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authorMark Fasheh <mfasheh@suse.com>2010-04-06 05:17:15 +0400
committerJoel Becker <joel.becker@oracle.com>2010-05-06 05:18:07 +0400
commitb07f8f24dfe54da0f074b78949044842e8df881f (patch)
tree8cc24b0a1e02a9b7f1241fbfecca50ac6881b938
parent6b82021b9e91cd689fdffadbcdb9a42597bbe764 (diff)
downloadlinux-b07f8f24dfe54da0f074b78949044842e8df881f.tar.xz
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>
-rw-r--r--Documentation/filesystems/ocfs2.txt2
-rw-r--r--fs/ocfs2/reservations.c7
-rw-r--r--fs/ocfs2/reservations.h2
3 files changed, 6 insertions, 5 deletions
diff --git a/Documentation/filesystems/ocfs2.txt b/Documentation/filesystems/ocfs2.txt
index 412df9095937..32339e584a9a 100644
--- a/Documentation/filesystems/ocfs2.txt
+++ b/Documentation/filesystems/ocfs2.txt
@@ -80,6 +80,6 @@ user_xattr (*) Enables Extended User Attributes.
nouser_xattr Disables Extended User Attributes.
acl Enables POSIX Access Control Lists support.
noacl (*) Disables POSIX Access Control Lists support.
-resv_level=4 (*) Set how agressive allocation reservations will be.
+resv_level=2 (*) Set how agressive allocation reservations will be.
Valid values are between 0 (reservations off) to 8
(maximum space for reservations).
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;
}
diff --git a/fs/ocfs2/reservations.h b/fs/ocfs2/reservations.h
index 34bb308375c5..022aff601e15 100644
--- a/fs/ocfs2/reservations.h
+++ b/fs/ocfs2/reservations.h
@@ -22,7 +22,7 @@
#include <linux/rbtree.h>
-#define OCFS2_DEFAULT_RESV_LEVEL 4
+#define OCFS2_DEFAULT_RESV_LEVEL 2
#define OCFS2_MAX_RESV_LEVEL 9
#define OCFS2_MIN_RESV_LEVEL 0