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authorMark Fasheh <mfasheh@suse.com>2008-07-28 18:02:53 -0700
committerMark Fasheh <mfasheh@suse.com>2008-10-13 13:57:57 -0700
commit9c7af40b210e87f8fddd97b0badc0a352862234a (patch)
treedeb248e5295439b96ad9bd1789e8512f93803142 /mm/allocpercpu.c
parentebcee4b5c9136096f64ee6f691a013d7c0a4bc34 (diff)
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ocfs2: throttle back local alloc when low on disk space
Ocfs2's local allocator disables itself for the duration of a mount point when it has trouble allocating a large enough area from the primary bitmap. That can cause performance problems, especially for disks which were only temporarily full or fragmented. This patch allows for the allocator to shrink it's window first, before being disabled. Later, it can also be re-enabled so that any performance drop is minimized. To do this, we allow the value of osb->local_alloc_bits to be shrunk when needed. The default value is recorded in a mostly read-only variable so that we can re-initialize when required. Locking had to be updated so that we could protect changes to local_alloc_bits. Mostly this involves protecting various local alloc values with the osb spinlock. A new state is also added, OCFS2_LA_THROTTLED, which is used when the local allocator is has shrunk, but is not disabled. If the available space dips below 1 megabyte, the local alloc file is disabled. In either case, local alloc is re-enabled 30 seconds after the event, or when an appropriate amount of bits is seen in the primary bitmap. Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Diffstat (limited to 'mm/allocpercpu.c')
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