aboutsummaryrefslogtreecommitdiffstats
path: root/fs/direct-io.c
diff options
context:
space:
mode:
authorChristoph Lameter <clameter@sgi.com>2007-10-16 01:24:38 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 09:42:53 -0700
commitaadb4bc4a1f9108c1d0fbd121827c936c2ed4217 (patch)
tree879b7c9ba11a65958e4477c563602e08d9e6635f /fs/direct-io.c
parentfilemap: convert some unsigned long to pgoff_t (diff)
downloadlinux-dev-aadb4bc4a1f9108c1d0fbd121827c936c2ed4217.tar.xz
linux-dev-aadb4bc4a1f9108c1d0fbd121827c936c2ed4217.zip
SLUB: direct pass through of page size or higher kmalloc requests
This gets rid of all kmalloc caches larger than page size. A kmalloc request larger than PAGE_SIZE > 2 is going to be passed through to the page allocator. This works both inline where we will call __get_free_pages instead of kmem_cache_alloc and in __kmalloc. kfree is modified to check if the object is in a slab page. If not then the page is freed via the page allocator instead. Roughly similar to what SLOB does. Advantages: - Reduces memory overhead for kmalloc array - Large kmalloc operations are faster since they do not need to pass through the slab allocator to get to the page allocator. - Performance increase of 10%-20% on alloc and 50% on free for PAGE_SIZEd allocations. SLUB must call page allocator for each alloc anyways since the higher order pages which that allowed avoiding the page alloc calls are not available in a reliable way anymore. So we are basically removing useless slab allocator overhead. - Large kmallocs yields page aligned object which is what SLAB did. Bad things like using page sized kmalloc allocations to stand in for page allocate allocs can be transparently handled and are not distinguishable from page allocator uses. - Checking for too large objects can be removed since it is done by the page allocator. Drawbacks: - No accounting for large kmalloc slab allocations anymore - No debugging of large kmalloc slab allocations. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/direct-io.c')
0 files changed, 0 insertions, 0 deletions