diff options
author | Mark Fasheh <mfasheh@suse.com> | 2010-04-06 03:17:15 +0200 |
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committer | Joel Becker <joel.becker@oracle.com> | 2010-05-06 03:18:07 +0200 |
commit | b07f8f24dfe54da0f074b78949044842e8df881f (patch) | |
tree | 8cc24b0a1e02a9b7f1241fbfecca50ac6881b938 /fs/ocfs2/reservations.c | |
parent | ocfs2: increase the default size of local alloc windows (diff) | |
download | linux-b07f8f24dfe54da0f074b78949044842e8df881f.tar.xz linux-b07f8f24dfe54da0f074b78949044842e8df881f.zip |
ocfs2: change default reservation window sizes
The default reservation size of 4 (32-bit windows) is a bit too ambitious.
Scale it back to 16 bits (resv_level=2). I have been testing various sizes
on a 4-node cluster which runs a mixed workload that is heavily threaded.
With a 256MB local alloc, I get *roughly* the following levels of average file
fragmentation:
resv_level=0 70%
resv_level=1 21%
resv_level=2 23%
resv_level=3 24%
resv_level=4 60%
resv_level=5 did not test
resv_level=6 60%
resv_level=2 seemed like a good compromise between not letting windows be
too small, but not so big that heavier workloads will immediately suffer
without tuning.
This patch also change the behavior of directory reservations - they now
track file reservations. The previous compromise of giving directory
windows only 8 bits wound up fragmenting more at some window sizes because
file allocations had smaller unused windows to poach from.
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Diffstat (limited to 'fs/ocfs2/reservations.c')
-rw-r--r-- | fs/ocfs2/reservations.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/fs/ocfs2/reservations.c b/fs/ocfs2/reservations.c index 7fc6cfee95f1..87fa35791f18 100644 --- a/fs/ocfs2/reservations.c +++ b/fs/ocfs2/reservations.c @@ -55,9 +55,10 @@ static unsigned int ocfs2_resv_window_bits(struct ocfs2_reservation_map *resmap, if (!(resv->r_flags & OCFS2_RESV_FLAG_DIR)) { /* 8, 16, 32, 64, 128, 256, 512, 1024 */ bits = 4 << osb->osb_resv_level; - } else - bits = OCFS2_RESV_DIR_WINDOW_BITS; - + } else { + /* For now, treat directories the same as files. */ + bits = 4 << osb->osb_resv_level; + } return bits; } |