From a60e78e57a17d55bbd5a96da16fe9649d364b987 Mon Sep 17 00:00:00 2001
From: Subhash Peddamallu <subhash.peddamallu@gmail.com>
Date: Mon, 16 Feb 2009 10:27:07 +0100
Subject: fs/bio: bio_alloc_bioset: pass right object ptr to mempool_free

When freeing from bio pool use right ptr to account for bs->front_pad,
instead of bio ptr,

Signed-off-by: Subhash Peddamallu <subhash.peddamallu@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
 fs/bio.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'fs')

diff --git a/fs/bio.c b/fs/bio.c
index 062299acbcc..72ab251cdb9 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -302,9 +302,10 @@ void bio_init(struct bio *bio)
 struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
 {
 	struct bio *bio = NULL;
+	void *p;
 
 	if (bs) {
-		void *p = mempool_alloc(bs->bio_pool, gfp_mask);
+		p = mempool_alloc(bs->bio_pool, gfp_mask);
 
 		if (p)
 			bio = p + bs->front_pad;
@@ -329,7 +330,7 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
 			}
 			if (unlikely(!bvl)) {
 				if (bs)
-					mempool_free(bio, bs->bio_pool);
+					mempool_free(p, bs->bio_pool);
 				else
 					kfree(bio);
 				bio = NULL;
-- 
cgit v1.2.3


From 78f707bfc723552e8309b7c38a8d0cc51012e813 Mon Sep 17 00:00:00 2001
From: Jens Axboe <jens.axboe@oracle.com>
Date: Tue, 17 Feb 2009 13:59:08 +0100
Subject: block: revert part of 18ce3751ccd488c78d3827e9f6bf54e6322676fb

The above commit added WRITE_SYNC and switched various places to using
that for committing writes that will be waited upon immediately after
submission. However, this causes a performance regression with AS and CFQ
for ext3 at least, since sync_dirty_buffer() will submit some writes with
WRITE_SYNC while ext3 has sumitted others dependent writes without the sync
flag set. This causes excessive anticipation/idling in the IO scheduler
because sync and async writes get interleaved, causing a big performance
regression for the below test case (which is meant to simulate sqlite
like behaviour).

---- test case ----

int main(int argc, char **argv)
{

	int fdes, i;
	FILE *fp;
	struct timeval start;
	struct timeval end;
	struct timeval res;

	gettimeofday(&start, NULL);
	for (i=0; i<ROWS; i++) {
		fp = fopen("test_file", "a");
		fprintf(fp, "Some Text Data\n");
		fdes = fileno(fp);
		fsync(fdes);
		fclose(fp);
	}
	gettimeofday(&end, NULL);

	timersub(&end, &start, &res);
	fprintf(stdout, "time to write %d lines is %ld(msec)\n", ROWS,
			(res.tv_sec*1000000 + res.tv_usec)/1000);

	return 0;
}

-------------------

Thanks to Sean.White@APCC.com for tracking down this performance
regression and providing a test case.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
 fs/buffer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'fs')

diff --git a/fs/buffer.c b/fs/buffer.c
index 665d446b25b..62b57e330b6 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3108,7 +3108,7 @@ int sync_dirty_buffer(struct buffer_head *bh)
 	if (test_clear_buffer_dirty(bh)) {
 		get_bh(bh);
 		bh->b_end_io = end_buffer_write_sync;
-		ret = submit_bh(WRITE_SYNC, bh);
+		ret = submit_bh(WRITE, bh);
 		wait_on_buffer(bh);
 		if (buffer_eopnotsupp(bh)) {
 			clear_buffer_eopnotsupp(bh);
-- 
cgit v1.2.3