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Message-ID: <20150618152132.GA9633@cerebellum.local.variantweb.net>
Date: Thu, 18 Jun 2015 10:21:32 -0500
From: Seth Jennings <sjennings@...iantweb.net>
To: Dan Streetman <ddstreet@...e.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Linux-MM <linux-mm@...ck.org>,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] zswap: dynamic pool creation
On Wed, Jun 17, 2015 at 07:13:31PM -0400, Dan Streetman wrote:
> On Wed, Jun 10, 2015 at 4:54 PM, Dan Streetman <ddstreet@...e.org> wrote:
> > On Thu, Jun 4, 2015 at 8:13 AM, Dan Streetman <ddstreet@...e.org> wrote:
> >> On Thu, Jun 4, 2015 at 8:02 AM, Dan Streetman <ddstreet@...e.org> wrote:
> >>> Add dynamic creation of pools. Move the static crypto compression
> >>> per-cpu transforms into each pool. Add a pointer to zswap_entry to
> >>> the pool it's in.
> >>
> >> Seth, as far as the design, from your previous comments I assume you
> >> were thinking of maintaining separate lists of zpools and compressors?
> >> I do see how that will reduce duplication of zpools and compressors,
> >> but it also requires adding a new pointer to each zswap_entry, and
> >> increasing the amount of code to manage each list separately. And the
> >> most common case in zswap will be just a single zpool and compressor,
> >> not repeatedly changing params. What do you think?
> >
> > Any opinion on this patch? If you want, I can break it up so there's
> > a list of zpools and a list of compressors. Either the combined way
> > (this patch) or separate lists works for me, as long as the params are
> > changeable at runtime :-)
>
> You on vacation Seth? Let me know what direction you prefer for this...
I think it is as good as it can be. Complicated, but I don't know of a
way to make it less so if we want to be able to do this (which is a
separate discussion).
Seth
>
> >
> >
> >>
> >>>
> >>> This is required by a separate patch which enables changing the
> >>> zswap zpool and compressor params at runtime.
> >>>
> >>> Signed-off-by: Dan Streetman <ddstreet@...e.org>
> >>> ---
> >>> mm/zswap.c | 550 +++++++++++++++++++++++++++++++++++++++++++++----------------
> >>> 1 file changed, 408 insertions(+), 142 deletions(-)
> >>>
> >>> diff --git a/mm/zswap.c b/mm/zswap.c
> >>> index 2d5727b..fc93770 100644
> >>> --- a/mm/zswap.c
> >>> +++ b/mm/zswap.c
> >>> @@ -99,66 +99,19 @@ module_param_named(zpool, zswap_zpool_type, charp, 0444);
> >>> static struct zpool *zswap_pool;
> >>>
> >>> /*********************************
> >>> -* compression functions
> >>> +* data structures
> >>> **********************************/
> >>> -/* per-cpu compression transforms */
> >>> -static struct crypto_comp * __percpu *zswap_comp_pcpu_tfms;
> >>>
> >>> -enum comp_op {
> >>> - ZSWAP_COMPOP_COMPRESS,
> >>> - ZSWAP_COMPOP_DECOMPRESS
> >>> +struct zswap_pool {
> >>> + struct zpool *zpool;
> >>> + struct kref kref;
> >>> + struct list_head list;
> >>> + struct rcu_head rcu_head;
> >>> + struct notifier_block notifier;
> >>> + char tfm_name[CRYPTO_MAX_ALG_NAME];
> >>> + struct crypto_comp * __percpu *tfm;
> >>> };
> >>>
> >>> -static int zswap_comp_op(enum comp_op op, const u8 *src, unsigned int slen,
> >>> - u8 *dst, unsigned int *dlen)
> >>> -{
> >>> - struct crypto_comp *tfm;
> >>> - int ret;
> >>> -
> >>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, get_cpu());
> >>> - switch (op) {
> >>> - case ZSWAP_COMPOP_COMPRESS:
> >>> - ret = crypto_comp_compress(tfm, src, slen, dst, dlen);
> >>> - break;
> >>> - case ZSWAP_COMPOP_DECOMPRESS:
> >>> - ret = crypto_comp_decompress(tfm, src, slen, dst, dlen);
> >>> - break;
> >>> - default:
> >>> - ret = -EINVAL;
> >>> - }
> >>> -
> >>> - put_cpu();
> >>> - return ret;
> >>> -}
> >>> -
> >>> -static int __init zswap_comp_init(void)
> >>> -{
> >>> - if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> >>> - pr_info("%s compressor not available\n", zswap_compressor);
> >>> - /* fall back to default compressor */
> >>> - zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
> >>> - if (!crypto_has_comp(zswap_compressor, 0, 0))
> >>> - /* can't even load the default compressor */
> >>> - return -ENODEV;
> >>> - }
> >>> - pr_info("using %s compressor\n", zswap_compressor);
> >>> -
> >>> - /* alloc percpu transforms */
> >>> - zswap_comp_pcpu_tfms = alloc_percpu(struct crypto_comp *);
> >>> - if (!zswap_comp_pcpu_tfms)
> >>> - return -ENOMEM;
> >>> - return 0;
> >>> -}
> >>> -
> >>> -static void __init zswap_comp_exit(void)
> >>> -{
> >>> - /* free percpu transforms */
> >>> - free_percpu(zswap_comp_pcpu_tfms);
> >>> -}
> >>> -
> >>> -/*********************************
> >>> -* data structures
> >>> -**********************************/
> >>> /*
> >>> * struct zswap_entry
> >>> *
> >>> @@ -166,22 +119,24 @@ static void __init zswap_comp_exit(void)
> >>> * page within zswap.
> >>> *
> >>> * rbnode - links the entry into red-black tree for the appropriate swap type
> >>> + * offset - the swap offset for the entry. Index into the red-black tree.
> >>> * refcount - the number of outstanding reference to the entry. This is needed
> >>> * to protect against premature freeing of the entry by code
> >>> * concurrent calls to load, invalidate, and writeback. The lock
> >>> * for the zswap_tree structure that contains the entry must
> >>> * be held while changing the refcount. Since the lock must
> >>> * be held, there is no reason to also make refcount atomic.
> >>> - * offset - the swap offset for the entry. Index into the red-black tree.
> >>> - * handle - zpool allocation handle that stores the compressed page data
> >>> * length - the length in bytes of the compressed page data. Needed during
> >>> * decompression
> >>> + * pool - the zswap_pool the entry's data is in
> >>> + * handle - zpool allocation handle that stores the compressed page data
> >>> */
> >>> struct zswap_entry {
> >>> struct rb_node rbnode;
> >>> pgoff_t offset;
> >>> int refcount;
> >>> unsigned int length;
> >>> + struct zswap_pool *pool;
> >>> unsigned long handle;
> >>> };
> >>>
> >>> @@ -201,6 +156,44 @@ struct zswap_tree {
> >>>
> >>> static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
> >>>
> >>> +/* RCU-protected iteration */
> >>> +static LIST_HEAD(zswap_pools);
> >>> +/* protects zswap_pools list modification */
> >>> +static DEFINE_SPINLOCK(zswap_pools_lock);
> >>> +
> >>> +/*********************************
> >>> +* helpers and fwd declarations
> >>> +**********************************/
> >>> +
> >>> +#define zswap_pool_debug(msg, p) \
> >>> + pr_debug("%s pool %s/%s\n", msg, (p)->tfm_name, \
> >>> + zpool_get_type((p)->zpool))
> >>> +
> >>> +static int zswap_writeback_entry(struct zpool *pool, unsigned long handle);
> >>> +static int zswap_pool_get(struct zswap_pool *pool);
> >>> +static void zswap_pool_put(struct zswap_pool *pool);
> >>> +
> >>> +static bool zswap_is_full(void)
> >>> +{
> >>> + return totalram_pages * zswap_max_pool_percent / 100 <
> >>> + DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> >>> +}
> >>> +
> >>> +static void zswap_update_total_size(void)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> + u64 total = 0;
> >>> +
> >>> + rcu_read_lock();
> >>> +
> >>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> >>> + total += zpool_get_total_size(pool->zpool);
> >>> +
> >>> + rcu_read_unlock();
> >>> +
> >>> + zswap_pool_total_size = total;
> >>> +}
> >>> +
> >>> /*********************************
> >>> * zswap entry functions
> >>> **********************************/
> >>> @@ -294,10 +287,11 @@ static void zswap_rb_erase(struct rb_root *root, struct zswap_entry *entry)
> >>> */
> >>> static void zswap_free_entry(struct zswap_entry *entry)
> >>> {
> >>> - zpool_free(zswap_pool, entry->handle);
> >>> + zpool_free(entry->pool->zpool, entry->handle);
> >>> + zswap_pool_put(entry->pool);
> >>> zswap_entry_cache_free(entry);
> >>> atomic_dec(&zswap_stored_pages);
> >>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> >>> + zswap_update_total_size();
> >>> }
> >>>
> >>> /* caller must hold the tree lock */
> >>> @@ -339,35 +333,21 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
> >>> **********************************/
> >>> static DEFINE_PER_CPU(u8 *, zswap_dstmem);
> >>>
> >>> -static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> >>> +static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
> >>> {
> >>> - struct crypto_comp *tfm;
> >>> u8 *dst;
> >>>
> >>> switch (action) {
> >>> case CPU_UP_PREPARE:
> >>> - tfm = crypto_alloc_comp(zswap_compressor, 0, 0);
> >>> - if (IS_ERR(tfm)) {
> >>> - pr_err("can't allocate compressor transform\n");
> >>> - return NOTIFY_BAD;
> >>> - }
> >>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = tfm;
> >>> dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
> >>> if (!dst) {
> >>> pr_err("can't allocate compressor buffer\n");
> >>> - crypto_free_comp(tfm);
> >>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> >>> return NOTIFY_BAD;
> >>> }
> >>> per_cpu(zswap_dstmem, cpu) = dst;
> >>> break;
> >>> case CPU_DEAD:
> >>> case CPU_UP_CANCELED:
> >>> - tfm = *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu);
> >>> - if (tfm) {
> >>> - crypto_free_comp(tfm);
> >>> - *per_cpu_ptr(zswap_comp_pcpu_tfms, cpu) = NULL;
> >>> - }
> >>> dst = per_cpu(zswap_dstmem, cpu);
> >>> kfree(dst);
> >>> per_cpu(zswap_dstmem, cpu) = NULL;
> >>> @@ -378,43 +358,309 @@ static int __zswap_cpu_notifier(unsigned long action, unsigned long cpu)
> >>> return NOTIFY_OK;
> >>> }
> >>>
> >>> -static int zswap_cpu_notifier(struct notifier_block *nb,
> >>> - unsigned long action, void *pcpu)
> >>> +static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
> >>> + unsigned long action, void *pcpu)
> >>> {
> >>> - unsigned long cpu = (unsigned long)pcpu;
> >>> - return __zswap_cpu_notifier(action, cpu);
> >>> + return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
> >>> }
> >>>
> >>> -static struct notifier_block zswap_cpu_notifier_block = {
> >>> - .notifier_call = zswap_cpu_notifier
> >>> +static struct notifier_block zswap_dstmem_notifier = {
> >>> + .notifier_call = zswap_cpu_dstmem_notifier,
> >>> };
> >>>
> >>> -static int __init zswap_cpu_init(void)
> >>> +static int __init zswap_cpu_dstmem_init(void)
> >>> {
> >>> unsigned long cpu;
> >>>
> >>> cpu_notifier_register_begin();
> >>> for_each_online_cpu(cpu)
> >>> - if (__zswap_cpu_notifier(CPU_UP_PREPARE, cpu) != NOTIFY_OK)
> >>> + if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
> >>> + NOTIFY_BAD)
> >>> goto cleanup;
> >>> - __register_cpu_notifier(&zswap_cpu_notifier_block);
> >>> + __register_cpu_notifier(&zswap_dstmem_notifier);
> >>> cpu_notifier_register_done();
> >>> return 0;
> >>>
> >>> cleanup:
> >>> for_each_online_cpu(cpu)
> >>> - __zswap_cpu_notifier(CPU_UP_CANCELED, cpu);
> >>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> >>> cpu_notifier_register_done();
> >>> return -ENOMEM;
> >>> }
> >>>
> >>> +static void zswap_cpu_dstmem_destroy(void)
> >>> +{
> >>> + unsigned long cpu;
> >>> +
> >>> + cpu_notifier_register_begin();
> >>> + for_each_online_cpu(cpu)
> >>> + __zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
> >>> + __unregister_cpu_notifier(&zswap_dstmem_notifier);
> >>> + cpu_notifier_register_done();
> >>> +}
> >>> +
> >>> +static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
> >>> + unsigned long action, unsigned long cpu)
> >>> +{
> >>> + struct crypto_comp *tfm;
> >>> +
> >>> + switch (action) {
> >>> + case CPU_UP_PREPARE:
> >>> + if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
> >>> + break;
> >>> + tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
> >>> + if (IS_ERR_OR_NULL(tfm)) {
> >>> + pr_err("could not alloc crypto comp %s : %ld\n",
> >>> + pool->tfm_name, PTR_ERR(tfm));
> >>> + return NOTIFY_BAD;
> >>> + }
> >>> + *per_cpu_ptr(pool->tfm, cpu) = tfm;
> >>> + break;
> >>> + case CPU_DEAD:
> >>> + case CPU_UP_CANCELED:
> >>> + tfm = *per_cpu_ptr(pool->tfm, cpu);
> >>> + if (!IS_ERR_OR_NULL(tfm))
> >>> + crypto_free_comp(tfm);
> >>> + *per_cpu_ptr(pool->tfm, cpu) = NULL;
> >>> + break;
> >>> + default:
> >>> + break;
> >>> + }
> >>> + return NOTIFY_OK;
> >>> +}
> >>> +
> >>> +static int zswap_cpu_comp_notifier(struct notifier_block *nb,
> >>> + unsigned long action, void *pcpu)
> >>> +{
> >>> + unsigned long cpu = (unsigned long)pcpu;
> >>> + struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
> >>> +
> >>> + return __zswap_cpu_comp_notifier(pool, action, cpu);
> >>> +}
> >>> +
> >>> +static int zswap_cpu_comp_init(struct zswap_pool *pool)
> >>> +{
> >>> + unsigned long cpu;
> >>> +
> >>> + memset(&pool->notifier, 0, sizeof(pool->notifier));
> >>> + pool->notifier.notifier_call = zswap_cpu_comp_notifier;
> >>> +
> >>> + cpu_notifier_register_begin();
> >>> + for_each_online_cpu(cpu)
> >>> + if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
> >>> + NOTIFY_BAD)
> >>> + goto cleanup;
> >>> + __register_cpu_notifier(&pool->notifier);
> >>> + cpu_notifier_register_done();
> >>> + return 0;
> >>> +
> >>> +cleanup:
> >>> + for_each_online_cpu(cpu)
> >>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> >>> + cpu_notifier_register_done();
> >>> + return -ENOMEM;
> >>> +}
> >>> +
> >>> +static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
> >>> +{
> >>> + unsigned long cpu;
> >>> +
> >>> + cpu_notifier_register_begin();
> >>> + for_each_online_cpu(cpu)
> >>> + __zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
> >>> + __unregister_cpu_notifier(&pool->notifier);
> >>> + cpu_notifier_register_done();
> >>> +}
> >>> +
> >>> /*********************************
> >>> -* helpers
> >>> +* pool functions
> >>> **********************************/
> >>> -static bool zswap_is_full(void)
> >>> +
> >>> +static struct zswap_pool *__zswap_pool_current(void)
> >>> {
> >>> - return totalram_pages * zswap_max_pool_percent / 100 <
> >>> - DIV_ROUND_UP(zswap_pool_total_size, PAGE_SIZE);
> >>> + struct zswap_pool *pool;
> >>> +
> >>> + pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
> >>> + WARN_ON(!pool);
> >>> +
> >>> + return pool;
> >>> +}
> >>> +
> >>> +static struct zswap_pool *zswap_pool_current(void)
> >>> +{
> >>> + assert_spin_locked(&zswap_pools_lock);
> >>> +
> >>> + return __zswap_pool_current();
> >>> +}
> >>> +
> >>> +static struct zswap_pool *zswap_pool_current_get(void)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> +
> >>> + rcu_read_lock();
> >>> +
> >>> + pool = __zswap_pool_current();
> >>> + if (!pool || !zswap_pool_get(pool))
> >>> + pool = NULL;
> >>> +
> >>> + rcu_read_unlock();
> >>> +
> >>> + return pool;
> >>> +}
> >>> +
> >>> +static struct zswap_pool *zswap_pool_last_get(void)
> >>> +{
> >>> + struct zswap_pool *pool, *last = NULL;
> >>> +
> >>> + rcu_read_lock();
> >>> +
> >>> + list_for_each_entry_rcu(pool, &zswap_pools, list)
> >>> + last = pool;
> >>> + if (!WARN_ON(!last) && !zswap_pool_get(last))
> >>> + last = NULL;
> >>> +
> >>> + rcu_read_unlock();
> >>> +
> >>> + return last;
> >>> +}
> >>> +
> >>> +static struct zpool_ops zswap_zpool_ops = {
> >>> + .evict = zswap_writeback_entry
> >>> +};
> >>> +
> >>> +static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> +
> >>> + assert_spin_locked(&zswap_pools_lock);
> >>> +
> >>> + list_for_each_entry_rcu(pool, &zswap_pools, list) {
> >>> + if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
> >>> + continue;
> >>> + if (strncmp(zpool_get_type(pool->zpool), type,
> >>> + sizeof(zswap_zpool_type)))
> >>> + continue;
> >>> + /* if we can't get it, it's about to be destroyed */
> >>> + if (!zswap_pool_get(pool))
> >>> + continue;
> >>> + return pool;
> >>> + }
> >>> +
> >>> + return NULL;
> >>> +}
> >>> +
> >>> +static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> + gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> >>> +
> >>> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> >>> + if (!pool) {
> >>> + pr_err("pool alloc failed\n");
> >>> + return NULL;
> >>> + }
> >>> +
> >>> + pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
> >>> + if (!pool->zpool) {
> >>> + pr_err("%s zpool not available\n", type);
> >>> + goto error;
> >>> + }
> >>> + pr_debug("using %s zpool\n", zpool_get_type(pool->zpool));
> >>> +
> >>> + strlcpy(pool->tfm_name, compressor, sizeof(pool->tfm_name));
> >>> + pool->tfm = alloc_percpu(struct crypto_comp *);
> >>> + if (!pool->tfm) {
> >>> + pr_err("percpu alloc failed\n");
> >>> + goto error;
> >>> + }
> >>> +
> >>> + if (zswap_cpu_comp_init(pool))
> >>> + goto error;
> >>> + pr_debug("using %s compressor\n", pool->tfm_name);
> >>> +
> >>> + /* being the current pool takes 1 ref; this func expects the
> >>> + * caller to always add the new pool as the current pool
> >>> + */
> >>> + kref_init(&pool->kref);
> >>> + INIT_LIST_HEAD(&pool->list);
> >>> +
> >>> + zswap_pool_debug("created", pool);
> >>> +
> >>> + return pool;
> >>> +
> >>> +error:
> >>> + free_percpu(pool->tfm);
> >>> + if (pool->zpool)
> >>> + zpool_destroy_pool(pool->zpool);
> >>> + kfree(pool);
> >>> + return NULL;
> >>> +}
> >>> +
> >>> +static struct zswap_pool *__zswap_pool_create_fallback(void)
> >>> +{
> >>> + if (!crypto_has_comp(zswap_compressor, 0, 0)) {
> >>> + pr_err("compressor %s not available, using default %s\n",
> >>> + zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);
> >>> + strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,
> >>> + sizeof(zswap_compressor));
> >>> + }
> >>> + if (!zpool_has_pool(zswap_zpool_type)) {
> >>> + pr_err("zpool %s not available, using default %s\n",
> >>> + zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);
> >>> + strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,
> >>> + sizeof(zswap_zpool_type));
> >>> + }
> >>> +
> >>> + return zswap_pool_create(zswap_zpool_type, zswap_compressor);
> >>> +}
> >>> +
> >>> +static void zswap_pool_destroy(struct zswap_pool *pool)
> >>> +{
> >>> + zswap_pool_debug("destroying", pool);
> >>> +
> >>> + zswap_cpu_comp_destroy(pool);
> >>> + free_percpu(pool->tfm);
> >>> + zpool_destroy_pool(pool->zpool);
> >>> + kfree(pool);
> >>> +}
> >>> +
> >>> +static int __must_check zswap_pool_get(struct zswap_pool *pool)
> >>> +{
> >>> + return kref_get_unless_zero(&pool->kref);
> >>> +}
> >>> +
> >>> +static void __zswap_pool_release(struct rcu_head *head)
> >>> +{
> >>> + struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
> >>> +
> >>> + /* nobody should have been able to get a kref... */
> >>> + WARN_ON(kref_get_unless_zero(&pool->kref));
> >>> +
> >>> + /* pool is now off zswap_pools list and has no references. */
> >>> + zswap_pool_destroy(pool);
> >>> +}
> >>> +
> >>> +static void __zswap_pool_empty(struct kref *kref)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> +
> >>> + pool = container_of(kref, typeof(*pool), kref);
> >>> +
> >>> + spin_lock(&zswap_pools_lock);
> >>> +
> >>> + WARN_ON(pool == zswap_pool_current());
> >>> +
> >>> + list_del_rcu(&pool->list);
> >>> + call_rcu(&pool->rcu_head, __zswap_pool_release);
> >>> +
> >>> + spin_unlock(&zswap_pools_lock);
> >>> +}
> >>> +
> >>> +static void zswap_pool_put(struct zswap_pool *pool)
> >>> +{
> >>> + kref_put(&pool->kref, __zswap_pool_empty);
> >>> +}
> >>> +
> >>> }
> >>>
> >>> /*********************************
> >>> @@ -538,6 +784,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> >>> pgoff_t offset;
> >>> struct zswap_entry *entry;
> >>> struct page *page;
> >>> + struct crypto_comp *tfm;
> >>> u8 *src, *dst;
> >>> unsigned int dlen;
> >>> int ret;
> >>> @@ -578,13 +825,15 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
> >>> case ZSWAP_SWAPCACHE_NEW: /* page is locked */
> >>> /* decompress */
> >>> dlen = PAGE_SIZE;
> >>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> >>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> >>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> >>> dst = kmap_atomic(page);
> >>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src,
> >>> - entry->length, dst, &dlen);
> >>> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >>> + ret = crypto_comp_decompress(tfm, src, entry->length,
> >>> + dst, &dlen);
> >>> + put_cpu_ptr(entry->pool->tfm);
> >>> kunmap_atomic(dst);
> >>> - zpool_unmap_handle(zswap_pool, entry->handle);
> >>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> >>> BUG_ON(ret);
> >>> BUG_ON(dlen != PAGE_SIZE);
> >>>
> >>> @@ -633,6 +882,22 @@ end:
> >>> return ret;
> >>> }
> >>>
> >>> +static int zswap_shrink(void)
> >>> +{
> >>> + struct zswap_pool *pool;
> >>> + int ret;
> >>> +
> >>> + pool = zswap_pool_last_get();
> >>> + if (!pool)
> >>> + return -ENOENT;
> >>> +
> >>> + ret = zpool_shrink(pool->zpool, 1, NULL);
> >>> +
> >>> + zswap_pool_put(pool);
> >>> +
> >>> + return ret;
> >>> +}
> >>> +
> >>> /*********************************
> >>> * frontswap hooks
> >>> **********************************/
> >>> @@ -642,6 +907,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>> {
> >>> struct zswap_tree *tree = zswap_trees[type];
> >>> struct zswap_entry *entry, *dupentry;
> >>> + struct crypto_comp *tfm;
> >>> int ret;
> >>> unsigned int dlen = PAGE_SIZE, len;
> >>> unsigned long handle;
> >>> @@ -657,7 +923,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>> /* reclaim space if needed */
> >>> if (zswap_is_full()) {
> >>> zswap_pool_limit_hit++;
> >>> - if (zpool_shrink(zswap_pool, 1, NULL)) {
> >>> + if (zswap_shrink()) {
> >>> zswap_reject_reclaim_fail++;
> >>> ret = -ENOMEM;
> >>> goto reject;
> >>> @@ -672,33 +938,42 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>> goto reject;
> >>> }
> >>>
> >>> + /* if entry is successfully added, it keeps the reference */
> >>> + entry->pool = zswap_pool_current_get();
> >>> + if (!entry->pool) {
> >>> + ret = -EINVAL;
> >>> + goto freepage;
> >>> + }
> >>> +
> >>> /* compress */
> >>> dst = get_cpu_var(zswap_dstmem);
> >>> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >>> src = kmap_atomic(page);
> >>> - ret = zswap_comp_op(ZSWAP_COMPOP_COMPRESS, src, PAGE_SIZE, dst, &dlen);
> >>> + ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
> >>> kunmap_atomic(src);
> >>> + put_cpu_ptr(entry->pool->tfm);
> >>> if (ret) {
> >>> ret = -EINVAL;
> >>> - goto freepage;
> >>> + goto put_dstmem;
> >>> }
> >>>
> >>> /* store */
> >>> len = dlen + sizeof(struct zswap_header);
> >>> - ret = zpool_malloc(zswap_pool, len, __GFP_NORETRY | __GFP_NOWARN,
> >>> - &handle);
> >>> + ret = zpool_malloc(entry->pool->zpool, len,
> >>> + __GFP_NORETRY | __GFP_NOWARN, &handle);
> >>> if (ret == -ENOSPC) {
> >>> zswap_reject_compress_poor++;
> >>> - goto freepage;
> >>> + goto put_dstmem;
> >>> }
> >>> if (ret) {
> >>> zswap_reject_alloc_fail++;
> >>> - goto freepage;
> >>> + goto put_dstmem;
> >>> }
> >>> - zhdr = zpool_map_handle(zswap_pool, handle, ZPOOL_MM_RW);
> >>> + zhdr = zpool_map_handle(entry->pool->zpool, handle, ZPOOL_MM_RW);
> >>> zhdr->swpentry = swp_entry(type, offset);
> >>> buf = (u8 *)(zhdr + 1);
> >>> memcpy(buf, dst, dlen);
> >>> - zpool_unmap_handle(zswap_pool, handle);
> >>> + zpool_unmap_handle(entry->pool->zpool, handle);
> >>> put_cpu_var(zswap_dstmem);
> >>>
> >>> /* populate entry */
> >>> @@ -721,12 +996,14 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
> >>>
> >>> /* update stats */
> >>> atomic_inc(&zswap_stored_pages);
> >>> - zswap_pool_total_size = zpool_get_total_size(zswap_pool);
> >>> + zswap_update_total_size();
> >>>
> >>> return 0;
> >>>
> >>> -freepage:
> >>> +put_dstmem:
> >>> put_cpu_var(zswap_dstmem);
> >>> + zswap_pool_put(entry->pool);
> >>> +freepage:
> >>> zswap_entry_cache_free(entry);
> >>> reject:
> >>> return ret;
> >>> @@ -741,6 +1018,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> >>> {
> >>> struct zswap_tree *tree = zswap_trees[type];
> >>> struct zswap_entry *entry;
> >>> + struct crypto_comp *tfm;
> >>> u8 *src, *dst;
> >>> unsigned int dlen;
> >>> int ret;
> >>> @@ -757,13 +1035,14 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
> >>>
> >>> /* decompress */
> >>> dlen = PAGE_SIZE;
> >>> - src = (u8 *)zpool_map_handle(zswap_pool, entry->handle,
> >>> + src = (u8 *)zpool_map_handle(entry->pool->zpool, entry->handle,
> >>> ZPOOL_MM_RO) + sizeof(struct zswap_header);
> >>> dst = kmap_atomic(page);
> >>> - ret = zswap_comp_op(ZSWAP_COMPOP_DECOMPRESS, src, entry->length,
> >>> - dst, &dlen);
> >>> + tfm = *get_cpu_ptr(entry->pool->tfm);
> >>> + ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
> >>> + put_cpu_ptr(entry->pool->tfm);
> >>> kunmap_atomic(dst);
> >>> - zpool_unmap_handle(zswap_pool, entry->handle);
> >>> + zpool_unmap_handle(entry->pool->zpool, entry->handle);
> >>> BUG_ON(ret);
> >>>
> >>> spin_lock(&tree->lock);
> >>> @@ -816,10 +1095,6 @@ static void zswap_frontswap_invalidate_area(unsigned type)
> >>> zswap_trees[type] = NULL;
> >>> }
> >>>
> >>> -static struct zpool_ops zswap_zpool_ops = {
> >>> - .evict = zswap_writeback_entry
> >>> -};
> >>> -
> >>> static void zswap_frontswap_init(unsigned type)
> >>> {
> >>> struct zswap_tree *tree;
> >>> @@ -900,49 +1175,40 @@ static void __exit zswap_debugfs_exit(void) { }
> >>> **********************************/
> >>> static int __init init_zswap(void)
> >>> {
> >>> - gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN;
> >>> + struct zswap_pool *pool;
> >>>
> >>> - pr_info("loading zswap\n");
> >>> -
> >>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> >>> - &zswap_zpool_ops);
> >>> - if (!zswap_pool && strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {
> >>> - pr_info("%s zpool not available\n", zswap_zpool_type);
> >>> - zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
> >>> - zswap_pool = zpool_create_pool(zswap_zpool_type, "zswap", gfp,
> >>> - &zswap_zpool_ops);
> >>> - }
> >>> - if (!zswap_pool) {
> >>> - pr_err("%s zpool not available\n", zswap_zpool_type);
> >>> - pr_err("zpool creation failed\n");
> >>> - goto error;
> >>> - }
> >>> - pr_info("using %s pool\n", zswap_zpool_type);
> >>> + pr_info("loading\n");
> >>>
> >>> if (zswap_entry_cache_create()) {
> >>> pr_err("entry cache creation failed\n");
> >>> - goto cachefail;
> >>> + goto cache_fail;
> >>> }
> >>> - if (zswap_comp_init()) {
> >>> - pr_err("compressor initialization failed\n");
> >>> - goto compfail;
> >>> +
> >>> + if (zswap_cpu_dstmem_init()) {
> >>> + pr_err("dstmem alloc failed\n");
> >>> + goto dstmem_fail;
> >>> }
> >>> - if (zswap_cpu_init()) {
> >>> - pr_err("per-cpu initialization failed\n");
> >>> - goto pcpufail;
> >>> +
> >>> + pool = __zswap_pool_create_fallback();
> >>> + if (!pool) {
> >>> + pr_err("pool creation failed\n");
> >>> + goto pool_fail;
> >>> }
> >>> + pr_info("loaded using pool %s/%s\n", pool->tfm_name,
> >>> + zpool_get_type(pool->zpool));
> >>> +
> >>> + list_add(&pool->list, &zswap_pools);
> >>>
> >>> frontswap_register_ops(&zswap_frontswap_ops);
> >>> if (zswap_debugfs_init())
> >>> pr_warn("debugfs initialization failed\n");
> >>> return 0;
> >>> -pcpufail:
> >>> - zswap_comp_exit();
> >>> -compfail:
> >>> +
> >>> +pool_fail:
> >>> + zswap_cpu_dstmem_destroy();
> >>> +dstmem_fail:
> >>> zswap_entry_cache_destroy();
> >>> -cachefail:
> >>> - zpool_destroy_pool(zswap_pool);
> >>> -error:
> >>> +cache_fail:
> >>> return -ENOMEM;
> >>> }
> >>> /* must be late so crypto has time to come up */
> >>> --
> >>> 2.1.0
> >>>
>
> --
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