_cleancache_init_shared_fs,
> - .init_fs = zcache_cleancache_init_fs
> -};
> -
> -struct cleancache_ops zcache_cleancache_register_ops(void)
> -{
> - struct cleancache_ops old_ops =
> - cleancache_register_ops(&zcache_cleancache_ops);
> -
> - return old_ops;
> -}
> -#endif
> -
> -#ifdef CONFIG_FRONTSWAP
> -/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
> -static int zcache_frontswap_poolid = -1;
> -
> -/*
> - * Swizzling increases objects per swaptype, increasing tmem concurrency
> - * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
> - */
> -#define SWIZ_BITS 4
> -#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
> -#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
> -#define iswiz(_ind) (_ind >> SWIZ_BITS)
> -
> -static inline struct tmem_oid oswiz(unsigned type, u32 ind)
> -{
> - struct tmem_oid oid = { .oid = { 0 } };
> - oid.oid[0] = _oswiz(type, ind);
> - return oid;
> -}
> -
> -static int zcache_frontswap_put_page(unsigned type, pgoff_t offset,
> - struct page *page)
> -{
> - u64 ind64 = (u64)offset;
> - u32 ind = (u32)offset;
> - struct tmem_oid oid = oswiz(type, ind);
> - int ret = -1;
> - unsigned long flags;
> -
> - BUG_ON(!PageLocked(page));
> - if (likely(ind64 == ind)) {
> - local_irq_save(flags);
> - ret = zcache_put_page(zcache_frontswap_poolid, &oid,
> - iswiz(ind), page);
> - local_irq_restore(flags);
> - }
> - return ret;
> -}
> -
> -/* returns 0 if the page was successfully gotten from frontswap, -1 if
> - * was not present (should never happen!) */
> -static int zcache_frontswap_get_page(unsigned type, pgoff_t offset,
> - struct page *page)
> -{
> - u64 ind64 = (u64)offset;
> - u32 ind = (u32)offset;
> - struct tmem_oid oid = oswiz(type, ind);
> - int ret = -1;
> -
> - BUG_ON(!PageLocked(page));
> - if (likely(ind64 == ind))
> - ret = zcache_get_page(zcache_frontswap_poolid, &oid,
> - iswiz(ind), page);
> - return ret;
> -}
> -
> -/* flush a single page from frontswap */
> -static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
> -{
> - u64 ind64 = (u64)offset;
> - u32 ind = (u32)offset;
> - struct tmem_oid oid = oswiz(type, ind);
> -
> - if (likely(ind64 == ind))
> - (void)zcache_flush_page(zcache_frontswap_poolid, &oid,
> - iswiz(ind));
> -}
> -
> -/* flush all pages from the passed swaptype */
> -static void zcache_frontswap_flush_area(unsigned type)
> -{
> - struct tmem_oid oid;
> - int ind;
> -
> - for (ind = SWIZ_MASK; ind >= 0; ind--) {
> - oid = oswiz(type, ind);
> - (void)zcache_flush_object(zcache_frontswap_poolid, &oid);
> - }
> -}
> -
> -static void zcache_frontswap_init(unsigned ignored)
> -{
> - /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
> - if (zcache_frontswap_poolid < 0)
> - zcache_frontswap_poolid = zcache_new_pool(TMEM_POOL_PERSIST);
> -}
> -
> -static struct frontswap_ops zcache_frontswap_ops = {
> - .put_page = zcache_frontswap_put_page,
> - .get_page = zcache_frontswap_get_page,
> - .flush_page = zcache_frontswap_flush_page,
> - .flush_area = zcache_frontswap_flush_area,
> - .init = zcache_frontswap_init
> -};
> -
> -struct frontswap_ops zcache_frontswap_register_ops(void)
> -{
> - struct frontswap_ops old_ops =
> - frontswap_register_ops(&zcache_frontswap_ops);
> -
> - return old_ops;
> -}
> -#endif
> -
> -/*
> - * zcache initialization
> - * NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR
> - * NOTHING HAPPENS!
> - */
> -
> -static int zcache_enabled;
> -
> -static int __init enable_zcache(char *s)
> -{
> - zcache_enabled = 1;
> - return 1;
> -}
> -__setup("zcache", enable_zcache);
> -
> -/* allow independent dynamic disabling of cleancache and frontswap */
> -
> -static int use_cleancache = 1;
> -
> -static int __init no_cleancache(char *s)
> -{
> - use_cleancache = 0;
> - return 1;
> -}
> -
> -__setup("nocleancache", no_cleancache);
> -
> -static int use_frontswap = 1;
> -
> -static int __init no_frontswap(char *s)
> -{
> - use_frontswap = 0;
> - return 1;
> -}
> -
> -__setup("nofrontswap", no_frontswap);
> -
> -static int __init zcache_init(void)
> -{
> -#ifdef CONFIG_SYSFS
> - int ret = 0;
> -
> - ret = sysfs_create_group(mm_kobj, &zcache_attr_group);
> - if (ret) {
> - pr_err("zcache: can't create sysfs\n");
> - goto out;
> - }
> -#endif /* CONFIG_SYSFS */
> -#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP)
> - if (zcache_enabled) {
> - unsigned int cpu;
> -
> - tmem_register_hostops(&zcache_hostops);
> - tmem_register_pamops(&zcache_pamops);
> - ret = register_cpu_notifier(&zcache_cpu_notifier_block);
> - if (ret) {
> - pr_err("zcache: can't register cpu notifier\n");
> - goto out;
> - }
> - for_each_online_cpu(cpu) {
> - void *pcpu = (void *)(long)cpu;
> - zcache_cpu_notifier(&zcache_cpu_notifier_block,
> - CPU_UP_PREPARE, pcpu);
> - }
> - }
> - zcache_objnode_cache = kmem_cache_create("zcache_objnode",
> - sizeof(struct tmem_objnode), 0, 0, NULL);
> - zcache_obj_cache = kmem_cache_create("zcache_obj",
> - sizeof(struct tmem_obj), 0, 0, NULL);
> -#endif
> -#ifdef CONFIG_CLEANCACHE
> - if (zcache_enabled && use_cleancache) {
> - struct cleancache_ops old_ops;
> -
> - zbud_init();
> - register_shrinker(&zcache_shrinker);
> - old_ops = zcache_cleancache_register_ops();
> - pr_info("zcache: cleancache enabled using kernel "
> - "transcendent memory and compression buddies\n");
> - if (old_ops.init_fs != NULL)
> - pr_warning("zcache: cleancache_ops overridden");
> - }
> -#endif
> -#ifdef CONFIG_FRONTSWAP
> - if (zcache_enabled && use_frontswap) {
> - struct frontswap_ops old_ops;
> -
> - zcache_client.xvpool = xv_create_pool();
> - if (zcache_client.xvpool == NULL) {
> - pr_err("zcache: can't create xvpool\n");
> - goto out;
> - }
> - old_ops = zcache_frontswap_register_ops();
> - pr_info("zcache: frontswap enabled using kernel "
> - "transcendent memory and xvmalloc\n");
> - if (old_ops.init != NULL)
> - pr_warning("ktmem: frontswap_ops overridden");
> - }
> -#endif
> -out:
> - return ret;
> -}
> -
> -module_init(zcache_init)
> diff --git a/drivers/staging/zcache/zcache_drv.c b/drivers/staging/zcache/zcache_drv.c
> new file mode 100644
> index 0000000..77ac2d4
> --- /dev/null
> +++ b/drivers/staging/zcache/zcache_drv.c
> @@ -0,0 +1,1661 @@
> +/*
> + * zcache.c
> + *
> + * Copyright (c) 2010,2011, Dan Magenheimer, Oracle Corp.
> + * Copyright (c) 2010,2011, Nitin Gupta
> + *
> + * Zcache provides an in-kernel "host implementation" for transcendent memory
> + * and, thus indirectly, for cleancache and frontswap. Zcache includes two
> + * page-accessible memory [1] interfaces, both utilizing lzo1x compression:
> + * 1) "compression buddies" ("zbud") is used for ephemeral pages
> + * 2) xvmalloc is used for persistent pages.
> + * Xvmalloc (based on the TLSF allocator) has very low fragmentation
> + * so maximizes space efficiency, while zbud allows pairs (and potentially,
> + * in the future, more than a pair of) compressed pages to be closely linked
> + * so that reclaiming can be done via the kernel's physical-page-oriented
> + * "shrinker" interface.
> + *
> + * [1] For a definition of page-accessible memory (aka PAM), see:
> + * http://marc.info/?l=linux-mm&m=127811271605009
> + */
> +
> +#include <linux/cpu.h>
> +#include <linux/highmem.h>
> +#include <linux/list.h>
> +#include <linux/lzo.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +#include <linux/types.h>
> +#include <linux/atomic.h>
> +#include "tmem.h"
> +
> +#include "../zram/xvmalloc.h" /* if built in drivers/staging */
> +
> +#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP))
> +#error "zcache is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP"
> +#endif
> +#ifdef CONFIG_CLEANCACHE
> +#include <linux/cleancache.h>
> +#endif
> +#ifdef CONFIG_FRONTSWAP
> +#include <linux/frontswap.h>
> +#endif
> +
> +#if 0
> +/* this is more aggressive but may cause other problems? */
> +#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN)
> +#else
> +#define ZCACHE_GFP_MASK \
> + (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
> +#endif
> +
> +/**********
> + * Compression buddies ("zbud") provides for packing two (or, possibly
> + * in the future, more) compressed ephemeral pages into a single "raw"
> + * (physical) page and tracking them with data structures so that
> + * the raw pages can be easily reclaimed.
> + *
> + * A zbud page ("zbpg") is an aligned page containing a list_head,
> + * a lock, and two "zbud headers". The remainder of the physical
> + * page is divided up into aligned 64-byte "chunks" which contain
> + * the compressed data for zero, one, or two zbuds. Each zbpg
> + * resides on: (1) an "unused list" if it has no zbuds; (2) a
> + * "buddied" list if it is fully populated with two zbuds; or
> + * (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks
> + * the one unbuddied zbud uses. The data inside a zbpg cannot be
> + * read or written unless the zbpg's lock is held.
> + */
> +
> +#define ZBH_SENTINEL 0x43214321
> +#define ZBPG_SENTINEL 0xdeadbeef
> +
> +#define ZBUD_MAX_BUDS 2
> +
> +struct zbud_hdr {
> + uint32_t pool_id;
> + struct tmem_oid oid;
> + uint32_t index;
> + uint16_t size; /* compressed size in bytes, zero means unused */
> + DECL_SENTINEL
> +};
> +
> +struct zbud_page {
> + struct list_head bud_list;
> + spinlock_t lock;
> + struct zbud_hdr buddy[ZBUD_MAX_BUDS];
> + DECL_SENTINEL
> + /* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */
> +};
> +
> +#define CHUNK_SHIFT 6
> +#define CHUNK_SIZE (1 << CHUNK_SHIFT)
> +#define CHUNK_MASK (~(CHUNK_SIZE-1))
> +#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \
> + CHUNK_MASK) >> CHUNK_SHIFT)
> +#define MAX_CHUNK (NCHUNKS-1)
> +
> +static struct {
> + struct list_head list;
> + unsigned count;
> +} zbud_unbuddied[NCHUNKS];
> +/* list N contains pages with N chunks USED and NCHUNKS-N unused */
> +/* element 0 is never used but optimizing that isn't worth it */
> +static unsigned long zbud_cumul_chunk_counts[NCHUNKS];
> +
> +struct list_head zbud_buddied_list;
> +static unsigned long zcache_zbud_buddied_count;
> +
> +/* protects the buddied list and all unbuddied lists */
> +static DEFINE_SPINLOCK(zbud_budlists_spinlock);
> +
> +static LIST_HEAD(zbpg_unused_list);
> +static unsigned long zcache_zbpg_unused_list_count;
> +
> +/* protects the unused page list */
> +static DEFINE_SPINLOCK(zbpg_unused_list_spinlock);
> +
> +static atomic_t zcache_zbud_curr_raw_pages;
> +static atomic_t zcache_zbud_curr_zpages;
> +static unsigned long zcache_zbud_curr_zbytes;
> +static unsigned long zcache_zbud_cumul_zpages;
> +static unsigned long zcache_zbud_cumul_zbytes;
> +static unsigned long zcache_compress_poor;
> +
> +/* forward references */
> +static void *zcache_get_free_page(void);
> +static void zcache_free_page(void *p);
> +
> +/*
> + * zbud helper functions
> + */
> +
> +static inline unsigned zbud_max_buddy_size(void)
> +{
> + return MAX_CHUNK << CHUNK_SHIFT;
> +}
> +
> +static inline unsigned zbud_size_to_chunks(unsigned size)
> +{
> + BUG_ON(size == 0 || size > zbud_max_buddy_size());
> + return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
> +}
> +
> +static inline int zbud_budnum(struct zbud_hdr *zh)
> +{
> + unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1);
> + struct zbud_page *zbpg = NULL;
> + unsigned budnum = -1U;
> + int i;
> +
> + for (i = 0; i < ZBUD_MAX_BUDS; i++)
> + if (offset == offsetof(typeof(*zbpg), buddy[i])) {
> + budnum = i;
> + break;
> + }
> + BUG_ON(budnum == -1U);
> + return budnum;
> +}
> +
> +static char *zbud_data(struct zbud_hdr *zh, unsigned size)
> +{
> + struct zbud_page *zbpg;
> + char *p;
> + unsigned budnum;
> +
> + ASSERT_SENTINEL(zh, ZBH);
> + budnum = zbud_budnum(zh);
> + BUG_ON(size == 0 || size > zbud_max_buddy_size());
> + zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
> + ASSERT_SPINLOCK(&zbpg->lock);
> + p = (char *)zbpg;
> + if (budnum == 0)
> + p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
> + CHUNK_MASK);
> + else if (budnum == 1)
> + p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
> + return p;
> +}
> +
> +/*
> + * zbud raw page management
> + */
> +
> +static struct zbud_page *zbud_alloc_raw_page(void)
> +{
> + struct zbud_page *zbpg = NULL;
> + struct zbud_hdr *zh0, *zh1;
> + bool recycled = 0;
> +
> + /* if any pages on the zbpg list, use one */
> + spin_lock(&zbpg_unused_list_spinlock);
> + if (!list_empty(&zbpg_unused_list)) {
> + zbpg = list_first_entry(&zbpg_unused_list,
> + struct zbud_page, bud_list);
> + list_del_init(&zbpg->bud_list);
> + zcache_zbpg_unused_list_count--;
> + recycled = 1;
> + }
> + spin_unlock(&zbpg_unused_list_spinlock);
> + if (zbpg == NULL)
> + /* none on zbpg list, try to get a kernel page */
> + zbpg = zcache_get_free_page();
> + if (likely(zbpg != NULL)) {
> + INIT_LIST_HEAD(&zbpg->bud_list);
> + zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
> + spin_lock_init(&zbpg->lock);
> + if (recycled) {
> + ASSERT_INVERTED_SENTINEL(zbpg, ZBPG);
> + SET_SENTINEL(zbpg, ZBPG);
> + BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
> + BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
> + } else {
> + atomic_inc(&zcache_zbud_curr_raw_pages);
> + INIT_LIST_HEAD(&zbpg->bud_list);
> + SET_SENTINEL(zbpg, ZBPG);
> + zh0->size = 0; zh1->size = 0;
> + tmem_oid_set_invalid(&zh0->oid);
> + tmem_oid_set_invalid(&zh1->oid);
> + }
> + }
> + return zbpg;
> +}
> +
> +static void zbud_free_raw_page(struct zbud_page *zbpg)
> +{
> + struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1];
> +
> + ASSERT_SENTINEL(zbpg, ZBPG);
> + BUG_ON(!list_empty(&zbpg->bud_list));
> + ASSERT_SPINLOCK(&zbpg->lock);
> + BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
> + BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
> + INVERT_SENTINEL(zbpg, ZBPG);
> + spin_unlock(&zbpg->lock);
> + spin_lock(&zbpg_unused_list_spinlock);
> + list_add(&zbpg->bud_list, &zbpg_unused_list);
> + zcache_zbpg_unused_list_count++;
> + spin_unlock(&zbpg_unused_list_spinlock);
> +}
> +
> +/*
> + * core zbud handling routines
> + */
> +
> +static unsigned zbud_free(struct zbud_hdr *zh)
> +{
> + unsigned size;
> +
> + ASSERT_SENTINEL(zh, ZBH);
> + BUG_ON(!tmem_oid_valid(&zh->oid));
> + size = zh->size;
> + BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
> + zh->size = 0;
> + tmem_oid_set_invalid(&zh->oid);
> + INVERT_SENTINEL(zh, ZBH);
> + zcache_zbud_curr_zbytes -= size;
> + atomic_dec(&zcache_zbud_curr_zpages);
> + return size;
> +}
> +
> +static void zbud_free_and_delist(struct zbud_hdr *zh)
> +{
> + unsigned chunks;
> + struct zbud_hdr *zh_other;
> + unsigned budnum = zbud_budnum(zh), size;
> + struct zbud_page *zbpg =
> + container_of(zh, struct zbud_page, buddy[budnum]);
> +
> + spin_lock(&zbpg->lock);
> + if (list_empty(&zbpg->bud_list)) {
> + /* ignore zombie page... see zbud_evict_pages() */
> + spin_unlock(&zbpg->lock);
> + return;
> + }
> + size = zbud_free(zh);
> + ASSERT_SPINLOCK(&zbpg->lock);
> + zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0];
> + if (zh_other->size == 0) { /* was unbuddied: unlist and free */
> + chunks = zbud_size_to_chunks(size) ;
> + spin_lock(&zbud_budlists_spinlock);
> + BUG_ON(list_empty(&zbud_unbuddied[chunks].list));
> + list_del_init(&zbpg->bud_list);
> + zbud_unbuddied[chunks].count--;
> + spin_unlock(&zbud_budlists_spinlock);
> + zbud_free_raw_page(zbpg);
> + } else { /* was buddied: move remaining buddy to unbuddied list */
> + chunks = zbud_size_to_chunks(zh_other->size) ;
> + spin_lock(&zbud_budlists_spinlock);
> + list_del_init(&zbpg->bud_list);
> + zcache_zbud_buddied_count--;
> + list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list);
> + zbud_unbuddied[chunks].count++;
> + spin_unlock(&zbud_budlists_spinlock);
> + spin_unlock(&zbpg->lock);
> + }
> +}
> +
> +static struct zbud_hdr *zbud_create(uint32_t pool_id, struct tmem_oid *oid,
> + uint32_t index, struct page *page,
> + void *cdata, unsigned size)
> +{
> + struct zbud_hdr *zh0, *zh1, *zh = NULL;
> + struct zbud_page *zbpg = NULL, *ztmp;
> + unsigned nchunks;
> + char *to;
> + int i, found_good_buddy = 0;
> +
> + nchunks = zbud_size_to_chunks(size) ;
> + for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) {
> + spin_lock(&zbud_budlists_spinlock);
> + if (!list_empty(&zbud_unbuddied[i].list)) {
> + list_for_each_entry_safe(zbpg, ztmp,
> + &zbud_unbuddied[i].list, bud_list) {
> + if (spin_trylock(&zbpg->lock)) {
> + found_good_buddy = i;
> + goto found_unbuddied;
> + }
> + }
> + }
> + spin_unlock(&zbud_budlists_spinlock);
> + }
> + /* didn't find a good buddy, try allocating a new page */
> + zbpg = zbud_alloc_raw_page();
> + if (unlikely(zbpg == NULL))
> + goto out;
> + /* ok, have a page, now compress the data before taking locks */
> + spin_lock(&zbpg->lock);
> + spin_lock(&zbud_budlists_spinlock);
> + list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list);
> + zbud_unbuddied[nchunks].count++;
> + zh = &zbpg->buddy[0];
> + goto init_zh;
> +
> +found_unbuddied:
> + ASSERT_SPINLOCK(&zbpg->lock);
> + zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
> + BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0)));
> + if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */
> + ASSERT_SENTINEL(zh0, ZBH);
> + zh = zh1;
> + } else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */
> + ASSERT_SENTINEL(zh1, ZBH);
> + zh = zh0;
> + } else
> + BUG();
> + list_del_init(&zbpg->bud_list);
> + zbud_unbuddied[found_good_buddy].count--;
> + list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
> + zcache_zbud_buddied_count++;
> +
> +init_zh:
> + SET_SENTINEL(zh, ZBH);
> + zh->size = size;
> + zh->index = index;
> + zh->oid = *oid;
> + zh->pool_id = pool_id;
> + /* can wait to copy the data until the list locks are dropped */
> + spin_unlock(&zbud_budlists_spinlock);
> +
> + to = zbud_data(zh, size);
> + memcpy(to, cdata, size);
> + spin_unlock(&zbpg->lock);
> + zbud_cumul_chunk_counts[nchunks]++;
> + atomic_inc(&zcache_zbud_curr_zpages);
> + zcache_zbud_cumul_zpages++;
> + zcache_zbud_curr_zbytes += size;
> + zcache_zbud_cumul_zbytes += size;
> +out:
> + return zh;
> +}
> +
> +static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
> +{
> + struct zbud_page *zbpg;
> + unsigned budnum = zbud_budnum(zh);
> + size_t out_len = PAGE_SIZE;
> + char *to_va, *from_va;
> + unsigned size;
> + int ret = 0;
> +
> + zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
> + spin_lock(&zbpg->lock);
> + if (list_empty(&zbpg->bud_list)) {
> + /* ignore zombie page... see zbud_evict_pages() */
> + ret = -EINVAL;
> + goto out;
> + }
> + ASSERT_SENTINEL(zh, ZBH);
> + BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
> + to_va = kmap_atomic(page, KM_USER0);
> + size = zh->size;
> + from_va = zbud_data(zh, size);
> + ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len);
> + BUG_ON(ret != LZO_E_OK);
> + BUG_ON(out_len != PAGE_SIZE);
> + kunmap_atomic(to_va, KM_USER0);
> +out:
> + spin_unlock(&zbpg->lock);
> + return ret;
> +}
> +
> +/*
> + * The following routines handle shrinking of ephemeral pages by evicting
> + * pages "least valuable" first.
> + */
> +
> +static unsigned long zcache_evicted_raw_pages;
> +static unsigned long zcache_evicted_buddied_pages;
> +static unsigned long zcache_evicted_unbuddied_pages;
> +
> +static struct tmem_pool *zcache_get_pool_by_id(uint32_t poolid);
> +static void zcache_put_pool(struct tmem_pool *pool);
> +
> +/*
> + * Flush and free all zbuds in a zbpg, then free the pageframe
> + */
> +static void zbud_evict_zbpg(struct zbud_page *zbpg)
> +{
> + struct zbud_hdr *zh;
> + int i, j;
> + uint32_t pool_id[ZBUD_MAX_BUDS], index[ZBUD_MAX_BUDS];
> + struct tmem_oid oid[ZBUD_MAX_BUDS];
> + struct tmem_pool *pool;
> +
> + ASSERT_SPINLOCK(&zbpg->lock);
> + BUG_ON(!list_empty(&zbpg->bud_list));
> + for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) {
> + zh = &zbpg->buddy[i];
> + if (zh->size) {
> + pool_id[j] = zh->pool_id;
> + oid[j] = zh->oid;
> + index[j] = zh->index;
> + j++;
> + zbud_free(zh);
> + }
> + }
> + spin_unlock(&zbpg->lock);
> + for (i = 0; i < j; i++) {
> + pool = zcache_get_pool_by_id(pool_id[i]);
> + if (pool != NULL) {
> + tmem_flush_page(pool, &oid[i], index[i]);
> + zcache_put_pool(pool);
> + }
> + }
> + ASSERT_SENTINEL(zbpg, ZBPG);
> + spin_lock(&zbpg->lock);
> + zbud_free_raw_page(zbpg);
> +}
> +
> +/*
> + * Free nr pages. This code is funky because we want to hold the locks
> + * protecting various lists for as short a time as possible, and in some
> + * circumstances the list may change asynchronously when the list lock is
> + * not held. In some cases we also trylock not only to avoid waiting on a
> + * page in use by another cpu, but also to avoid potential deadlock due to
> + * lock inversion.
> + */
> +static void zbud_evict_pages(int nr)
> +{
> + struct zbud_page *zbpg;
> + int i;
> +
> + /* first try freeing any pages on unused list */
> +retry_unused_list:
> + spin_lock_bh(&zbpg_unused_list_spinlock);
> + if (!list_empty(&zbpg_unused_list)) {
> + /* can't walk list here, since it may change when unlocked */
> + zbpg = list_first_entry(&zbpg_unused_list,
> + struct zbud_page, bud_list);
> + list_del_init(&zbpg->bud_list);
> + zcache_zbpg_unused_list_count--;
> + atomic_dec(&zcache_zbud_curr_raw_pages);
> + spin_unlock_bh(&zbpg_unused_list_spinlock);
> + zcache_free_page(zbpg);
> + zcache_evicted_raw_pages++;
> + if (--nr <= 0)
> + goto out;
> + goto retry_unused_list;
> + }
> + spin_unlock_bh(&zbpg_unused_list_spinlock);
> +
> + /* now try freeing unbuddied pages, starting with least space avail */
> + for (i = 0; i < MAX_CHUNK; i++) {
> +retry_unbud_list_i:
> + spin_lock_bh(&zbud_budlists_spinlock);
> + if (list_empty(&zbud_unbuddied[i].list)) {
> + spin_unlock_bh(&zbud_budlists_spinlock);
> + continue;
> + }
> + list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
> + if (unlikely(!spin_trylock(&zbpg->lock)))
> + continue;
> + list_del_init(&zbpg->bud_list);
> + zbud_unbuddied[i].count--;
> + spin_unlock(&zbud_budlists_spinlock);
> + zcache_evicted_unbuddied_pages++;
> + /* want budlists unlocked when doing zbpg eviction */
> + zbud_evict_zbpg(zbpg);
> + local_bh_enable();
> + if (--nr <= 0)
> + goto out;
> + goto retry_unbud_list_i;
> + }
> + spin_unlock_bh(&zbud_budlists_spinlock);
> + }
> +
> + /* as a last resort, free buddied pages */
> +retry_bud_list:
> + spin_lock_bh(&zbud_budlists_spinlock);
> + if (list_empty(&zbud_buddied_list)) {
> + spin_unlock_bh(&zbud_budlists_spinlock);
> + goto out;
> + }
> + list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
> + if (unlikely(!spin_trylock(&zbpg->lock)))
> + continue;
> + list_del_init(&zbpg->bud_list);
> + zcache_zbud_buddied_count--;
> + spin_unlock(&zbud_budlists_spinlock);
> + zcache_evicted_buddied_pages++;
> + /* want budlists unlocked when doing zbpg eviction */
> + zbud_evict_zbpg(zbpg);
> + local_bh_enable();
> + if (--nr <= 0)
> + goto out;
> + goto retry_bud_list;
> + }
> + spin_unlock_bh(&zbud_budlists_spinlock);
> +out:
> + return;
> +}
> +
> +static void zbud_init(void)
> +{
> + int i;
> +
> + INIT_LIST_HEAD(&zbud_buddied_list);
> + zcache_zbud_buddied_count = 0;
> + for (i = 0; i < NCHUNKS; i++) {
> + INIT_LIST_HEAD(&zbud_unbuddied[i].list);
> + zbud_unbuddied[i].count = 0;
> + }
> +}
> +
> +#ifdef CONFIG_SYSFS
> +/*
> + * These sysfs routines show a nice distribution of how many zbpg's are
> + * currently (and have ever been placed) in each unbuddied list. It's fun
> + * to watch but can probably go away before final merge.
> + */
> +static int zbud_show_unbuddied_list_counts(char *buf)
> +{
> + int i;
> + char *p = buf;
> +
> + for (i = 0; i < NCHUNKS - 1; i++)
> + p += sprintf(p, "%u ", zbud_unbuddied[i].count);
> + p += sprintf(p, "%d\n", zbud_unbuddied[i].count);
> + return p - buf;
> +}
> +
> +static int zbud_show_cumul_chunk_counts(char *buf)
> +{
> + unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0;
> + unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0;
> + unsigned long total_chunks_lte_42 = 0;
> + char *p = buf;
> +
> + for (i = 0; i < NCHUNKS; i++) {
> + p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]);
> + chunks += zbud_cumul_chunk_counts[i];
> + total_chunks += zbud_cumul_chunk_counts[i];
> + sum_total_chunks += i * zbud_cumul_chunk_counts[i];
> + if (i == 21)
> + total_chunks_lte_21 = total_chunks;
> + if (i == 32)
> + total_chunks_lte_32 = total_chunks;
> + if (i == 42)
> + total_chunks_lte_42 = total_chunks;
> + }
> + p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n",
> + total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42,
> + chunks == 0 ? 0 : sum_total_chunks / chunks);
> + return p - buf;
> +}
> +#endif
> +
> +/**********
> + * This "zv" PAM implementation combines the TLSF-based xvMalloc
> + * with lzo1x compression to maximize the amount of data that can
> + * be packed into a physical page.
> + *
> + * Zv represents a PAM page with the index and object (plus a "size" value
> + * necessary for decompression) immediately preceding the compressed data.
> + */
> +
> +#define ZVH_SENTINEL 0x43214321
> +
> +struct zv_hdr {
> + uint32_t pool_id;
> + struct tmem_oid oid;
> + uint32_t index;
> + DECL_SENTINEL
> +};
> +
> +static const int zv_max_page_size = (PAGE_SIZE / 8) * 7;
> +
> +static struct zv_hdr *zv_create(struct xv_pool *xvpool, uint32_t pool_id,
> + struct tmem_oid *oid, uint32_t index,
> + void *cdata, unsigned clen)
> +{
> + struct page *page;
> + struct zv_hdr *zv = NULL;
> + uint32_t offset;
> + int ret;
> +
> + BUG_ON(!irqs_disabled());
> + ret = xv_malloc(xvpool, clen + sizeof(struct zv_hdr),
> + &page, &offset, ZCACHE_GFP_MASK);
> + if (unlikely(ret))
> + goto out;
> + zv = kmap_atomic(page, KM_USER0) + offset;
> + zv->index = index;
> + zv->oid = *oid;
> + zv->pool_id = pool_id;
> + SET_SENTINEL(zv, ZVH);
> + memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen);
> + kunmap_atomic(zv, KM_USER0);
> +out:
> + return zv;
> +}
> +
> +static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv)
> +{
> + unsigned long flags;
> + struct page *page;
> + uint32_t offset;
> + uint16_t size;
> +
> + ASSERT_SENTINEL(zv, ZVH);
> + size = xv_get_object_size(zv) - sizeof(*zv);
> + BUG_ON(size == 0 || size > zv_max_page_size);
> + INVERT_SENTINEL(zv, ZVH);
> + page = virt_to_page(zv);
> + offset = (unsigned long)zv & ~PAGE_MASK;
> + local_irq_save(flags);
> + xv_free(xvpool, page, offset);
> + local_irq_restore(flags);
> +}
> +
> +static void zv_decompress(struct page *page, struct zv_hdr *zv)
> +{
> + size_t clen = PAGE_SIZE;
> + char *to_va;
> + unsigned size;
> + int ret;
> +
> + ASSERT_SENTINEL(zv, ZVH);
> + size = xv_get_object_size(zv) - sizeof(*zv);
> + BUG_ON(size == 0 || size > zv_max_page_size);
> + to_va = kmap_atomic(page, KM_USER0);
> + ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv),
> + size, to_va, &clen);
> + kunmap_atomic(to_va, KM_USER0);
> + BUG_ON(ret != LZO_E_OK);
> + BUG_ON(clen != PAGE_SIZE);
> +}
> +
> +/*
> + * zcache core code starts here
> + */
> +
> +/* useful stats not collected by cleancache or frontswap */
> +static unsigned long zcache_flush_total;
> +static unsigned long zcache_flush_found;
> +static unsigned long zcache_flobj_total;
> +static unsigned long zcache_flobj_found;
> +static unsigned long zcache_failed_eph_puts;
> +static unsigned long zcache_failed_pers_puts;
> +
> +#define MAX_POOLS_PER_CLIENT 16
> +
> +static struct {
> + struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT];
> + struct xv_pool *xvpool;
> +} zcache_client;
> +
> +/*
> + * Tmem operations assume the poolid implies the invoking client.
> + * Zcache only has one client (the kernel itself), so translate
> + * the poolid into the tmem_pool allocated for it. A KVM version
> + * of zcache would have one client per guest and each client might
> + * have a poolid==N.
> + */
> +static struct tmem_pool *zcache_get_pool_by_id(uint32_t poolid)
> +{
> + struct tmem_pool *pool = NULL;
> +
> + if (poolid >= 0) {
> + pool = zcache_client.tmem_pools[poolid];
> + if (pool != NULL)
> + atomic_inc(&pool->refcount);
> + }
> + return pool;
> +}
> +
> +static void zcache_put_pool(struct tmem_pool *pool)
> +{
> + if (pool != NULL)
> + atomic_dec(&pool->refcount);
> +}
> +
> +/* counters for debugging */
> +static unsigned long zcache_failed_get_free_pages;
> +static unsigned long zcache_failed_alloc;
> +static unsigned long zcache_put_to_flush;
> +static unsigned long zcache_aborted_preload;
> +static unsigned long zcache_aborted_shrink;
> +
> +/*
> + * Ensure that memory allocation requests in zcache don't result
> + * in direct reclaim requests via the shrinker, which would cause
> + * an infinite loop. Maybe a GFP flag would be better?
> + */
> +static DEFINE_SPINLOCK(zcache_direct_reclaim_lock);
> +
> +/*
> + * for now, used named slabs so can easily track usage; later can
> + * either just use kmalloc, or perhaps add a slab-like allocator
> + * to more carefully manage total memory utilization
> + */
> +static struct kmem_cache *zcache_objnode_cache;
> +static struct kmem_cache *zcache_obj_cache;
> +static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0);
> +static unsigned long zcache_curr_obj_count_max;
> +static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0);
> +static unsigned long zcache_curr_objnode_count_max;
> +
> +/*
> + * to avoid memory allocation recursion (e.g. due to direct reclaim), we
> + * preload all necessary data structures so the hostops callbacks never
> + * actually do a malloc
> + */
> +struct zcache_preload {
> + void *page;
> + struct tmem_obj *obj;
> + int nr;
> + struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH];
> +};
> +static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
> +
> +static int zcache_do_preload(struct tmem_pool *pool)
> +{
> + struct zcache_preload *kp;
> + struct tmem_objnode *objnode;
> + struct tmem_obj *obj;
> + void *page;
> + int ret = -ENOMEM;
> +
> + if (unlikely(zcache_objnode_cache == NULL))
> + goto out;
> + if (unlikely(zcache_obj_cache == NULL))
> + goto out;
> + if (!spin_trylock(&zcache_direct_reclaim_lock)) {
> + zcache_aborted_preload++;
> + goto out;
> + }
> + preempt_disable();
> + kp = &__get_cpu_var(zcache_preloads);
> + while (kp->nr < ARRAY_SIZE(kp->objnodes)) {
> + preempt_enable_no_resched();
> + objnode = kmem_cache_alloc(zcache_objnode_cache,
> + ZCACHE_GFP_MASK);
> + if (unlikely(objnode == NULL)) {
> + zcache_failed_alloc++;
> + goto unlock_out;
> + }
> + preempt_disable();
> + kp = &__get_cpu_var(zcache_preloads);
> + if (kp->nr < ARRAY_SIZE(kp->objnodes))
> + kp->objnodes[kp->nr++] = objnode;
> + else
> + kmem_cache_free(zcache_objnode_cache, objnode);
> + }
> + preempt_enable_no_resched();
> + obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
> + if (unlikely(obj == NULL)) {
> + zcache_failed_alloc++;
> + goto unlock_out;
> + }
> + page = (void *)__get_free_page(ZCACHE_GFP_MASK);
> + if (unlikely(page == NULL)) {
> + zcache_failed_get_free_pages++;
> + kmem_cache_free(zcache_obj_cache, obj);
> + goto unlock_out;
> + }
> + preempt_disable();
> + kp = &__get_cpu_var(zcache_preloads);
> + if (kp->obj == NULL)
> + kp->obj = obj;
> + else
> + kmem_cache_free(zcache_obj_cache, obj);
> + if (kp->page == NULL)
> + kp->page = page;
> + else
> + free_page((unsigned long)page);
> + ret = 0;
> +unlock_out:
> + spin_unlock(&zcache_direct_reclaim_lock);
> +out:
> + return ret;
> +}
> +
> +static void *zcache_get_free_page(void)
> +{
> + struct zcache_preload *kp;
> + void *page;
> +
> + kp = &__get_cpu_var(zcache_preloads);
> + page = kp->page;
> + BUG_ON(page == NULL);
> + kp->page = NULL;
> + return page;
> +}
> +
> +static void zcache_free_page(void *p)
> +{
> + free_page((unsigned long)p);
> +}
> +
> +/*
> + * zcache implementation for tmem host ops
> + */
> +
> +static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
> +{
> + struct tmem_objnode *objnode = NULL;
> + unsigned long count;
> + struct zcache_preload *kp;
> +
> + kp = &__get_cpu_var(zcache_preloads);
> + if (kp->nr <= 0)
> + goto out;
> + objnode = kp->objnodes[kp->nr - 1];
> + BUG_ON(objnode == NULL);
> + kp->objnodes[kp->nr - 1] = NULL;
> + kp->nr--;
> + count = atomic_inc_return(&zcache_curr_objnode_count);
> + if (count > zcache_curr_objnode_count_max)
> + zcache_curr_objnode_count_max = count;
> +out:
> + return objnode;
> +}
> +
> +static void zcache_objnode_free(struct tmem_objnode *objnode,
> + struct tmem_pool *pool)
> +{
> + atomic_dec(&zcache_curr_objnode_count);
> + BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0);
> + kmem_cache_free(zcache_objnode_cache, objnode);
> +}
> +
> +static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
> +{
> + struct tmem_obj *obj = NULL;
> + unsigned long count;
> + struct zcache_preload *kp;
> +
> + kp = &__get_cpu_var(zcache_preloads);
> + obj = kp->obj;
> + BUG_ON(obj == NULL);
> + kp->obj = NULL;
> + count = atomic_inc_return(&zcache_curr_obj_count);
> + if (count > zcache_curr_obj_count_max)
> + zcache_curr_obj_count_max = count;
> + return obj;
> +}
> +
> +static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
> +{
> + atomic_dec(&zcache_curr_obj_count);
> + BUG_ON(atomic_read(&zcache_curr_obj_count) < 0);
> + kmem_cache_free(zcache_obj_cache, obj);
> +}
> +
> +static struct tmem_hostops zcache_hostops = {
> + .obj_alloc = zcache_obj_alloc,
> + .obj_free = zcache_obj_free,
> + .objnode_alloc = zcache_objnode_alloc,
> + .objnode_free = zcache_objnode_free,
> +};
> +
> +/*
> + * zcache implementations for PAM page descriptor ops
> + */
> +
> +static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0);
> +static unsigned long zcache_curr_eph_pampd_count_max;
> +static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0);
> +static unsigned long zcache_curr_pers_pampd_count_max;
> +
> +/* forward reference */
> +static int zcache_compress(struct page *from, void **out_va, size_t *out_len);
> +
> +static void *zcache_pampd_create(struct tmem_pool *pool, struct tmem_oid *oid,
> + uint32_t index, struct page *page)
> +{
> + void *pampd = NULL, *cdata;
> + size_t clen;
> + int ret;
> + bool ephemeral = is_ephemeral(pool);
> + unsigned long count;
> +
> + if (ephemeral) {
> + ret = zcache_compress(page, &cdata, &clen);
> + if (ret == 0)
> +
> + goto out;
> + if (clen == 0 || clen > zbud_max_buddy_size()) {
> + zcache_compress_poor++;
> + goto out;
> + }
> + pampd = (void *)zbud_create(pool->pool_id, oid, index,
> + page, cdata, clen);
> + if (pampd != NULL) {
> + count = atomic_inc_return(&zcache_curr_eph_pampd_count);
> + if (count > zcache_curr_eph_pampd_count_max)
> + zcache_curr_eph_pampd_count_max = count;
> + }
> + } else {
> + /*
> + * FIXME: This is all the "policy" there is for now.
> + * 3/4 totpages should allow ~37% of RAM to be filled with
> + * compressed frontswap pages
> + */
> + if (atomic_read(&zcache_curr_pers_pampd_count) >
> + 3 * totalram_pages / 4)
> + goto out;
> + ret = zcache_compress(page, &cdata, &clen);
> + if (ret == 0)
> + goto out;
> + if (clen > zv_max_page_size) {
> + zcache_compress_poor++;
> + goto out;
> + }
> + pampd = (void *)zv_create(zcache_client.xvpool, pool->pool_id,
> + oid, index, cdata, clen);
> + if (pampd == NULL)
> + goto out;
> + count = atomic_inc_return(&zcache_curr_pers_pampd_count);
> + if (count > zcache_curr_pers_pampd_count_max)
> + zcache_curr_pers_pampd_count_max = count;
> + }
> +out:
> + return pampd;
> +}
> +
> +/*
> + * fill the pageframe corresponding to the struct page with the data
> + * from the passed pampd
> + */
> +static int zcache_pampd_get_data(struct page *page, void *pampd,
> + struct tmem_pool *pool)
> +{
> + int ret = 0;
> +
> + if (is_ephemeral(pool))
> + ret = zbud_decompress(page, pampd);
> + else
> + zv_decompress(page, pampd);
> + return ret;
> +}
> +
> +/*
> + * free the pampd and remove it from any zcache lists
> + * pampd must no longer be pointed to from any tmem data structures!
> + */
> +static void zcache_pampd_free(void *pampd, struct tmem_pool *pool)
> +{
> + if (is_ephemeral(pool)) {
> + zbud_free_and_delist((struct zbud_hdr *)pampd);
> + atomic_dec(&zcache_curr_eph_pampd_count);
> + BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0);
> + } else {
> + zv_free(zcache_client.xvpool, (struct zv_hdr *)pampd);
> + atomic_dec(&zcache_curr_pers_pampd_count);
> + BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0);
> + }
> +}
> +
> +static struct tmem_pamops zcache_pamops = {
> + .create = zcache_pampd_create,
> + .get_data = zcache_pampd_get_data,
> + .free = zcache_pampd_free,
> +};
> +
> +/*
> + * zcache compression/decompression and related per-cpu stuff
> + */
> +
> +#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS
> +#define LZO_DSTMEM_PAGE_ORDER 1
> +static DEFINE_PER_CPU(unsigned char *, zcache_workmem);
> +static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
> +
> +static int zcache_compress(struct page *from, void **out_va, size_t *out_len)
> +{
> + int ret = 0;
> + unsigned char *dmem = __get_cpu_var(zcache_dstmem);
> + unsigned char *wmem = __get_cpu_var(zcache_workmem);
> + char *from_va;
> +
> + BUG_ON(!irqs_disabled());
> + if (unlikely(dmem == NULL || wmem == NULL))
> + goto out; /* no buffer, so can't compress */
> + from_va = kmap_atomic(from, KM_USER0);
> + mb();
> + ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem);
> + BUG_ON(ret != LZO_E_OK);
> + *out_va = dmem;
> + kunmap_atomic(from_va, KM_USER0);
> + ret = 1;
> +out:
> + return ret;
> +}
> +
> +
> +static int zcache_cpu_notifier(struct notifier_block *nb,
> + unsigned long action, void *pcpu)
> +{
> + int cpu = (long)pcpu;
> + struct zcache_preload *kp;
> +
> + switch (action) {
> + case CPU_UP_PREPARE:
> + per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
> + GFP_KERNEL | __GFP_REPEAT,
> + LZO_DSTMEM_PAGE_ORDER),
> + per_cpu(zcache_workmem, cpu) =
> + kzalloc(LZO1X_MEM_COMPRESS,
> + GFP_KERNEL | __GFP_REPEAT);
> + break;
> + case CPU_DEAD:
> + case CPU_UP_CANCELED:
> + free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
> + LZO_DSTMEM_PAGE_ORDER);
> + per_cpu(zcache_dstmem, cpu) = NULL;
> + kfree(per_cpu(zcache_workmem, cpu));
> + per_cpu(zcache_workmem, cpu) = NULL;
> + kp = &per_cpu(zcache_preloads, cpu);
> + while (kp->nr) {
> + kmem_cache_free(zcache_objnode_cache,
> + kp->objnodes[kp->nr - 1]);
> + kp->objnodes[kp->nr - 1] = NULL;
> + kp->nr--;
> + }
> + kmem_cache_free(zcache_obj_cache, kp->obj);
> + free_page((unsigned long)kp->page);
> + break;
> + default:
> + break;
> + }
> + return NOTIFY_OK;
> +}
> +
> +static struct notifier_block zcache_cpu_notifier_block = {
> + .notifier_call = zcache_cpu_notifier
> +};
> +
> +#ifdef CONFIG_SYSFS
> +#define ZCACHE_SYSFS_RO(_name) \
> + static ssize_t zcache_##_name##_show(struct kobject *kobj, \
> + struct kobj_attribute *attr, char *buf) \
> + { \
> + return sprintf(buf, "%lu\n", zcache_##_name); \
> + } \
> + static struct kobj_attribute zcache_##_name##_attr = { \
> + .attr = { .name = __stringify(_name), .mode = 0444 }, \
> + .show = zcache_##_name##_show, \
> + }
> +
> +#define ZCACHE_SYSFS_RO_ATOMIC(_name) \
> + static ssize_t zcache_##_name##_show(struct kobject *kobj, \
> + struct kobj_attribute *attr, char *buf) \
> + { \
> + return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \
> + } \
> + static struct kobj_attribute zcache_##_name##_attr = { \
> + .attr = { .name = __stringify(_name), .mode = 0444 }, \
> + .show = zcache_##_name##_show, \
> + }
> +
> +#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \
> + static ssize_t zcache_##_name##_show(struct kobject *kobj, \
> + struct kobj_attribute *attr, char *buf) \
> + { \
> + return _func(buf); \
> + } \
> + static struct kobj_attribute zcache_##_name##_attr = { \
> + .attr = { .name = __stringify(_name), .mode = 0444 }, \
> + .show = zcache_##_name##_show, \
> + }
> +
> +ZCACHE_SYSFS_RO(curr_obj_count_max);
> +ZCACHE_SYSFS_RO(curr_objnode_count_max);
> +ZCACHE_SYSFS_RO(flush_total);
> +ZCACHE_SYSFS_RO(flush_found);
> +ZCACHE_SYSFS_RO(flobj_total);
> +ZCACHE_SYSFS_RO(flobj_found);
> +ZCACHE_SYSFS_RO(failed_eph_puts);
> +ZCACHE_SYSFS_RO(failed_pers_puts);
> +ZCACHE_SYSFS_RO(zbud_curr_zbytes);
> +ZCACHE_SYSFS_RO(zbud_cumul_zpages);
> +ZCACHE_SYSFS_RO(zbud_cumul_zbytes);
> +ZCACHE_SYSFS_RO(zbud_buddied_count);
> +ZCACHE_SYSFS_RO(zbpg_unused_list_count);
> +ZCACHE_SYSFS_RO(evicted_raw_pages);
> +ZCACHE_SYSFS_RO(evicted_unbuddied_pages);
> +ZCACHE_SYSFS_RO(evicted_buddied_pages);
> +ZCACHE_SYSFS_RO(failed_get_free_pages);
> +ZCACHE_SYSFS_RO(failed_alloc);
> +ZCACHE_SYSFS_RO(put_to_flush);
> +ZCACHE_SYSFS_RO(aborted_preload);
> +ZCACHE_SYSFS_RO(aborted_shrink);
> +ZCACHE_SYSFS_RO(compress_poor);
> +ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages);
> +ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages);
> +ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count);
> +ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count);
> +ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts,
> + zbud_show_unbuddied_list_counts);
> +ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts,
> + zbud_show_cumul_chunk_counts);
> +
> +static struct attribute *zcache_attrs[] = {
> + &zcache_curr_obj_count_attr.attr,
> + &zcache_curr_obj_count_max_attr.attr,
> + &zcache_curr_objnode_count_attr.attr,
> + &zcache_curr_objnode_count_max_attr.attr,
> + &zcache_flush_total_attr.attr,
> + &zcache_flobj_total_attr.attr,
> + &zcache_flush_found_attr.attr,
> + &zcache_flobj_found_attr.attr,
> + &zcache_failed_eph_puts_attr.attr,
> + &zcache_failed_pers_puts_attr.attr,
> + &zcache_compress_poor_attr.attr,
> + &zcache_zbud_curr_raw_pages_attr.attr,
> + &zcache_zbud_curr_zpages_attr.attr,
> + &zcache_zbud_curr_zbytes_attr.attr,
> + &zcache_zbud_cumul_zpages_attr.attr,
> + &zcache_zbud_cumul_zbytes_attr.attr,
> + &zcache_zbud_buddied_count_attr.attr,
> + &zcache_zbpg_unused_list_count_attr.attr,
> + &zcache_evicted_raw_pages_attr.attr,
> + &zcache_evicted_unbuddied_pages_attr.attr,
> + &zcache_evicted_buddied_pages_attr.attr,
> + &zcache_failed_get_free_pages_attr.attr,
> + &zcache_failed_alloc_attr.attr,
> + &zcache_put_to_flush_attr.attr,
> + &zcache_aborted_preload_attr.attr,
> + &zcache_aborted_shrink_attr.attr,
> + &zcache_zbud_unbuddied_list_counts_attr.attr,
> + &zcache_zbud_cumul_chunk_counts_attr.attr,
> + NULL,
> +};
> +
> +static struct attribute_group zcache_attr_group = {
> + .attrs = zcache_attrs,
> + .name = "zcache",
> +};
> +
> +#endif /* CONFIG_SYSFS */
> +/*
> + * When zcache is disabled ("frozen"), pools can be created and destroyed,
> + * but all puts (and thus all other operations that require memory allocation)
> + * must fail. If zcache is unfrozen, accepts puts, then frozen again,
> + * data consistency requires all puts while frozen to be converted into
> + * flushes.
> + */
> +static bool zcache_freeze;
> +
> +/*
> + * zcache shrinker interface (only useful for ephemeral pages, so zbud only)
> + */
> +static int shrink_zcache_memory(struct shrinker *shrink,
> + struct shrink_control *sc)
> +{
> + int ret = -1;
> + int nr = sc->nr_to_scan;
> + gfp_t gfp_mask = sc->gfp_mask;
> +
> + if (nr >= 0) {
> + if (!(gfp_mask & __GFP_FS))
> + /* does this case really need to be skipped? */
> + goto out;
> + if (spin_trylock(&zcache_direct_reclaim_lock)) {
> + zbud_evict_pages(nr);
> + spin_unlock(&zcache_direct_reclaim_lock);
> + } else
> + zcache_aborted_shrink++;
> + }
> + ret = (int)atomic_read(&zcache_zbud_curr_raw_pages);
> +out:
> + return ret;
> +}
> +
> +static struct shrinker zcache_shrinker = {
> + .shrink = shrink_zcache_memory,
> + .seeks = DEFAULT_SEEKS,
> +};
> +
> +/*
> + * zcache shims between cleancache/frontswap ops and tmem
> + */
> +
> +static int zcache_put_page(int pool_id, struct tmem_oid *oidp,
> + uint32_t index, struct page *page)
> +{
> + struct tmem_pool *pool;
> + int ret = -1;
> +
> + BUG_ON(!irqs_disabled());
> + pool = zcache_get_pool_by_id(pool_id);
> + if (unlikely(pool == NULL))
> + goto out;
> + if (!zcache_freeze && zcache_do_preload(pool) == 0) {
> + /* preload does preempt_disable on success */
> + ret = tmem_put(pool, oidp, index, page);
> + if (ret < 0) {
> + if (is_ephemeral(pool))
> + zcache_failed_eph_puts++;
> + else
> + zcache_failed_pers_puts++;
> + }
> + zcache_put_pool(pool);
> + preempt_enable_no_resched();
> + } else {
> + zcache_put_to_flush++;
> + if (atomic_read(&pool->obj_count) > 0)
> + /* the put fails whether the flush succeeds or not */
> + (void)tmem_flush_page(pool, oidp, index);
> + zcache_put_pool(pool);
> + }
> +out:
> + return ret;
> +}
> +
> +static int zcache_get_page(int pool_id, struct tmem_oid *oidp,
> + uint32_t index, struct page *page)
> +{
> + struct tmem_pool *pool;
> + int ret = -1;
> + unsigned long flags;
> +
> + local_irq_save(flags);
> + pool = zcache_get_pool_by_id(pool_id);
> + if (likely(pool != NULL)) {
> + if (atomic_read(&pool->obj_count) > 0)
> + ret = tmem_get(pool, oidp, index, page);
> + zcache_put_pool(pool);
> + }
> + local_irq_restore(flags);
> + return ret;
> +}
> +
> +static int zcache_flush_page(int pool_id, struct tmem_oid *oidp, uint32_t index)
> +{
> + struct tmem_pool *pool;
> + int ret = -1;
> + unsigned long flags;
> +
> + local_irq_save(flags);
> + zcache_flush_total++;
> + pool = zcache_get_pool_by_id(pool_id);
> + if (likely(pool != NULL)) {
> + if (atomic_read(&pool->obj_count) > 0)
> + ret = tmem_flush_page(pool, oidp, index);
> + zcache_put_pool(pool);
> + }
> + if (ret >= 0)
> + zcache_flush_found++;
> + local_irq_restore(flags);
> + return ret;
> +}
> +
> +static int zcache_flush_object(int pool_id, struct tmem_oid *oidp)
> +{
> + struct tmem_pool *pool;
> + int ret = -1;
> + unsigned long flags;
> +
> + local_irq_save(flags);
> + zcache_flobj_total++;
> + pool = zcache_get_pool_by_id(pool_id);
> + if (likely(pool != NULL)) {
> + if (atomic_read(&pool->obj_count) > 0)
> + ret = tmem_flush_object(pool, oidp);
> + zcache_put_pool(pool);
> + }
> + if (ret >= 0)
> + zcache_flobj_found++;
> + local_irq_restore(flags);
> + return ret;
> +}
> +
> +static int zcache_destroy_pool(int pool_id)
> +{
> + struct tmem_pool *pool = NULL;
> + int ret = -1;
> +
> + if (pool_id < 0)
> + goto out;
> + pool = zcache_client.tmem_pools[pool_id];
> + if (pool == NULL)
> + goto out;
> + zcache_client.tmem_pools[pool_id] = NULL;
> + /* wait for pool activity on other cpus to quiesce */
> + while (atomic_read(&pool->refcount) != 0)
> + ;
> + local_bh_disable();
> + ret = tmem_destroy_pool(pool);
> + local_bh_enable();
> + kfree(pool);
> + pr_info("zcache: destroyed pool id=%d\n", pool_id);
> +out:
> + return ret;
> +}
> +
> +static int zcache_new_pool(uint32_t flags)
> +{
> + int poolid = -1;
> + struct tmem_pool *pool;
> +
> + pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL);
> + if (pool == NULL) {
> + pr_info("zcache: pool creation failed: out of memory\n");
> + goto out;
> + }
> +
> + for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++)
> + if (zcache_client.tmem_pools[poolid] == NULL)
> + break;
> + if (poolid >= MAX_POOLS_PER_CLIENT) {
> + pr_info("zcache: pool creation failed: max exceeded\n");
> + kfree(pool);
> + poolid = -1;
> + goto out;
> + }
> + atomic_set(&pool->refcount, 0);
> + pool->client = &zcache_client;
> + pool->pool_id = poolid;
> + tmem_new_pool(pool, flags);
> + zcache_client.tmem_pools[poolid] = pool;
> + pr_info("zcache: created %s tmem pool, id=%d\n",
> + flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
> + poolid);
> +out:
> + return poolid;
> +}
> +
> +/**********
> + * Two kernel functionalities currently can be layered on top of tmem.
> + * These are "cleancache" which is used as a second-chance cache for clean
> + * page cache pages; and "frontswap" which is used for swap pages
> + * to avoid writes to disk. A generic "shim" is provided here for each
> + * to translate in-kernel semantics to zcache semantics.
> + */
> +
> +#ifdef CONFIG_CLEANCACHE
> +static void zcache_cleancache_put_page(int pool_id,
> + struct cleancache_filekey key,
> + pgoff_t index, struct page *page)
> +{
> + u32 ind = (u32) index;
> + struct tmem_oid oid = *(struct tmem_oid *)&key;
> +
> + if (likely(ind == index))
> + (void)zcache_put_page(pool_id, &oid, index, page);
> +}
> +
> +static int zcache_cleancache_get_page(int pool_id,
> + struct cleancache_filekey key,
> + pgoff_t index, struct page *page)
> +{
> + u32 ind = (u32) index;
> + struct tmem_oid oid = *(struct tmem_oid *)&key;
> + int ret = -1;
> +
> + if (likely(ind == index))
> + ret = zcache_get_page(pool_id, &oid, index, page);
> + return ret;
> +}
> +
> +static void zcache_cleancache_flush_page(int pool_id,
> + struct cleancache_filekey key,
> + pgoff_t index)
> +{
> + u32 ind = (u32) index;
> + struct tmem_oid oid = *(struct tmem_oid *)&key;
> +
> + if (likely(ind == index))
> + (void)zcache_flush_page(pool_id, &oid, ind);
> +}
> +
> +static void zcache_cleancache_flush_inode(int pool_id,
> + struct cleancache_filekey key)
> +{
> + struct tmem_oid oid = *(struct tmem_oid *)&key;
> +
> + (void)zcache_flush_object(pool_id, &oid);
> +}
> +
> +static void zcache_cleancache_flush_fs(int pool_id)
> +{
> + if (pool_id >= 0)
> + (void)zcache_destroy_pool(pool_id);
> +}
> +
> +static int zcache_cleancache_init_fs(size_t pagesize)
> +{
> + BUG_ON(sizeof(struct cleancache_filekey) !=
> + sizeof(struct tmem_oid));
> + BUG_ON(pagesize != PAGE_SIZE);
> + return zcache_new_pool(0);
> +}
> +
> +static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
> +{
> + /* shared pools are unsupported and map to private */
> + BUG_ON(sizeof(struct cleancache_filekey) !=
> + sizeof(struct tmem_oid));
> + BUG_ON(pagesize != PAGE_SIZE);
> + return zcache_new_pool(0);
> +}
> +
> +static struct cleancache_ops zcache_cleancache_ops = {
> + .put_page = zcache_cleancache_put_page,
> + .get_page = zcache_cleancache_get_page,
> + .flush_page = zcache_cleancache_flush_page,
> + .flush_inode = zcache_cleancache_flush_inode,
> + .flush_fs = zcache_cleancache_flush_fs,
> + .init_shared_fs = zcache_cleancache_init_shared_fs,
> + .init_fs = zcache_cleancache_init_fs
> +};
> +
> +struct cleancache_ops zcache_cleancache_register_ops(void)
> +{
> + struct cleancache_ops old_ops =
> + cleancache_register_ops(&zcache_cleancache_ops);
> +
> + return old_ops;
> +}
> +#endif
> +
> +#ifdef CONFIG_FRONTSWAP
> +/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
> +static int zcache_frontswap_poolid = -1;
> +
> +/*
> + * Swizzling increases objects per swaptype, increasing tmem concurrency
> + * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
> + */
> +#define SWIZ_BITS 4
> +#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
> +#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
> +#define iswiz(_ind) (_ind >> SWIZ_BITS)
> +
> +static inline struct tmem_oid oswiz(unsigned type, u32 ind)
> +{
> + struct tmem_oid oid = { .oid = { 0 } };
> + oid.oid[0] = _oswiz(type, ind);
> + return oid;
> +}
> +
> +static int zcache_frontswap_put_page(unsigned type, pgoff_t offset,
> + struct page *page)
> +{
> + u64 ind64 = (u64)offset;
> + u32 ind = (u32)offset;
> + struct tmem_oid oid = oswiz(type, ind);
> + int ret = -1;
> + unsigned long flags;
> +
> + BUG_ON(!PageLocked(page));
> + if (likely(ind64 == ind)) {
> + local_irq_save(flags);
> + ret = zcache_put_page(zcache_frontswap_poolid, &oid,
> + iswiz(ind), page);
> + local_irq_restore(flags);
> + }
> + return ret;
> +}
> +
> +/* returns 0 if the page was successfully gotten from frontswap, -1 if
> + * was not present (should never happen!) */
> +static int zcache_frontswap_get_page(unsigned type, pgoff_t offset,
> + struct page *page)
> +{
> + u64 ind64 = (u64)offset;
> + u32 ind = (u32)offset;
> + struct tmem_oid oid = oswiz(type, ind);
> + int ret = -1;
> +
> + BUG_ON(!PageLocked(page));
> + if (likely(ind64 == ind))
> + ret = zcache_get_page(zcache_frontswap_poolid, &oid,
> + iswiz(ind), page);
> + return ret;
> +}
> +
> +/* flush a single page from frontswap */
> +static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
> +{
> + u64 ind64 = (u64)offset;
> + u32 ind = (u32)offset;
> + struct tmem_oid oid = oswiz(type, ind);
> +
> + if (likely(ind64 == ind))
> + (void)zcache_flush_page(zcache_frontswap_poolid, &oid,
> + iswiz(ind));
> +}
> +
> +/* flush all pages from the passed swaptype */
> +static void zcache_frontswap_flush_area(unsigned type)
> +{
> + struct tmem_oid oid;
> + int ind;
> +
> + for (ind = SWIZ_MASK; ind >= 0; ind--) {
> + oid = oswiz(type, ind);
> + (void)zcache_flush_object(zcache_frontswap_poolid, &oid);
> + }
> +}
> +
> +static void zcache_frontswap_init(unsigned ignored)
> +{
> + /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
> + if (zcache_frontswap_poolid < 0)
> + zcache_frontswap_poolid = zcache_new_pool(TMEM_POOL_PERSIST);
> +}
> +
> +static struct frontswap_ops zcache_frontswap_ops = {
> + .put_page = zcache_frontswap_put_page,
> + .get_page = zcache_frontswap_get_page,
> + .flush_page = zcache_frontswap_flush_page,
> + .flush_area = zcache_frontswap_flush_area,
> + .init = zcache_frontswap_init
> +};
> +
> +struct frontswap_ops zcache_frontswap_register_ops(void)
> +{
> + struct frontswap_ops old_ops =
> + frontswap_register_ops(&zcache_frontswap_ops);
> +
> + return old_ops;
> +}
> +#endif
> +
> +/*
> + * zcache initialization
> + * NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR
> + * NOTHING HAPPENS!
> + */
> +
> +static int zcache_enabled;
> +
> +static int __init enable_zcache(char *s)
> +{
> + zcache_enabled = 1;
> + return 1;
> +}
> +__setup("zcache", enable_zcache);
> +
> +/* allow independent dynamic disabling of cleancache and frontswap */
> +
> +static int use_cleancache = 1;
> +
> +static int __init no_cleancache(char *s)
> +{
> + use_cleancache = 0;
> + return 1;
> +}
> +
> +__setup("nocleancache", no_cleancache);
> +
> +static int use_frontswap = 1;
> +
> +static int __init no_frontswap(char *s)
> +{
> + use_frontswap = 0;
> + return 1;
> +}
> +
> +__setup("nofrontswap", no_frontswap);
> +
> +static int __init zcache_init(void)
> +{
> +#ifdef CONFIG_SYSFS
> + int ret = 0;
> +
> + ret = sysfs_create_group(mm_kobj, &zcache_attr_group);
> + if (ret) {
> + pr_err("zcache: can't create sysfs\n");
> + goto out;
> + }
> +#endif /* CONFIG_SYSFS */
> +#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP)
> + if (zcache_enabled) {
> + unsigned int cpu;
> +
> + tmem_register_hostops(&zcache_hostops);
> + tmem_register_pamops(&zcache_pamops);
> + ret = register_cpu_notifier(&zcache_cpu_notifier_block);
> + if (ret) {
> + pr_err("zcache: can't register cpu notifier\n");
> + goto out;
> + }
> + for_each_online_cpu(cpu) {
> + void *pcpu = (void *)(long)cpu;
> + zcache_cpu_notifier(&zcache_cpu_notifier_block,
> + CPU_UP_PREPARE, pcpu);
> + }
> + }
> + zcache_objnode_cache = kmem_cache_create("zcache_objnode",
> + sizeof(struct tmem_objnode), 0, 0, NULL);
> + zcache_obj_cache = kmem_cache_create("zcache_obj",
> + sizeof(struct tmem_obj), 0, 0, NULL);
> +#endif
> +#ifdef CONFIG_CLEANCACHE
> + if (zcache_enabled && use_cleancache) {
> + struct cleancache_ops old_ops;
> +
> + zbud_init();
> + register_shrinker(&zcache_shrinker);
> + old_ops = zcache_cleancache_register_ops();
> + pr_info("zcache: cleancache enabled using kernel "
> + "transcendent memory and compression buddies\n");
> + if (old_ops.init_fs != NULL)
> + pr_warning("zcache: cleancache_ops overridden");
> + }
> +#endif
> +#ifdef CONFIG_FRONTSWAP
> + if (zcache_enabled && use_frontswap) {
> + struct frontswap_ops old_ops;
> +
> + zcache_client.xvpool = xv_create_pool();
> + if (zcache_client.xvpool == NULL) {
> + pr_err("zcache: can't create xvpool\n");
> + goto out;
> + }
> + old_ops = zcache_frontswap_register_ops();
> + pr_info("zcache: frontswap enabled using kernel "
> + "transcendent memory and xvmalloc\n");
> + if (old_ops.init != NULL)
> + pr_warning("ktmem: frontswap_ops overridden");
> + }
> +#endif
> +out:
> + return ret;
> +}
> +
> +module_init(zcache_init)
> --
> 1.7.4.1
>
> --
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