The patch titled
Subject: direct-io: fix boundary block handling
has been removed from the -mm tree. Its filename was
direct-io-fix-boundary-block-handling.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Jan Kara <jack@xxxxxxx>
Subject: direct-io: fix boundary block handling
When we read/write a file sequentially, we will read/write not only the
data blocks but also the indirect blocks that may not be physically
adjacent to the data blocks. So filesystems set the BH_Boundary flag to
submit the previous I/O before reading/writing an indirect block.
However the generic direct IO code mishandles buffer_boundary(), setting
sdio->boundary before each submit_page_section() call which results in
sending only one page bios as underlying code thinks this page is the last
in the contiguous extent. So fix the problem by setting sdio->boundary
only if the current page is really the last one in the mapped extent.
With this patch and "direct-io: submit bio after boundary buffer is added
to it" I've measured about 10% throughput improvement of direct IO reads
on ext3 with SATA harddrive (from 90 MB/s to 100 MB/s). With ramdisk, the
improvement was about 3-fold (from 350 MB/s to 1.2 GB/s). For other
filesystems (such as ext4), the improvements won't be as visible because
the frequency of BH_Boundary flag being set is much smaller.
Signed-off-by: Jan Kara <jack@xxxxxxx>
Reported-by: Kazuya Mio <k-mio@xxxxxxxxxxxxx>
Tested-by: Kazuya Mio <k-mio@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/direct-io.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff -puN fs/direct-io.c~direct-io-fix-boundary-block-handling fs/direct-io.c
--- a/fs/direct-io.c~direct-io-fix-boundary-block-handling
+++ a/fs/direct-io.c
@@ -969,7 +969,8 @@ do_holes:
this_chunk_bytes = this_chunk_blocks << blkbits;
BUG_ON(this_chunk_bytes == 0);
- sdio->boundary = buffer_boundary(map_bh);
+ if (this_chunk_blocks == sdio->blocks_available)
+ sdio->boundary = buffer_boundary(map_bh);
ret = submit_page_section(dio, sdio, page,
offset_in_page,
this_chunk_bytes,
_
Patches currently in -mm which might be from jack@xxxxxxx are
origin.patch
linux-next.patch
kthread-implement-probe_kthread_data.patch
workqueue-include-workqueue-info-when-printing-debug-dump-of-a-worker-task.patch
writeback-set-worker-desc-to-identify-writeback-workers-in-task-dumps.patch
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