On Thu, Apr 24, 2003 at 10:22:22AM +0530, Suparna Bhattacharya wrote:
> Here is a revised version of the filesystem AIO patches
> for 2.5.68.
>
> 02aiord.patch : Filesystem aio read
Changes to generic_file_aio_read code to use the aio
retry infrastructure. The main blocking points addressed
are lock_page and wait_on_page_locked.
Regards
Suparna
-- Suparna Bhattacharya (suparna@in.ibm.com) Linux Technology Center IBM Software Labs, India02aiord.patch ............. include/linux/pagemap.h | 19 ++++++++++++++ mm/filemap.c | 63 ++++++++++++++++++++++++++++++++++++++++-------- 2 files changed, 72 insertions(+), 10 deletions(-)
diff -ur -X /home/kiran/dontdiff linux-2.5.68/include/linux/pagemap.h linux-aio-2568/include/linux/pagemap.h --- linux-2.5.68/include/linux/pagemap.h Mon Apr 21 23:30:40 2003 +++ linux-aio-2568/include/linux/pagemap.h Mon Apr 21 17:26:58 2003 @@ -135,6 +135,16 @@ if (TestSetPageLocked(page)) __lock_page(page); } + +extern int FASTCALL(__lock_page_wq(struct page *page, wait_queue_t *wait)); +static inline int lock_page_wq(struct page *page, wait_queue_t *wait) +{ + if (TestSetPageLocked(page)) + return __lock_page_wq(page, wait); + else + return 0; +} + /* * This is exported only for wait_on_page_locked/wait_on_page_writeback. @@ -155,6 +165,15 @@ wait_on_page_bit(page, PG_locked); } +extern int FASTCALL(wait_on_page_bit_wq(struct page *page, int bit_nr, + wait_queue_t *wait)); +static inline int wait_on_page_locked_wq(struct page *page, wait_queue_t *wait) +{ + if (PageLocked(page)) + return wait_on_page_bit_wq(page, PG_locked, wait); + return 0; +} + /* * Wait for a page to complete writeback */ diff -ur -X /home/kiran/dontdiff linux-2.5.68/mm/filemap.c linux-aio-2568/mm/filemap.c --- linux-2.5.68/mm/filemap.c Mon Apr 21 23:30:40 2003 +++ linux-aio-2568/mm/filemap.c Tue Apr 22 00:28:55 2003 @@ -268,19 +268,32 @@ return &zone->wait_table[hash_ptr(page, zone->wait_table_bits)]; } -void wait_on_page_bit(struct page *page, int bit_nr) +int wait_on_page_bit_wq(struct page *page, int bit_nr, wait_queue_t *wait) { wait_queue_head_t *waitqueue = page_waitqueue(page); - DEFINE_WAIT(wait); + DEFINE_WAIT(local_wait); + if (!wait) + wait = &local_wait; + do { - prepare_to_wait(waitqueue, &wait, TASK_UNINTERRUPTIBLE); + prepare_to_wait(waitqueue, wait, TASK_UNINTERRUPTIBLE); if (test_bit(bit_nr, &page->flags)) { sync_page(page); + if (!is_sync_wait(wait)) + return -EIOCBRETRY; io_schedule(); } } while (test_bit(bit_nr, &page->flags)); - finish_wait(waitqueue, &wait); + finish_wait(waitqueue, wait); + + return 0; +} +EXPORT_SYMBOL(wait_on_page_bit_wq); + +void wait_on_page_bit(struct page *page, int bit_nr) +{ + wait_on_page_bit_wq(page, bit_nr, NULL); } EXPORT_SYMBOL(wait_on_page_bit); @@ -336,19 +349,31 @@ * chances are that on the second loop, the block layer's plug list is empty, * so sync_page() will then return in state TASK_UNINTERRUPTIBLE. */ -void __lock_page(struct page *page) +int __lock_page_wq(struct page *page, wait_queue_t *wait) { wait_queue_head_t *wqh = page_waitqueue(page); - DEFINE_WAIT(wait); + DEFINE_WAIT(local_wait); + if (!wait) + wait = &local_wait; + while (TestSetPageLocked(page)) { - prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); + prepare_to_wait(wqh, wait, TASK_UNINTERRUPTIBLE); if (PageLocked(page)) { sync_page(page); + if (!is_sync_wait(wait)) + return -EIOCBRETRY; io_schedule(); } } - finish_wait(wqh, &wait); + finish_wait(wqh, wait); + return 0; +} +EXPORT_SYMBOL(__lock_page_wq); + +void __lock_page(struct page *page) +{ + __lock_page_wq(page, NULL); } EXPORT_SYMBOL(__lock_page); @@ -621,7 +655,13 @@ goto page_ok; /* Get exclusive access to the page ... */ - lock_page(page); + + if (lock_page_wq(page, current->io_wait)) { + pr_debug("queued lock page \n"); + error = -EIOCBRETRY; + /* TBD: should we hold on to the cached page ? */ + goto sync_error; + } /* Did it get unhashed before we got the lock? */ if (!page->mapping) { @@ -643,12 +683,19 @@ if (!error) { if (PageUptodate(page)) goto page_ok; - wait_on_page_locked(page); + if (wait_on_page_locked_wq(page, current->io_wait)) { + pr_debug("queued wait_on_page \n"); + error = -EIOCBRETRY; + /*TBD:should we hold on to the cached page ?*/ + goto sync_error; + } + if (PageUptodate(page)) goto page_ok; error = -EIO; } +sync_error: /* UHHUH! A synchronous read error occurred. Report it */ desc->error = error; page_cache_release(page); @@ -819,6 +866,10 @@ struct kiocb kiocb; ssize_t ret; + if (current->io_wait != NULL) { + printk("current->io_wait != NULL\n"); + dump_stack(); + } init_sync_kiocb(&kiocb, filp); ret = __generic_file_aio_read(&kiocb, &local_iov, 1, ppos); if (-EIOCBQUEUED == ret) @@ -851,6 +902,7 @@ { read_descriptor_t desc; + BUG_ON(current->io_wait != NULL); if (!count) return 0; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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