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Message-ID: <20070117135142.GA24866@in.ibm.com>
Date: Wed, 17 Jan 2007 19:21:42 +0530
From: Suparna Bhattacharya <suparna@...ibm.com>
To: Evgeniy Polyakov <johnpol@....mipt.ru>
Cc: David Miller <davem@...emloft.net>,
Ulrich Drepper <drepper@...hat.com>,
Andrew Morton <akpm@...l.org>, netdev <netdev@...r.kernel.org>,
Zach Brown <zach.brown@...cle.com>,
Christoph Hellwig <hch@...radead.org>,
Chase Venters <chase.venters@...entec.com>,
Johann Borck <johann.borck@...sedata.com>,
linux-kernel@...r.kernel.org, Jeff Garzik <jeff@...zik.org>,
Jamal Hadi Salim <hadi@...erus.ca>,
Ingo Molnar <mingo@...e.hu>, linux-fsdevel@...r.kernel.org
Subject: Re: [take33 10/10] kevent: Kevent based AIO (aio_sendfile()/aio_sendfile_path()).
Since you are implementing new APIs here, have you considered doing an
aio_sendfilev to be able to send a header with the data ?
Regards
Suparna
On Wed, Jan 17, 2007 at 09:30:35AM +0300, Evgeniy Polyakov wrote:
>
> Kevent based AIO (aio_sendfile()/aio_sendfile_path()).
>
> aio_sendfile()/aio_sendfile_path() contains of two major parts: AIO
> state machine and page processing code.
> The former is just a small subsystem, which allows to queue callback
> for theirs invocation in process' context on behalf of pool of kernel
> threads. It allows to queue caches of callbacks to the local thread
> or to any other specified. Each cache of callbacks is processed until
> there are callbacks in it, callbacks can requeue themselfs into the
> same cache.
>
> Real work is being done in page processing code - code which populates
> pages into VFS cache and then sends pages to the destination socket
> via ->sendpage(). Unlike previous aio_sendfile() implementation, new
> one does not require low-level filesystem specific callbacks (->get_block())
> at all, instead I extended struct address_space_operations to contain new
> member called ->aio_readpages(), which is exactly the same as ->readpage()
> (read: mpage_readpages()) except different BIO allocation and sumbission
> routines. I changed mpage_readpages() to provide mpage_alloc() and
> mpage_bio_submit() to the new function called __mpage_readpages(), which is
> exactly old mpage_readpages() with provided callback invocation instead of
> usage for old functions. mpage_readpages_aio() provides kevent specific
> callbacks, which calls old functions, but with different destructor callbacks,
> which are essentially the same, except that they reschedule AIO processing.
>
> aio_sendfile_path() is essentially aio_sendfile(), except that it takes
> source filename as parameter and returns opened file descriptor.
>
> Benchmark of the 100 1MB files transfer (files are in VFS already) using sync
> sendfile() against aio_sendfile_path() shows about 10MB/sec performance win
> (78 MB/s vs 66-72 MB/s over 1 Gb network, sendfile sending server is one-way
> AMD Athlong 64 3500+) for aio_sendfile_path().
>
> AIO state machine is a base for network AIO (which becomes
> quite trivial), but I will not start implementation until
> roadback of kevent as a whole and AIO implementation become more clear.
>
> Signed-off-by: Evgeniy Polyakov <johnpol@....mipt.ru>
>
> diff --git a/fs/bio.c b/fs/bio.c
> index 7618bcb..291e7e8 100644
> --- a/fs/bio.c
> +++ b/fs/bio.c
> @@ -120,7 +120,7 @@ void bio_free(struct bio *bio, struct bio_set *bio_set)
> /*
> * default destructor for a bio allocated with bio_alloc_bioset()
> */
> -static void bio_fs_destructor(struct bio *bio)
> +void bio_fs_destructor(struct bio *bio)
> {
> bio_free(bio, fs_bio_set);
> }
> diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
> index beaf25f..f08c957 100644
> --- a/fs/ext3/inode.c
> +++ b/fs/ext3/inode.c
> @@ -1650,6 +1650,13 @@ ext3_readpages(struct file *file, struct address_space *mapping,
> return mpage_readpages(mapping, pages, nr_pages, ext3_get_block);
> }
>
> +static int
> +ext3_readpages_aio(struct file *file, struct address_space *mapping,
> + struct list_head *pages, unsigned nr_pages, void *priv)
> +{
> + return mpage_readpages_aio(mapping, pages, nr_pages, ext3_get_block, priv);
> +}
> +
> static void ext3_invalidatepage(struct page *page, unsigned long offset)
> {
> journal_t *journal = EXT3_JOURNAL(page->mapping->host);
> @@ -1768,6 +1775,7 @@ static int ext3_journalled_set_page_dirty(struct page *page)
> }
>
> static const struct address_space_operations ext3_ordered_aops = {
> + .aio_readpages = ext3_readpages_aio,
> .readpage = ext3_readpage,
> .readpages = ext3_readpages,
> .writepage = ext3_ordered_writepage,
> diff --git a/fs/mpage.c b/fs/mpage.c
> index 692a3e5..e5ba44b 100644
> --- a/fs/mpage.c
> +++ b/fs/mpage.c
> @@ -102,7 +102,7 @@ static struct bio *mpage_bio_submit(int rw, struct bio *bio)
> static struct bio *
> mpage_alloc(struct block_device *bdev,
> sector_t first_sector, int nr_vecs,
> - gfp_t gfp_flags)
> + gfp_t gfp_flags, void *priv)
> {
> struct bio *bio;
>
> @@ -116,6 +116,7 @@ mpage_alloc(struct block_device *bdev,
> if (bio) {
> bio->bi_bdev = bdev;
> bio->bi_sector = first_sector;
> + bio->bi_private = priv;
> }
> return bio;
> }
> @@ -175,7 +176,10 @@ map_buffer_to_page(struct page *page, struct buffer_head *bh, int page_block)
> static struct bio *
> do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
> sector_t *last_block_in_bio, struct buffer_head *map_bh,
> - unsigned long *first_logical_block, get_block_t get_block)
> + unsigned long *first_logical_block, get_block_t get_block,
> + struct bio *(*alloc)(struct block_device *bdev, sector_t first_sector,
> + int nr_vecs, gfp_t gfp_flags, void *priv),
> + struct bio *(*submit)(int rw, struct bio *bio), void *priv)
> {
> struct inode *inode = page->mapping->host;
> const unsigned blkbits = inode->i_blkbits;
> @@ -302,25 +306,25 @@ do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
> * This page will go to BIO. Do we need to send this BIO off first?
> */
> if (bio && (*last_block_in_bio != blocks[0] - 1))
> - bio = mpage_bio_submit(READ, bio);
> + bio = submit(READ, bio);
>
> alloc_new:
> if (bio == NULL) {
> - bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
> + bio = alloc(bdev, blocks[0] << (blkbits - 9),
> min_t(int, nr_pages, bio_get_nr_vecs(bdev)),
> - GFP_KERNEL);
> + GFP_KERNEL, priv);
> if (bio == NULL)
> goto confused;
> }
>
> length = first_hole << blkbits;
> if (bio_add_page(bio, page, length, 0) < length) {
> - bio = mpage_bio_submit(READ, bio);
> + bio = submit(READ, bio);
> goto alloc_new;
> }
>
> if (buffer_boundary(map_bh) || (first_hole != blocks_per_page))
> - bio = mpage_bio_submit(READ, bio);
> + bio = submit(READ, bio);
> else
> *last_block_in_bio = blocks[blocks_per_page - 1];
> out:
> @@ -328,7 +332,7 @@ out:
>
> confused:
> if (bio)
> - bio = mpage_bio_submit(READ, bio);
> + bio = submit(READ, bio);
> if (!PageUptodate(page))
> block_read_full_page(page, get_block);
> else
> @@ -336,6 +340,48 @@ confused:
> goto out;
> }
>
> +int
> +__mpage_readpages(struct address_space *mapping, struct list_head *pages,
> + unsigned nr_pages, get_block_t get_block,
> + struct bio *(*alloc)(struct block_device *bdev, sector_t first_sector,
> + int nr_vecs, gfp_t gfp_flags, void *priv),
> + struct bio *(*submit)(int rw, struct bio *bio),
> + void *priv)
> +{
> + struct bio *bio = NULL;
> + unsigned page_idx;
> + sector_t last_block_in_bio = 0;
> + struct pagevec lru_pvec;
> + struct buffer_head map_bh;
> + unsigned long first_logical_block = 0;
> +
> + clear_buffer_mapped(&map_bh);
> + pagevec_init(&lru_pvec, 0);
> + for (page_idx = 0; page_idx < nr_pages; page_idx++) {
> + struct page *page = list_entry(pages->prev, struct page, lru);
> +
> + prefetchw(&page->flags);
> + list_del(&page->lru);
> + if (!add_to_page_cache(page, mapping,
> + page->index, GFP_KERNEL)) {
> + bio = do_mpage_readpage(bio, page,
> + nr_pages - page_idx,
> + &last_block_in_bio, &map_bh,
> + &first_logical_block,
> + get_block, alloc, submit, priv);
> + if (!pagevec_add(&lru_pvec, page))
> + __pagevec_lru_add(&lru_pvec);
> + } else {
> + page_cache_release(page);
> + }
> + }
> + pagevec_lru_add(&lru_pvec);
> + BUG_ON(!list_empty(pages));
> + if (bio)
> + submit(READ, bio);
> + return 0;
> +}
> +
> /**
> * mpage_readpages - populate an address space with some pages, and
> * start reads against them.
> @@ -386,40 +432,28 @@ int
> mpage_readpages(struct address_space *mapping, struct list_head *pages,
> unsigned nr_pages, get_block_t get_block)
> {
> - struct bio *bio = NULL;
> - unsigned page_idx;
> - sector_t last_block_in_bio = 0;
> - struct pagevec lru_pvec;
> - struct buffer_head map_bh;
> - unsigned long first_logical_block = 0;
> + return __mpage_readpages(mapping, pages, nr_pages, get_block,
> + mpage_alloc, mpage_bio_submit, NULL);
> +}
> +EXPORT_SYMBOL(mpage_readpages);
>
> - clear_buffer_mapped(&map_bh);
> - pagevec_init(&lru_pvec, 0);
> - for (page_idx = 0; page_idx < nr_pages; page_idx++) {
> - struct page *page = list_entry(pages->prev, struct page, lru);
> +#ifdef CONFIG_KEVENT_AIO
> +extern struct bio *kaio_mpage_alloc(struct block_device *bdev, sector_t first_sector,
> + int nr_vecs, gfp_t gfp_flags, void *priv);
> +extern struct bio *kaio_mpage_bio_submit(int rw, struct bio *bio);
> +#else
> +#define kaio_mpage_alloc mpage_alloc
> +#define kaio_mpage_bio_submit mpage_bio_submit
> +#endif
>
> - prefetchw(&page->flags);
> - list_del(&page->lru);
> - if (!add_to_page_cache(page, mapping,
> - page->index, GFP_KERNEL)) {
> - bio = do_mpage_readpage(bio, page,
> - nr_pages - page_idx,
> - &last_block_in_bio, &map_bh,
> - &first_logical_block,
> - get_block);
> - if (!pagevec_add(&lru_pvec, page))
> - __pagevec_lru_add(&lru_pvec);
> - } else {
> - page_cache_release(page);
> - }
> - }
> - pagevec_lru_add(&lru_pvec);
> - BUG_ON(!list_empty(pages));
> - if (bio)
> - mpage_bio_submit(READ, bio);
> - return 0;
> +int
> +mpage_readpages_aio(struct address_space *mapping, struct list_head *pages,
> + unsigned nr_pages, get_block_t get_block, void *priv)
> +{
> + return __mpage_readpages(mapping, pages, nr_pages, get_block,
> + kaio_mpage_alloc, kaio_mpage_bio_submit, priv);
> }
> -EXPORT_SYMBOL(mpage_readpages);
> +EXPORT_SYMBOL(mpage_readpages_aio);
>
> /*
> * This isn't called much at all
> @@ -433,7 +467,8 @@ int mpage_readpage(struct page *page, get_block_t get_block)
>
> clear_buffer_mapped(&map_bh);
> bio = do_mpage_readpage(bio, page, 1, &last_block_in_bio,
> - &map_bh, &first_logical_block, get_block);
> + &map_bh, &first_logical_block, get_block,
> + mpage_alloc, mpage_bio_submit, NULL);
> if (bio)
> mpage_bio_submit(READ, bio);
> return 0;
> @@ -595,7 +630,7 @@ page_is_mapped:
> alloc_new:
> if (bio == NULL) {
> bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
> - bio_get_nr_vecs(bdev), GFP_NOFS|__GFP_HIGH);
> + bio_get_nr_vecs(bdev), GFP_NOFS|__GFP_HIGH, NULL);
> if (bio == NULL)
> goto confused;
> }
> diff --git a/include/linux/mpage.h b/include/linux/mpage.h
> index cc5fb75..accdbdd 100644
> --- a/include/linux/mpage.h
> +++ b/include/linux/mpage.h
> @@ -16,6 +16,8 @@ typedef int (writepage_t)(struct page *page, struct writeback_control *wbc);
>
> int mpage_readpages(struct address_space *mapping, struct list_head *pages,
> unsigned nr_pages, get_block_t get_block);
> +int mpage_readpages_aio(struct address_space *mapping, struct list_head *pages,
> + unsigned nr_pages, get_block_t get_block, void *priv);
> int mpage_readpage(struct page *page, get_block_t get_block);
> int mpage_writepages(struct address_space *mapping,
> struct writeback_control *wbc, get_block_t get_block);
> diff --git a/kernel/kevent/kevent_aio.c b/kernel/kevent/kevent_aio.c
> new file mode 100644
> index 0000000..d4c1c5f
> --- /dev/null
> +++ b/kernel/kevent/kevent_aio.c
> @@ -0,0 +1,881 @@
> +/*
> + * 2006 Copyright (c) Evgeniy Polyakov <johnpol@....mipt.ru>
> + * All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/types.h>
> +#include <linux/spinlock.h>
> +#include <linux/list.h>
> +#include <linux/kthread.h>
> +#include <linux/slab.h>
> +#include <linux/bio.h>
> +#include <linux/pagemap.h>
> +#include <linux/file.h>
> +#include <linux/swap.h>
> +#include <linux/kevent.h>
> +
> +#define KAIO_CALL_NUM 8
> +#define KAIO_THREAD_NUM 8
> +
> +//#define KEVENT_AIO_DEBUG
> +
> +#ifdef KEVENT_AIO_DEBUG
> +#define dprintk(f, a...) printk(f, ##a)
> +#else
> +#define dprintk(f, a...) do {} while (0)
> +#endif
> +
> +struct kaio_thread
> +{
> + struct list_head req_list;
> + spinlock_t req_lock;
> + struct task_struct *thread;
> + int refcnt;
> + wait_queue_head_t wait;
> +};
> +
> +extern struct file_operations kevent_user_fops;
> +static DEFINE_PER_CPU(u32, kaio_req_counter);
> +static DEFINE_PER_CPU(int, kaio_req_cpu);
> +
> +/*
> + * Array of working threads.
> + * It can only be accessed under RCU protection,
> + * so threads reference counters are not atomic.
> + */
> +static struct kaio_thread *kaio_threads[KAIO_THREAD_NUM] __read_mostly;
> +static struct kmem_cache *kaio_req_cache __read_mostly;
> +static struct kmem_cache *kaio_priv_cache __read_mostly;
> +
> +struct kaio_req;
> +typedef int (* kaio_callback)(struct kaio_req *req, int direct);
> +
> +#define KAIO_REQ_PENDING 0
> +
> +/*
> + * Cache of kaio request callbacks.
> + * It is not allowed to change the same cache entry
> + * simultaneously (for example it is forbidden to add entries
> + * in parallel).
> + *
> + * When cache entry is scheduled for execution in one of the threads,
> + * it is forbidden to access it, since it will be freed when
> + * all callbacks have been invoked.
> + *
> + * It is possible to add callbacks into this cache from callbacks itself.
> + */
> +struct kaio_req
> +{
> + struct list_head req_entry;
> + kaio_callback call[KAIO_CALL_NUM];
> + int read_idx, add_idx;
> + int cpu;
> + long flags;
> + atomic_t refcnt;
> + void (*destructor)(struct kaio_req *);
> + void *priv;
> +};
> +
> +/*
> + * Returns pointer to thread entry for given index.
> + * Must be called under RCU protection.
> + */
> +static struct kaio_thread *kaio_get_thread(int cpu)
> +{
> + struct kaio_thread *th;
> +
> + if (cpu == -1) {
> +#if 1
> + int *cnt = &__get_cpu_var(kaio_req_cpu);
> + cpu = *cnt;
> +
> + *cnt = *cnt + 1;
> + if (*cnt >= KAIO_THREAD_NUM)
> + *cnt = 0;
> +#else
> + cpu = 0;
> +#endif
> + }
> +
> + if (unlikely(cpu >= KAIO_THREAD_NUM || !kaio_threads[cpu]))
> + return NULL;
> +
> + th = kaio_threads[cpu];
> + th->refcnt++;
> +
> + return th;
> +}
> +
> +/*
> + * Drops reference counter for given thread.
> + * Must be called under RCU protection.
> + */
> +static inline void kaio_put_thread(struct kaio_thread *th)
> +{
> + th->refcnt--;
> +}
> +
> +void kaio_schedule_req(struct kaio_req *req)
> +{
> + struct kaio_thread *th;
> + unsigned long flags;
> +
> + rcu_read_lock();
> + th = kaio_get_thread(req->cpu);
> + if (!th) {
> + req->cpu = -1;
> + th = kaio_get_thread(-1);
> + BUG_ON(!th);
> + }
> +
> + if (!test_and_set_bit(KAIO_REQ_PENDING, &req->flags)) {
> + spin_lock_irqsave(&th->req_lock, flags);
> + list_add_tail(&req->req_entry, &th->req_list);
> + spin_unlock_irqrestore(&th->req_lock, flags);
> + }
> +
> + wake_up(&th->wait);
> +
> + kaio_put_thread(th);
> + rcu_read_unlock();
> +}
> +
> +EXPORT_SYMBOL_GPL(kaio_schedule_req);
> +
> +static inline void kaio_req_get(struct kaio_req *req)
> +{
> + atomic_inc(&req->refcnt);
> +}
> +
> +static inline int kaio_req_put(struct kaio_req *req)
> +{
> + if (atomic_dec_and_test(&req->refcnt)) {
> + dprintk("%s: freeing req: %p, priv: %p.\n", __func__, req, req->priv);
> + if (req->destructor)
> + req->destructor(req);
> + kmem_cache_free(kaio_req_cache, req);
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * Append a call request into cache.
> + * Returns -EOVERFLOW in case cache is full, and 0 otherwise.
> + */
> +int kaio_append_call(struct kaio_req *req, kaio_callback call)
> +{
> + if ((req->add_idx + 1 == req->read_idx) ||
> + ((req->add_idx + 1 == KAIO_CALL_NUM) && req->read_idx == 0))
> + return -EOVERFLOW;
> +
> + req->call[req->add_idx] = call;
> +
> + dprintk("%s: req: %p, read_idx: %d, add_idx: %d, call: %p [%p].\n",
> + __func__, req, req->read_idx, req->add_idx,
> + req->call[req->read_idx], req->call[req->add_idx]);
> + if (++req->add_idx == KAIO_CALL_NUM)
> + req->add_idx = 0;
> +
> + kaio_req_get(req);
> +
> + return 0;
> +}
> +
> +EXPORT_SYMBOL_GPL(kaio_append_call);
> +
> +/*
> + * Adds one call request into given cache.
> + * If cache is NULL or full, allocate new one.
> + */
> +struct kaio_req *kaio_add_call(struct kaio_req *req, kaio_callback call, int cpu, gfp_t gflags)
> +{
> + if (req && !kaio_append_call(req, call)) {
> + kaio_schedule_req(req);
> + return req;
> + }
> +
> + req = kmem_cache_alloc(kaio_req_cache, gflags);
> + if (!req)
> + return NULL;
> +
> + memset(req->call, 0, sizeof(req->call));
> +
> + req->destructor = NULL;
> + req->cpu = cpu;
> + req->call[0] = call;
> + req->add_idx = 1;
> + req->read_idx = 0;
> + req->flags = 0;
> + atomic_set(&req->refcnt, 1);
> +
> + dprintk("%s: req: %p, call: %p [%p].\n", __func__, req, call, req->call[0]);
> +
> + return req;
> +}
> +
> +EXPORT_SYMBOL_GPL(kaio_add_call);
> +
> +/*
> + * Call appropriate callbacks in cache.
> + * This can only be called by working threads, which means that cache
> + * is filled (probably partially) and are not even accessible from
> + * the originator of requests, which means that cache will be freed
> + * when all callbacks are invoked.
> + *
> + * Callback itself can reschedule new callback into the same cache.
> + *
> + * If callback returns negative value, the whole cache will be freed.
> + * If positive value is returned, then further processing is stopped,
> + * so cache can be queued into the end of the processing FIFO by callback.
> + * If zero is returned, next callback will be invoked if any.
> + */
> +static int kaio_call(struct kaio_req *req)
> +{
> + int err = -EINVAL;
> +
> + if (likely(req->add_idx != req->read_idx)) {
> + dprintk("%s: req: %p, read_idx: %d, add_idx: %d, call: %p [%p].\n",
> + __func__, req, req->read_idx, req->add_idx,
> + req->call[req->read_idx], req->call[0]);
> + err = (*req->call[req->read_idx])(req, 0);
> + if (++req->read_idx == KAIO_CALL_NUM)
> + req->read_idx = 0;
> +
> + if (kaio_req_put(req))
> + err = 0;
> + }
> + return err;
> +}
> +
> +static int kaio_thread_process(void *data)
> +{
> + struct kaio_thread *th = data;
> + unsigned long flags;
> + struct kaio_req *req, *first;
> + DECLARE_WAITQUEUE(wait, current);
> + int err;
> +
> + add_wait_queue_exclusive(&th->wait, &wait);
> +
> + while (!kthread_should_stop()) {
> + first = req = NULL;
> + do {
> + req = NULL;
> + spin_lock_irqsave(&th->req_lock, flags);
> + if (!list_empty(&th->req_list)) {
> + req = list_entry(th->req_list.prev, struct kaio_req, req_entry);
> + if (first != req)
> + list_del(&req->req_entry);
> + }
> + spin_unlock_irqrestore(&th->req_lock, flags);
> +
> + if (!first)
> + first = req;
> + else if (first == req)
> + break;
> +
> + if (req) {
> + err = 0;
> + while ((req->read_idx != req->add_idx) && !kthread_should_stop()) {
> + dprintk("%s: req: %p, read_idx: %d, add_idx: %d, err: %d.\n",
> + __func__, req, req->read_idx, req->add_idx, err);
> + err = kaio_call(req);
> + if (err != 0)
> + break;
> + }
> +
> + if (err > 0) {
> + spin_lock_irqsave(&th->req_lock, flags);
> + list_add_tail(&req->req_entry, &th->req_list);
> + spin_unlock_irqrestore(&th->req_lock, flags);
> + }
> + }
> + } while (req);
> + __set_current_state(TASK_INTERRUPTIBLE);
> + schedule_timeout(HZ);
> + __set_current_state(TASK_RUNNING);
> + }
> +
> + remove_wait_queue(&th->wait, &wait);
> +
> + return 0;
> +}
> +
> +struct kaio_private
> +{
> + union {
> + void *sptr;
> + __u64 sdata;
> + };
> + union {
> + void *dptr;
> + __u64 ddata;
> + };
> + __u64 offset, processed;
> + __u64 count, limit;
> + struct kevent_user *kevent_user;
> +};
> +
> +extern void bio_fs_destructor(struct bio *bio);
> +
> +static void kaio_bio_destructor(struct bio *bio)
> +{
> + dprintk("%s: bio=%p, num=%u.\n", __func__, bio, bio->bi_vcnt);
> + bio_fs_destructor(bio);
> +}
> +
> +static int kaio_read_send_pages(struct kaio_req *req, int direct);
> +
> +static int kaio_mpage_end_io_read(struct bio *bio, unsigned int bytes_done, int err)
> +{
> + const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
> + struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
> + struct kaio_req *req = bio->bi_private;
> +
> + if (bio->bi_size)
> + return 1;
> +
> + do {
> + struct page *page = bvec->bv_page;
> +
> + if (--bvec >= bio->bi_io_vec)
> + prefetchw(&bvec->bv_page->flags);
> +
> + if (uptodate) {
> + SetPageUptodate(page);
> + } else {
> + ClearPageUptodate(page);
> + SetPageError(page);
> + }
> + unlock_page(page);
> + } while (bvec >= bio->bi_io_vec);
> +
> + dprintk("%s: bio: %p, req: %p, pending: %d.\n",
> + __func__, bio, req, test_bit(KAIO_REQ_PENDING, &req->flags));
> +
> + kaio_append_call(req, kaio_read_send_pages);
> + kaio_req_put(req);
> + kaio_schedule_req(req);
> +
> + bio_put(bio);
> + return 0;
> +}
> +
> +struct bio *kaio_mpage_bio_submit(int rw, struct bio *bio)
> +{
> + if (bio) {
> + bio->bi_end_io = kaio_mpage_end_io_read;
> + dprintk("%s: bio=%p, num=%u.\n", __func__, bio, bio->bi_vcnt);
> + submit_bio(READ, bio);
> + }
> + return NULL;
> +}
> +
> +struct bio *kaio_mpage_alloc(struct block_device *bdev,
> + sector_t first_sector, int nr_vecs, gfp_t gfp_flags, void *priv)
> +{
> + struct bio *bio;
> +
> + bio = bio_alloc(gfp_flags, nr_vecs);
> +
> + if (bio == NULL && (current->flags & PF_MEMALLOC)) {
> + while (!bio && (nr_vecs /= 2))
> + bio = bio_alloc(gfp_flags, nr_vecs);
> + }
> +
> + if (bio) {
> + struct kaio_req *req = priv;
> +
> + bio->bi_bdev = bdev;
> + bio->bi_sector = first_sector;
> + bio->bi_private = priv;
> + bio->bi_destructor = kaio_bio_destructor;
> + kaio_req_get(req);
> + dprintk("%s: bio: %p, req: %p, num: %d.\n", __func__, bio, priv, nr_vecs);
> + }
> + return bio;
> +}
> +
> +static ssize_t kaio_vfs_read_actor(struct kaio_private *priv, struct page *page, size_t len)
> +{
> + struct socket *sock = priv->dptr;
> + struct file *file = sock->file;
> +
> + return file->f_op->sendpage(file, page, 0, len, &file->f_pos, 1);
> +}
> +
> +static int kaio_vfs_read(struct kaio_private *priv,
> + ssize_t (*actor)(struct kaio_private *, struct page *, size_t))
> +{
> + struct address_space *mapping;
> + struct file *file = priv->sptr;
> + ssize_t actor_size;
> + loff_t isize;
> + int i = 0, pg_num;
> +
> + mapping = file->f_mapping;
> + isize = i_size_read(file->f_dentry->d_inode);
> +
> + if (priv->processed >= isize) {
> + priv->count = 0;
> + return 0;
> + }
> + priv->count = isize - priv->processed;
> + pg_num = ALIGN(min_t(u64, isize, priv->count), PAGE_SIZE) >> PAGE_SHIFT;
> +
> + dprintk("%s: start: priv: %p, ret: %d, num: %d, count: %Lu, offset: %Lu, processed: %Lu.\n",
> + __func__, priv, i, pg_num, priv->count, priv->offset, priv->processed);
> +
> + for (i=0; i<pg_num && priv->count; ++i) {
> + struct page *page;
> + size_t nr = PAGE_CACHE_SIZE;
> +
> + page = find_get_page(mapping, priv->processed >> PAGE_CACHE_SHIFT);
> + if (unlikely(page == NULL))
> + break;
> + if (!PageUptodate(page)) {
> + dprintk("%s: %2d: page=%p, processed=%Lu, count=%Lu not uptodate.\n",
> + __func__, i, page, priv->processed, priv->count);
> + page_cache_release(page);
> + break;
> + }
> +
> + if (mapping_writably_mapped(mapping))
> + flush_dcache_page(page);
> +
> + mark_page_accessed(page);
> +
> + if (nr + priv->processed > isize)
> + nr = isize - priv->processed;
> + if (nr > priv->count)
> + nr = priv->count;
> +
> + actor_size = actor(priv, page, nr);
> + if (actor_size < 0) {
> + page_cache_release(page);
> + i = (int)actor_size;
> + break;
> + }
> +
> + page_cache_release(page);
> +
> + priv->processed += actor_size;
> + priv->count -= actor_size;
> + }
> +
> + if (!priv->count)
> + i = pg_num;
> +
> + dprintk("%s: end: priv: %p, ret: %d, num: %d, count: %Lu, offset: %Lu, processed: %Lu.\n",
> + __func__, priv, i, pg_num, priv->count, priv->offset, priv->processed);
> +
> + return i;
> +}
> +
> +static int kaio_read_send_pages(struct kaio_req *req, int direct)
> +{
> + struct kaio_private *priv = req->priv;
> + struct file *file = priv->sptr;
> + struct address_space *mapping = file->f_mapping;
> + struct page *page;
> + int err, i, num;
> + u64 offset;
> + LIST_HEAD(page_pool);
> +
> + err = kaio_vfs_read(priv, &kaio_vfs_read_actor);
> + if (err < 0)
> + return err;
> +
> + if (err == 0) {
> + priv->limit >>= 1;
> + } else {
> + if (priv->limit)
> + priv->limit <<= 1;
> + else
> + priv->limit = 8;
> + }
> +
> + if (priv->offset < priv->processed)
> + priv->offset = priv->processed;
> +
> + if (!priv->count) {
> + kevent_storage_ready(&priv->kevent_user->st, NULL, KEVENT_MASK_ALL);
> + return 0;
> + }
> +
> + if (priv->offset >= priv->processed + priv->count) {
> + kaio_append_call(req, kaio_read_send_pages);
> + return 0;
> + }
> +
> + num = min_t(int, max_sane_readahead(priv->limit),
> + ALIGN(priv->count, PAGE_SIZE) >> PAGE_SHIFT);
> +
> + offset = priv->offset;
> + for (i=0; i<num; ++i) {
> + page = page_cache_alloc_cold(mapping);
> + if (!page)
> + break;
> +
> + page->index = priv->offset >> PAGE_CACHE_SHIFT;
> + list_add(&page->lru, &page_pool);
> +
> + priv->offset += PAGE_CACHE_SIZE;
> + }
> +
> + dprintk("%s: submit: req: %p, priv: %p, offset: %Lu, num: %d, limit: %Lu.\n",
> + __func__, req, priv, offset, i, priv->limit);
> +
> + err = mapping->a_ops->aio_readpages(file, mapping, &page_pool, i, req);
> + if (err) {
> + dprintk("%s: kevent_mpage_readpages failed: err=%d, count=%Lu.\n",
> + __func__, err, priv->count);
> + kaio_schedule_req(req);
> + return err;
> + }
> +
> + return 1;
> +}
> +
> +static int kaio_add_kevent(int fd, struct kaio_req *req)
> +{
> + struct ukevent uk;
> + struct file *file;
> + struct kevent_user *u;
> + int err, need_fput = 0;
> + u32 *cnt;
> +
> + file = fget_light(fd, &need_fput);
> + if (!file) {
> + err = -EBADF;
> + goto err_out;
> + }
> +
> + if (file->f_op != &kevent_user_fops) {
> + err = -EINVAL;
> + goto err_out_fput;
> + }
> +
> + u = file->private_data;
> +
> + memset(&uk, 0, sizeof(struct ukevent));
> +
> + uk.event = KEVENT_MASK_ALL;
> + uk.type = KEVENT_AIO;
> +
> + preempt_disable();
> + uk.id.raw[0] = smp_processor_id();
> + cnt = &__get_cpu_var(kaio_req_counter);
> + uk.id.raw[1] = *cnt;
> + *cnt = *cnt + 1;
> + preempt_enable();
> +
> + uk.req_flags = KEVENT_REQ_ONESHOT | KEVENT_REQ_ALWAYS_QUEUE;
> + uk.ptr = req;
> +
> + err = kevent_user_add_ukevent(&uk, u);
> + if (err)
> + goto err_out_fput;
> +
> + kevent_user_get(u);
> +
> + fput_light(file, need_fput);
> +
> + return 0;
> +
> +err_out_fput:
> + fput_light(file, need_fput);
> +err_out:
> + return err;
> +}
> +
> +static void kaio_destructor(struct kaio_req *req)
> +{
> + struct kaio_private *priv = req->priv;
> + struct socket *sock = priv->dptr;
> + struct file *file = priv->sptr;
> +
> + fput(file);
> + sockfd_put(sock);
> +
> + kevent_storage_ready(&priv->kevent_user->st, NULL, KEVENT_MASK_ALL);
> + kevent_user_put(priv->kevent_user);
> +
> + kmem_cache_free(kaio_priv_cache, req->priv);
> +}
> +
> +static struct kaio_req *kaio_sendfile(int kevent_fd, int sock_fd, struct file *file, off_t offset, size_t count)
> +{
> + struct kaio_req *req;
> + struct socket *sock;
> + struct kaio_private *priv;
> + int err;
> +
> + sock = sockfd_lookup(sock_fd, &err);
> + if (!sock)
> + goto err_out_exit;
> +
> + priv = kmem_cache_alloc(kaio_priv_cache, GFP_KERNEL);
> + if (!priv)
> + goto err_out_sput;
> +
> + priv->sptr = file;
> + priv->dptr = sock;
> + priv->offset = offset;
> + priv->count = min_t(u64, i_size_read(file->f_dentry->d_inode), count);
> + priv->processed = offset;
> + priv->limit = 128;
> +
> + req = kaio_add_call(NULL, &kaio_read_send_pages, -1, GFP_KERNEL);
> + if (!req)
> + goto err_out_free;
> +
> + req->destructor = kaio_destructor;
> + req->priv = priv;
> +
> + err = kaio_add_kevent(kevent_fd, req);
> +
> + dprintk("%s: req: %p, priv: %p, call: %p [%p], offset: %Lu, processed: %Lu, count: %Lu, err: %d.\n",
> + __func__, req, priv, &kaio_read_send_pages,
> + kaio_read_send_pages, priv->offset, priv->processed, priv->count, err);
> +
> + if (err)
> + goto err_out_remove;
> +
> + kaio_schedule_req(req);
> +
> + return req;
> +
> +err_out_remove:
> + /* It is safe to just free the object since it is guaranteed that it was not
> + * queued for processing.
> + */
> + kmem_cache_free(kaio_req_cache, req);
> +err_out_free:
> + kmem_cache_free(kaio_priv_cache, priv);
> +err_out_sput:
> + sockfd_put(sock);
> +err_out_exit:
> + return NULL;
> +
> +}
> +
> +asmlinkage long sys_aio_sendfile(int kevent_fd, int sock_fd, int in_fd, off_t offset, size_t count)
> +{
> + struct kaio_req *req;
> + struct file *file;
> + int err;
> +
> + file = fget(in_fd);
> + if (!file) {
> + err = -EBADF;
> + goto err_out_exit;
> + }
> +
> + req = kaio_sendfile(kevent_fd, sock_fd, file, offset, count);
> + if (!req) {
> + err = -EINVAL;
> + goto err_out_fput;
> + }
> +
> + return (long)req;
> +
> +err_out_fput:
> + fput(file);
> +err_out_exit:
> + return err;
> +}
> +
> +asmlinkage long sys_aio_sendfile_path(int kevent_fd, int sock_fd, char __user *filename, off_t offset, size_t count)
> +{
> + char *tmp = getname(filename);
> + int fd = PTR_ERR(tmp);
> + int flags = O_RDONLY, err;
> + struct nameidata nd;
> + struct file *file;
> + struct kaio_req *req;
> +
> + if (force_o_largefile())
> + flags = O_LARGEFILE;
> +
> + if (IS_ERR(tmp)) {
> + err = fd;
> + goto err_out_exit;
> + }
> +
> + fd = get_unused_fd();
> + if (fd < 0) {
> + err = fd;
> + goto err_out_put_name;
> + }
> +
> + if ((flags+1) & O_ACCMODE)
> + flags++;
> +
> + err = open_namei(AT_FDCWD, tmp, flags, 0400, &nd);
> + if (err)
> + goto err_out_fdput;
> +
> + file = nameidata_to_filp(&nd, flags);
> + if (!file)
> + goto err_out_fdput;
> +
> + /* One reference will be released in sys_close(),
> + * second one through req->destructor()
> + */
> + atomic_inc(&file->f_count);
> +
> + req = kaio_sendfile(kevent_fd, sock_fd, file, offset, count);
> + if (!req) {
> + err = -EINVAL;
> + goto err_out_fput;
> + }
> +
> + fd_install(fd, file);
> +
> + return fd;
> +
> +err_out_fput:
> + fput(file);
> + fput(file);
> +err_out_fdput:
> + put_unused_fd(fd);
> +err_out_put_name:
> + putname(tmp);
> +err_out_exit:
> + return err;
> +}
> +
> +static int kevent_aio_callback(struct kevent *k)
> +{
> + struct kaio_req *req = k->event.ptr;
> + struct kaio_private *priv = req->priv;
> +
> + if (!priv->count) {
> + __u32 *processed = (__u32 *)&priv->processed;
> + k->event.ret_data[0] = processed[0];
> + k->event.ret_data[1] = processed[1];
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +int kevent_aio_enqueue(struct kevent *k)
> +{
> + int err;
> + struct kaio_req *req = k->event.ptr;
> + struct kaio_private *priv = req->priv;
> +
> + err = kevent_storage_enqueue(&k->user->st, k);
> + if (err)
> + goto err_out_exit;
> +
> + priv->kevent_user = k->user;
> + if (k->event.req_flags & KEVENT_REQ_ALWAYS_QUEUE)
> + kevent_requeue(k);
> +
> + return 0;
> +
> +err_out_exit:
> + return err;
> +}
> +
> +int kevent_aio_dequeue(struct kevent *k)
> +{
> + kevent_storage_dequeue(k->st, k);
> +
> + return 0;
> +}
> +
> +static void kaio_thread_stop(struct kaio_thread *th)
> +{
> + kthread_stop(th->thread);
> + kfree(th);
> +}
> +
> +static int kaio_thread_start(struct kaio_thread **thp, int num)
> +{
> + struct kaio_thread *th;
> +
> + th = kzalloc(sizeof(struct kaio_thread), GFP_KERNEL);
> + if (!th)
> + return -ENOMEM;
> +
> + th->refcnt = 1;
> + spin_lock_init(&th->req_lock);
> + INIT_LIST_HEAD(&th->req_list);
> + init_waitqueue_head(&th->wait);
> +
> + th->thread = kthread_run(kaio_thread_process, th, "kaio/%d", num);
> + if (IS_ERR(th->thread)) {
> + int err = PTR_ERR(th->thread);
> + kfree(th);
> + return err;
> + }
> +
> + *thp = th;
> + wmb();
> +
> + return 0;
> +}
> +
> +static int __init kevent_init_aio(void)
> +{
> + struct kevent_callbacks sc = {
> + .callback = &kevent_aio_callback,
> + .enqueue = &kevent_aio_enqueue,
> + .dequeue = &kevent_aio_dequeue,
> + .flags = 0,
> + };
> + int err, i;
> +
> + kaio_req_cache = kmem_cache_create("kaio_req", sizeof(struct kaio_req),
> + 0, SLAB_PANIC, NULL, NULL);
> + kaio_priv_cache = kmem_cache_create("kaio_priv", sizeof(struct kaio_private),
> + 0, SLAB_PANIC, NULL, NULL);
> +
> + memset(kaio_threads, 0, sizeof(kaio_threads));
> +
> + for (i=0; i<KAIO_THREAD_NUM; ++i) {
> + err = kaio_thread_start(&kaio_threads[i], i);
> + if (err)
> + goto err_out_stop;
> + }
> +
> + err = kevent_add_callbacks(&sc, KEVENT_AIO);
> + if (err)
> + goto err_out_stop;
> +
> + return 0;
> +
> +err_out_stop:
> + while (--i >= 0) {
> + struct kaio_thread *th = kaio_threads[i];
> +
> + kaio_threads[i] = NULL;
> + wmb();
> +
> + kaio_thread_stop(th);
> + }
> + return err;
> +}
> +module_init(kevent_init_aio);
>
> -
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--
Suparna Bhattacharya (suparna@...ibm.com)
Linux Technology Center
IBM Software Lab, India
-
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