kernel.git/mm/slab.c, branch linux-3.12.y

mm/slab: fix unexpected index mapping result of kmalloc_size(INDEX_NODE+1)

2015-10-28T15:38:09Z

commit 03a2d2a3eafe4015412cf4e9675ca0e2d9204074 upstream. Commit description is copied from the original post of this bug: http://comments.gmane.org/gmane.linux.kernel.mm/135349 Kernels after v3.9 use kmalloc_size(INDEX_NODE + 1) to get the next larger cache size than the size index INDEX_NODE mapping. In kernels 3.9 and earlier we used malloc_sizes[INDEX_L3 + 1].cs_size. However, sometimes we can't get the right output we expected via kmalloc_size(INDEX_NODE + 1), causing a BUG(). The mapping table in the latest kernel is like: index = {0, 1, 2 , 3, 4, 5, 6, n} size = {0, 96, 192, 8, 16, 32, 64, 2^n} The mapping table before 3.10 is like this: index = {0 , 1 , 2, 3, 4 , 5 , 6, n} size = {32, 64, 96, 128, 192, 256, 512, 2^(n+3)} The problem on my mips64 machine is as follows: (1) When configured DEBUG_SLAB && DEBUG_PAGEALLOC && DEBUG_LOCK_ALLOC && DEBUG_SPINLOCK, the sizeof(struct kmem_cache_node) will be "150", and the macro INDEX_NODE turns out to be "2": #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node)) (2) Then the result of kmalloc_size(INDEX_NODE + 1) is 8. (3) Then "if(size >= kmalloc_size(INDEX_NODE + 1)" will lead to "size = PAGE_SIZE". (4) Then "if ((size >= (PAGE_SIZE >> 3))" test will be satisfied and "flags |= CFLGS_OFF_SLAB" will be covered. (5) if (flags & CFLGS_OFF_SLAB)" test will be satisfied and will go to "cachep->slabp_cache = kmalloc_slab(slab_size, 0u)", and the result here may be NULL while kernel bootup. (6) Finally,"BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache));" causes the BUG info as the following shows (may be only mips64 has this problem): This patch fixes the problem of kmalloc_size(INDEX_NODE + 1) and removes the BUG by adding 'size >= 256' check to guarantee that all necessary small sized slabs are initialized regardless sequence of slab size in mapping table. Fixes: e33660165c90 ("slab: Use common kmalloc_index/kmalloc_size...") Signed-off-by: Joonsoo Kim Reported-by: Liuhailong Acked-by: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Jiri Slaby

mm, slab: initialize object alignment on cache creation

2014-10-13T13:41:31Z

commit d4a5fca592b9ab52b90bb261a90af3c8f53be011 upstream. Since commit 4590685546a3 ("mm/sl[aou]b: Common alignment code"), the "ralign" automatic variable in __kmem_cache_create() may be used as uninitialized. The proper alignment defaults to BYTES_PER_WORD and can be overridden by SLAB_RED_ZONE or the alignment specified by the caller. This fixes https://bugzilla.kernel.org/show_bug.cgi?id=85031 Signed-off-by: David Rientjes Reported-by: Andrei Elovikov Acked-by: Christoph Lameter Cc: Pekka Enberg Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Jiri Slaby

mm: optimize put_mems_allowed() usage

2014-09-26T09:51:56Z

commit d26914d11751b23ca2e8747725f2cae10c2f2c1b upstream. Since put_mems_allowed() is strictly optional, its a seqcount retry, we don't need to evaluate the function if the allocation was in fact successful, saving a smp_rmb some loads and comparisons on some relative fast-paths. Since the naming, get/put_mems_allowed() does suggest a mandatory pairing, rename the interface, as suggested by Mel, to resemble the seqcount interface. This gives us: read_mems_allowed_begin() and read_mems_allowed_retry(), where it is important to note that the return value of the latter call is inverted from its previous incarnation. Signed-off-by: Peter Zijlstra Signed-off-by: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Mel Gorman Signed-off-by: Jiri Slaby

slab: correct pfmemalloc check

2014-09-26T09:51:50Z

commit 73293c2f900d0adbb6a415b312cd57976d5ae242 upstream. We checked pfmemalloc by slab unit, not page unit. You can see this in is_slab_pfmemalloc(). So other pages don't need to be set/cleared pfmemalloc. And, therefore we should check pfmemalloc in page flag of first page, but current implementation don't do that. virt_to_head_page(obj) just return 'struct page' of that object, not one of first page, since the SLAB don't use __GFP_COMP when CONFIG_MMU. To get 'struct page' of first page, we first get a slab and try to get it via virt_to_head_page(slab->s_mem). Acked-by: Andi Kleen Signed-off-by: Joonsoo Kim Signed-off-by: Pekka Enberg Signed-off-by: Mel Gorman Signed-off-by: Jiri Slaby

kernel: delete __cpuinit usage from all core kernel files

2013-07-14T23:36:59Z

The __cpuinit type of throwaway sections might have made sense some time ago when RAM was more constrained, but now the savings do not offset the cost and complications. For example, the fix in commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time") is a good example of the nasty type of bugs that can be created with improper use of the various __init prefixes. After a discussion on LKML[1] it was decided that cpuinit should go the way of devinit and be phased out. Once all the users are gone, we can then finally remove the macros themselves from linux/init.h. This removes all the uses of the __cpuinit macros from C files in the core kernel directories (kernel, init, lib, mm, and include) that don't really have a specific maintainer. [1] https://lkml.org/lkml/2013/5/20/589 Signed-off-by: Paul Gortmaker

Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux

2013-07-14T22:14:29Z

Pull slab update from Pekka Enberg: "Highlights: - Fix for boot-time problems on some architectures due to init_lock_keys() not respecting kmalloc_caches boundaries (Christoph Lameter) - CONFIG_SLUB_CPU_PARTIAL requested by RT folks (Joonsoo Kim) - Fix for excessive slab freelist draining (Wanpeng Li) - SLUB and SLOB cleanups and fixes (various people)" I ended up editing the branch, and this avoids two commits at the end that were immediately reverted, and I instead just applied the oneliner fix in between myself. * 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux slub: Check for page NULL before doing the node_match check mm/slab: Give s_next and s_stop slab-specific names slob: Check for NULL pointer before calling ctor() slub: Make cpu partial slab support configurable slab: add kmalloc() to kernel API documentation slab: fix init_lock_keys slob: use DIV_ROUND_UP where possible slub: do not put a slab to cpu partial list when cpu_partial is 0 mm/slub: Use node_nr_slabs and node_nr_objs in get_slabinfo mm/slub: Drop unnecessary nr_partials mm/slab: Fix /proc/slabinfo unwriteable for slab mm/slab: Sharing s_next and s_stop between slab and slub mm/slab: Fix drain freelist excessively slob: Rework #ifdeffery in slab.h mm, slab: moved kmem_cache_alloc_node comment to correct place

mm/slab: Give s_next and s_stop slab-specific names

2013-07-08T08:02:17Z

Give s_next and s_stop slab-specific names instead of exporting "s_next" and "s_stop". Signed-off-by: Wanpeng Li Signed-off-by: Pekka Enberg

slab: fix init_lock_keys

2013-07-07T15:58:31Z

Some architectures (e.g. powerpc built with CONFIG_PPC_256K_PAGES=y CONFIG_FORCE_MAX_ZONEORDER=11) get PAGE_SHIFT + MAX_ORDER > 26. In 3.10 kernels, CONFIG_LOCKDEP=y with PAGE_SHIFT + MAX_ORDER > 26 makes init_lock_keys() dereference beyond kmalloc_caches[26]. This leads to an unbootable system (kernel panic at initializing SLAB) if one of kmalloc_caches[26...PAGE_SHIFT+MAX_ORDER-1] is not NULL. Fix this by making sure that init_lock_keys() does not dereference beyond kmalloc_caches[26] arrays. Signed-off-by: Christoph Lameter Reported-by: Tetsuo Handa Cc: Pekka Enberg Cc: [3.10.x] Signed-off-by: Andrew Morton Signed-off-by: Pekka Enberg

mm/slab: Sharing s_next and s_stop between slab and slub

2013-07-07T15:37:47Z

This patch shares s_next and s_stop between slab and slub. Acked-by: Christoph Lameter Signed-off-by: Wanpeng Li Signed-off-by: Pekka Enberg

mm/slab: Fix drain freelist excessively

2013-07-07T15:37:46Z

The drain_freelist is called to drain slabs_free lists for cache reap, cache shrink, memory hotplug callback etc. The tofree parameter should be the number of slab to free instead of the number of slab objects to free. This patch fix the callers that pass # of objects. Make sure they pass # of slabs. Acked-by: Christoph Lameter Signed-off-by: Wanpeng Li Signed-off-by: Pekka Enberg