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authorKen Chen <kenneth.w.chen@intel.com>2005-05-01 08:59:16 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-05-01 08:59:16 -0700
commit954d3e95369cf73b4bc1e570729f68264a0e6fe0 (patch)
tree542c6435428848f02a0eb060a83b3dd1a7f90083 /fs/aio.c
parent644d3a088a3b862ed0b57c286cf58a6bd338ce08 (diff)
downloadlinux-stericsson-954d3e95369cf73b4bc1e570729f68264a0e6fe0.tar.gz
[PATCH] aio: optimize io_submit_one()
This patch optimizes io_submit_one to call aio_run_iocb() directly if ctx->run_list is empty. When the list is empty, the operation of adding to the list, then call to __aio_run_iocbs() is unnecessary because these operations are done in one atomic step. ctx->run_list always has only one element in this case. This optimization speeds up industry standard db transaction processing benchmark by 0.2%. Signed-off-by: Ken Chen <kenneth.w.chen@intel.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Suparna Bhattacharya <suparna@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/aio.c')
-rw-r--r--fs/aio.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 674bb47fed29..7afa222f6802 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1514,10 +1514,14 @@ int fastcall io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
goto out_put_req;
spin_lock_irq(&ctx->ctx_lock);
- list_add_tail(&req->ki_run_list, &ctx->run_list);
- /* drain the run list */
- while (__aio_run_iocbs(ctx))
- ;
+ if (likely(list_empty(&ctx->run_list))) {
+ aio_run_iocb(req);
+ } else {
+ list_add_tail(&req->ki_run_list, &ctx->run_list);
+ /* drain the run list */
+ while (__aio_run_iocbs(ctx))
+ ;
+ }
spin_unlock_irq(&ctx->ctx_lock);
aio_put_req(req); /* drop extra ref to req */
return 0;