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| author | Eric Sandeen <sandeen@redhat.com> | 2010-07-27 17:56:06 +0200 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2010-07-27 17:56:06 +0200 |
| commit | 506bf2d82165c09b179a5077e01037f6270a4db3 (patch) | |
| tree | 9e0a92d5da86f8f402032a408148cb8676ade715 /fs/ext4/mballoc.c | |
| parent | ext4: move aio completion after unwritten extent conversion (diff) | |
| download | linux-506bf2d82165c09b179a5077e01037f6270a4db3.tar.xz linux-506bf2d82165c09b179a5077e01037f6270a4db3.zip | |
ext4: allocate stripe-multiple IOs on stripe boundaries
For some reason, today mballoc only allocates IOs which are exactly
stripe-sized on a stripe boundary. If you have a multiple (say, a
128k IO on a 64k stripe) you may end up unaligned.
It seems to me that a simple change to align stripe-multiple IOs
on stripe boundaries would be a very good idea, unless this breaks
some other mballoc heuristic for some reason...
Reported-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/mballoc.c')
| -rw-r--r-- | fs/ext4/mballoc.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 5338b1ca64bb..a75de7d44dc9 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1822,8 +1822,7 @@ void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac, /* * This is a special case for storages like raid5 - * we try to find stripe-aligned chunks for stripe-size requests - * XXX should do so at least for multiples of stripe size as well + * we try to find stripe-aligned chunks for stripe-size-multiple requests */ static noinline_for_stack void ext4_mb_scan_aligned(struct ext4_allocation_context *ac, @@ -2092,8 +2091,8 @@ repeat: ac->ac_groups_scanned++; if (cr == 0) ext4_mb_simple_scan_group(ac, &e4b); - else if (cr == 1 && - ac->ac_g_ex.fe_len == sbi->s_stripe) + else if (cr == 1 && sbi->s_stripe && + !(ac->ac_g_ex.fe_len % sbi->s_stripe)) ext4_mb_scan_aligned(ac, &e4b); else ext4_mb_complex_scan_group(ac, &e4b); |