diff options
| author | Ezequiel Garcia | 2012-10-19 09:33:10 -0300 |
|---|---|---|
| committer | Pekka Enberg | 2012-10-31 08:50:43 +0200 |
| commit | 999d8795d438d396936811b185428d70b7b7de6d (patch) | |
| tree | b63098f47faa341ec81cb9f07a47b986898d09d9 /mm/slob.c | |
| parent | 1b4f59e356cc94929305bd107b7f38eec62715ad (diff) | |
mm/slob: Drop usage of page->private for storing page-sized allocations
This field was being used to store size allocation so it could be
retrieved by ksize(). However, it is a bad practice to not mark a page
as a slab page and then use fields for special purposes.
There is no need to store the allocated size and
ksize() can simply return PAGE_SIZE << compound_order(page).
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Diffstat (limited to 'mm/slob.c')
| -rw-r--r-- | mm/slob.c | 24 |
1 files changed, 10 insertions, 14 deletions
diff --git a/mm/slob.c b/mm/slob.c index a08e4681fd0d..06a5ec70e728 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -28,9 +28,8 @@ * from kmalloc are prepended with a 4-byte header with the kmalloc size. * If kmalloc is asked for objects of PAGE_SIZE or larger, it calls * alloc_pages() directly, allocating compound pages so the page order - * does not have to be separately tracked, and also stores the exact - * allocation size in page->private so that it can be used to accurately - * provide ksize(). These objects are detected in kfree() because slob_page() + * does not have to be separately tracked. + * These objects are detected in kfree() because PageSlab() * is false for them. * * SLAB is emulated on top of SLOB by simply calling constructors and @@ -455,11 +454,6 @@ __do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller) if (likely(order)) gfp |= __GFP_COMP; ret = slob_new_pages(gfp, order, node); - if (ret) { - struct page *page; - page = virt_to_page(ret); - page->private = size; - } trace_kmalloc_node(caller, ret, size, PAGE_SIZE << order, gfp, node); @@ -514,18 +508,20 @@ EXPORT_SYMBOL(kfree); size_t ksize(const void *block) { struct page *sp; + int align; + unsigned int *m; BUG_ON(!block); if (unlikely(block == ZERO_SIZE_PTR)) return 0; sp = virt_to_page(block); - if (PageSlab(sp)) { - int align = max(ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN); - unsigned int *m = (unsigned int *)(block - align); - return SLOB_UNITS(*m) * SLOB_UNIT; - } else - return sp->private; + if (unlikely(!PageSlab(sp))) + return PAGE_SIZE << compound_order(sp); + + align = max(ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN); + m = (unsigned int *)(block - align); + return SLOB_UNITS(*m) * SLOB_UNIT; } EXPORT_SYMBOL(ksize); |