From: Hisashi Hifumi <hifumi.hisa...@oss.ntt.co.jp>
A page can have multiple buffers and even if a page is not uptodate, some
buffers
can be uptodate on pagesize != blocksize environment.
This aops checks that all buffers which correspond to a part of a file
that we want to read are uptodate. If so, we do not have to issue actual
read IO to HDD even if a page is not uptodate because the portion we
want to read are uptodate.
"block_is_partially_uptodate" function is already used by ext2/3/4.
With the following patch random read/write mixed workloads or random read after
random write workloads can be optimized and we can get performance improvement.
Signed-off-by: Hisashi Hifumi <hifumi.hisa...@oss.ntt.co.jp>
Signed-off-by: Mark Fasheh <mfas...@suse.com>
---
fs/ocfs2/aops.c | 23 ++++++++++++-----------
1 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 8e1709a..b2c52b3 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -1956,15 +1956,16 @@ static int ocfs2_write_end(struct file *file, struct
address_space *mapping,
}
const struct address_space_operations ocfs2_aops = {
- .readpage = ocfs2_readpage,
- .readpages = ocfs2_readpages,
- .writepage = ocfs2_writepage,
- .write_begin = ocfs2_write_begin,
- .write_end = ocfs2_write_end,
- .bmap = ocfs2_bmap,
- .sync_page = block_sync_page,
- .direct_IO = ocfs2_direct_IO,
- .invalidatepage = ocfs2_invalidatepage,
- .releasepage = ocfs2_releasepage,
- .migratepage = buffer_migrate_page,
+ .readpage = ocfs2_readpage,
+ .readpages = ocfs2_readpages,
+ .writepage = ocfs2_writepage,
+ .write_begin = ocfs2_write_begin,
+ .write_end = ocfs2_write_end,
+ .bmap = ocfs2_bmap,
+ .sync_page = block_sync_page,
+ .direct_IO = ocfs2_direct_IO,
+ .invalidatepage = ocfs2_invalidatepage,
+ .releasepage = ocfs2_releasepage,
+ .migratepage = buffer_migrate_page,
+ .is_partially_uptodate = block_is_partially_uptodate,
};
--
1.5.6
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