The patch titled SLUB: avoid checking for a valid object before zeroing on the fast path has been removed from the -mm tree. Its filename was slub-avoid-checking-for-a-valid-object-before-zeroing-on-the-fast-path.patch This patch was dropped because it is obsolete The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: SLUB: avoid checking for a valid object before zeroing on the fast path From: Christoph Lameter <clameter@xxxxxxx> The fast path always results in a valid object. Move the check for the NULL pointer to the slow branch that calls __slab_alloc. Only __slab_alloc can return NULL if there is no memory available anymore and that case is exceedingly rare. Signed-off-by: Christoph Lameter <clameter@xxxxxxx> Reviewed-by: Pekka Enberg <penberg@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/slub.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff -puN mm/slub.c~slub-avoid-checking-for-a-valid-object-before-zeroing-on-the-fast-path mm/slub.c --- a/mm/slub.c~slub-avoid-checking-for-a-valid-object-before-zeroing-on-the-fast-path +++ a/mm/slub.c @@ -1553,19 +1553,22 @@ static __always_inline void *slab_alloc( local_irq_save(flags); c = get_cpu_slab(s, smp_processor_id()); - if (unlikely(!c->freelist || !node_match(c, node))) + if (unlikely(!c->freelist || !node_match(c, node))) { object = __slab_alloc(s, gfpflags, node, addr, c); - - else { + if (unlikely(!object)) { + local_irq_restore(flags); + goto out; + } + } else { object = c->freelist; c->freelist = object[c->offset]; } local_irq_restore(flags); - if (unlikely((gfpflags & __GFP_ZERO) && object)) + if (unlikely((gfpflags & __GFP_ZERO))) memset(object, 0, c->objsize); - +out: return object; } _ Patches currently in -mm which might be from clameter@xxxxxxx are origin.patch pagecache-zeroing-zero_user_segment-zero_user_segments-and-zero_user.patch move-vmalloc_to_page-to-mm-vmalloc.patch vmalloc-add-const-to-void-parameters.patch i386-resolve-dependency-of-asm-i386-pgtableh-on-highmemh.patch is_vmalloc_addr-check-if-an-address-is-within-the-vmalloc-boundaries.patch vmalloc-clean-up-page-array-indexing.patch vunmap-return-page-array-passed-on-vmap.patch slub-avoid-checking-for-a-valid-object-before-zeroing-on-the-fast-path.patch slub-__slab_alloc-exit-path-consolidation.patch slub-provide-unique-end-marker-for-each-slab.patch slub-avoid-referencing-kmem_cache-structure-in-__slab_alloc.patch slub-optional-fast-path-using-cmpxchg_local.patch slub-do-our-own-locking-via-slab_lock-and-slab_unlock.patch slub-restructure-slab-alloc.patch slub-comment-kmem_cache_cpu-structure.patch slub-fix-sysfs-refcounting.patch vm-allow-get_page_unless_zero-on-compound-pages.patch bufferhead-revert-constructor-removal.patch swapin_readahead-excise-numa-bogosity.patch page-allocator-clean-up-pcp-draining-functions.patch vmstat-small-revisions-to-refresh_cpu_vm_stats.patch page-allocator-get-rid-of-the-list-of-cold-pages.patch vmstat-remove-prefetch.patch set_page_refcounted-vm_bug_on-fix.patch page-migraton-handle-orphaned-pages.patch mm-fix-section-mismatch-warning-in-sparsec.patch gregkh-driver-kset-move-sys-slab-to-sys-kernel-slab-slabinfo-fallback-from-sys-kernel-slab-to-sys-slab.patch git-unionfs.patch git-newsetup.patch percpu-__percpu_alloc_mask-can-dynamically-size-percpu_data.patch memcontrol-move-oom-task-exclusion-to-tasklist.patch oom-add-sysctl-to-enable-task-memory-dump.patch add-cmpxchg_local-to-asm-generic-for-per-cpu-atomic-operations.patch add-cmpxchg_local-cmpxchg64-and-cmpxchg64_local-to-ia64.patch dentries-extract-common-code-to-remove-dentry-from-lru.patch dentries-extract-common-code-to-remove-dentry-from-lru-fix.patch modules-handle-symbols-that-have-a-zero-value.patch modules-include-sectionsh-to-avoid-defining-linker-variables.patch reiser4.patch reiser4-portion-of-zero_user-cleanup-patch.patch page-owner-tracking-leak-detector.patch - To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html