Commit 229615de authored by Hisashi Hifumi's avatar Hisashi Hifumi Committed by Steven Whitehouse

GFS2: Pagecache usage optimization on GFS2

I introduced "is_partially_uptodate" aops for GFS2.

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.

I did a performance test using the sysbench.

#sysbench --num-threads=16 --max-requests=200000 --test=fileio --file-num=1
--file-block-size=8K --file-total-size=2G --file-test-mode=rndrw --file-fsync-freq=0
--file-rw-ratio=1 run

-2.6.29-rc6
Test execution summary:
    total time:                          202.6389s
    total number of events:              200000
    total time taken by event execution: 2580.0480
    per-request statistics:
         min:                            0.0000s
         avg:                            0.0129s
         max:                            49.5852s
         approx.  95 percentile:         0.0462s

-2.6.29-rc6-patched
Test execution summary:
    total time:                          177.8639s
    total number of events:              200000
    total time taken by event execution: 2419.0199
    per-request statistics:
         min:                            0.0000s
         avg:                            0.0121s
         max:                            52.4306s
         approx.  95 percentile:         0.0444s

arch: ia64
pagesize: 16k
blocksize: 4k
Signed-off-by: default avatarHisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent 02ab1721
...@@ -1096,6 +1096,7 @@ static const struct address_space_operations gfs2_writeback_aops = { ...@@ -1096,6 +1096,7 @@ static const struct address_space_operations gfs2_writeback_aops = {
.releasepage = gfs2_releasepage, .releasepage = gfs2_releasepage,
.direct_IO = gfs2_direct_IO, .direct_IO = gfs2_direct_IO,
.migratepage = buffer_migrate_page, .migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
}; };
static const struct address_space_operations gfs2_ordered_aops = { static const struct address_space_operations gfs2_ordered_aops = {
...@@ -1111,6 +1112,7 @@ static const struct address_space_operations gfs2_ordered_aops = { ...@@ -1111,6 +1112,7 @@ static const struct address_space_operations gfs2_ordered_aops = {
.releasepage = gfs2_releasepage, .releasepage = gfs2_releasepage,
.direct_IO = gfs2_direct_IO, .direct_IO = gfs2_direct_IO,
.migratepage = buffer_migrate_page, .migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
}; };
static const struct address_space_operations gfs2_jdata_aops = { static const struct address_space_operations gfs2_jdata_aops = {
...@@ -1125,6 +1127,7 @@ static const struct address_space_operations gfs2_jdata_aops = { ...@@ -1125,6 +1127,7 @@ static const struct address_space_operations gfs2_jdata_aops = {
.bmap = gfs2_bmap, .bmap = gfs2_bmap,
.invalidatepage = gfs2_invalidatepage, .invalidatepage = gfs2_invalidatepage,
.releasepage = gfs2_releasepage, .releasepage = gfs2_releasepage,
.is_partially_uptodate = block_is_partially_uptodate,
}; };
void gfs2_set_aops(struct inode *inode) void gfs2_set_aops(struct inode *inode)
......
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