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path: root/fs/ocfs2/localalloc.h
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2010-05-05ocfs2: increase the default size of local alloc windowsMark Fasheh
I have observed that the current size of 8M gives us pretty poor fragmentation on multi-threaded workloads which do lots of writes. Generally, I can increase the size of local alloc windows and observe a marked decrease in fragmentation, even up and beyond window sizes of 512 megabytes. This makes sense for a couple reasons - larger local alloc means more room for reservation windows. On multi-node workloads the larger local alloc helps as well because we don't have to do window slides as often. Also, I removed the OCFS2_DEFAULT_LOCAL_ALLOC_SIZE constant as it is no longer used and the comment above it was out of date. To test fragmentation, I used a workload which launched 4 threads that did 4k writes into a series of about 140 alternating files. With resv_level=2, and a 4k/4k file system I observed the following average fragmentation for various localalloc= parameters: localalloc= avg. fragmentation 8 48 32 16 64 10 120 7 On larger cluster sizes, the difference is more dramatic. The new default size top out at 256M, which we'll only get for cluster sizes of 32K and above. Signed-off-by: Mark Fasheh <mfasheh@suse.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2010-05-05ocfs2: clean up localalloc mount option size parsingMark Fasheh
This patch pulls the local alloc sizing code into localalloc.c and provides a callout to it from ocfs2_fill_super(). Behavior is essentially unchanged except that I correctly calculate the maximum local alloc size. The old code in ocfs2_parse_options() calculated the max size as: ocfs2_local_alloc_size(sb) * 8 which is correct, in bits. Unfortunately though the option passed in is in megabytes. Ultimately, this bug made no real difference - the shrink code would catch a too-large size and bring it down to something reasonable. Still, it's less than efficient as-is. Signed-off-by: Mark Fasheh <mfasheh@suse.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
2008-10-13ocfs2: throttle back local alloc when low on disk spaceMark Fasheh
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>
2007-09-20ocfs2: Allow smaller allocations during large writesMark Fasheh
The ocfs2 write code loops through a page much like the block code, except that ocfs2 allocation units can be any size, including larger than page size. Typically it's equal to or larger than page size - most kernels run 4k pages, the minimum ocfs2 allocation (cluster) size. Some changes introduced during 2.6.23 changed the way writes to pages are handled, and inadvertantly broke support for > 4k page size. Instead of just writing one cluster at a time, we now handle the whole page in one pass. This means that multiple (small) seperate allocations might happen in the same pass. The allocation code howver typically optimizes by getting the maximum which was reserved. This triggered a BUG_ON in the extend code where it'd ask for a single bit (for one part of a > 4k page) and get back more than it asked for. Fix this by providing a variant of the high level allocation function which allows the caller to specify a maximum. The traditional function remains and just calls the new one with a maximum determined from the initial reservation. Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-12-01ocfs2: Remove struct ocfs2_journal_handle in favor of handle_tMark Fasheh
This is mostly a search and replace as ocfs2_journal_handle is now no more than a container for a handle_t pointer. ocfs2_commit_trans() becomes very straight forward, and we remove some out of date comments / code. Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-12-01ocfs2: don't use handle for locking in allocation functionsMark Fasheh
Instead we record our state on the allocation context structure which all callers already know about and lifetime correctly. This means the reservation functions don't need a handle passed in any more, and we can also take it off the alloc context. Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-01-03[PATCH] OCFS2: The Second Oracle Cluster FilesystemMark Fasheh
The OCFS2 file system module. Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com> Signed-off-by: Kurt Hackel <kurt.hackel@oracle.com>