kernel.git/mm/slab_common.c, branch linux-3.18.y

mm/slab: fix unalignment problem on Malta with EVA due to slab merge

2014-11-14T00:17:05Z

Unlike SLUB, sometimes, object isn't started at the beginning of the slab in SLAB. This causes the unalignment problem after slab merging is supported by commit 12220dea07f1 ("mm/slab: support slab merge"). Following is the report from Markos that fail to boot on Malta with EVA. Calibrating delay loop... 19.86 BogoMIPS (lpj=99328) pid_max: default: 32768 minimum: 301 Mount-cache hash table entries: 4096 (order: 0, 16384 bytes) Mountpoint-cache hash table entries: 4096 (order: 0, 16384 bytes) Kernel bug detected[#1]: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.17.0-05639-g12220dea07f1 #1631 task: 1f04f5d8 ti: 1f050000 task.ti: 1f050000 epc : 80141190 alloc_unbound_pwq+0x234/0x304 Not tainted ra : 80141184 alloc_unbound_pwq+0x228/0x304 Process swapper/0 (pid: 1, threadinfo=1f050000, task=1f04f5d8, tls=00000000) Call Trace: alloc_unbound_pwq+0x234/0x304 apply_workqueue_attrs+0x11c/0x294 __alloc_workqueue_key+0x23c/0x470 init_workqueues+0x320/0x400 do_one_initcall+0xe8/0x23c kernel_init_freeable+0x9c/0x224 kernel_init+0x10/0x100 ret_from_kernel_thread+0x14/0x1c [ end trace cb88537fdc8fa200 ] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b alloc_unbound_pwq() allocates slab object from pool_workqueue. This kmem_cache requires 256 bytes alignment, but, current merging code doesn't honor that, and merge it with kmalloc-256. kmalloc-256 requires only cacheline size alignment so that above failure occurs. However, in x86, kmalloc-256 is luckily aligned in 256 bytes, so the problem didn't happen on it. To fix this problem, this patch introduces alignment mismatch check in find_mergeable(). This will fix the problem. Signed-off-by: Joonsoo Kim Reported-by: Markos Chandras Tested-by: Markos Chandras Acked-by: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/slab_common: don't check for duplicate cache names

2014-10-29T23:33:15Z

The SLUB cache merges caches with the same size and alignment and there was long standing bug with this behavior: - create the cache named "foo" - create the cache named "bar" (which is merged with "foo") - delete the cache named "foo" (but it stays allocated because "bar" uses it) - create the cache named "foo" again - it fails because the name "foo" is already used That bug was fixed in commit 694617474e33 ("slab_common: fix the check for duplicate slab names") by not warning on duplicate cache names when the SLUB subsystem is used. Recently, cache merging was implemented the with SLAB subsystem too, in 12220dea07f1 ("mm/slab: support slab merge")). Therefore we need stop checking for duplicate names even for the SLAB subsystem. This patch fixes the bug by removing the check. Signed-off-by: Mikulas Patocka Acked-by: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memcg: move memcg_update_cache_size() to slab_common.c

2014-10-10T02:25:59Z

`While growing per memcg caches arrays, we jump between memcontrol.c and slab_common.c in a weird way: memcg_alloc_cache_id - memcontrol.c memcg_update_all_caches - slab_common.c memcg_update_cache_size - memcontrol.c There's absolutely no reason why memcg_update_cache_size can't live on the slab's side though. So let's move it there and settle it comfortably amid per-memcg cache allocation functions. Besides, this patch cleans this function up a bit, removing all the useless comments from it, and renames it to memcg_update_cache_params to conform to memcg_alloc/free_cache_params, which we already have in slab_common.c. Signed-off-by: Vladimir Davydov Acked-by: Johannes Weiner Acked-by: Michal Hocko Cc: Christoph Lameter Cc: Glauber Costa Cc: Joonsoo Kim Cc: David Rientjes Cc: Pekka Enberg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memcg: move memcg_{alloc,free}_cache_params to slab_common.c

2014-10-10T02:25:59Z

The only reason why they live in memcontrol.c is that we get/put css reference to the owner memory cgroup in them. However, we can do that in memcg_{un,}register_cache. OTOH, there are several reasons to move them to slab_common.c. First, I think that the less public interface functions we have in memcontrol.h the better. Since the functions I move don't depend on memcontrol, I think it's worth making them private to slab, especially taking into account that the arrays are defined on the slab's side too. Second, the way how per-memcg arrays are updated looks rather awkward: it proceeds from memcontrol.c (__memcg_activate_kmem) to slab_common.c (memcg_update_all_caches) and back to memcontrol.c again (memcg_update_array_size). In the following patches I move the function relocating the arrays (memcg_update_array_size) to slab_common.c and therefore get rid this circular call path. I think we should have the cache allocation stuff in the same place where we have relocation, because it's easier to follow the code then. So I move arrays alloc/free functions to slab_common.c too. The third point isn't obvious. I'm going to make the list_lru structure per-memcg to allow targeted kmem reclaim. That means we will have per-memcg arrays in list_lrus too. It turns out that it's much easier to update these arrays in list_lru.c rather than in memcontrol.c, because all the stuff we need is defined there. This patch makes memcg caches arrays allocation path conform that of the upcoming list_lru. So let's move these functions to slab_common.c and make them static. Signed-off-by: Vladimir Davydov Acked-by: Johannes Weiner Acked-by: Michal Hocko Cc: Christoph Lameter Cc: Glauber Costa Cc: Joonsoo Kim Cc: David Rientjes Cc: Pekka Enberg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/slab_common: commonize slab merge logic

2014-10-10T02:25:51Z

Slab merge is good feature to reduce fragmentation. Now, it is only applied to SLUB, but, it would be good to apply it to SLAB. This patch is preparation step to apply slab merge to SLAB by commonizing slab merge logic. Signed-off-by: Joonsoo Kim Cc: Randy Dunlap Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/slab_common: move kmem_cache definition to internal header

2014-10-10T02:25:50Z

We don't need to keep kmem_cache definition in include/linux/slab.h if we don't need to inline kmem_cache_size(). According to my code inspection, this function is only called at lc_create() in lib/lru_cache.c which may be called at initialization phase of something, so we don't need to inline it. Therfore, move it to slab_common.c and move kmem_cache definition to internal header. After this change, we can change kmem_cache definition easily without full kernel build. For instance, we can turn on/off CONFIG_SLUB_STATS without full kernel build. [akpm@linux-foundation.org: export kmem_cache_size() to modules] [rdunlap@infradead.org: add header files to fix kmemcheck.c build errors] Signed-off-by: Joonsoo Kim Acked-by: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Zhang Yanfei Signed-off-by: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/slab_common.c: suppress warning

2014-10-10T02:25:50Z

False positive: mm/slab_common.c: In function 'kmem_cache_create': mm/slab_common.c:204: warning: 's' may be used uninitialized in this function Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: move slab related stuff from util.c to slab_common.c

2014-08-07T01:01:15Z

Functions krealloc(), __krealloc(), kzfree() belongs to slab API, so should be placed in slab_common.c Also move slab allocator's tracepoints defenitions to slab_common.c No functional changes here. Signed-off-by: Andrey Ryabinin Acked-by: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux into for-3.16-rcX

2014-07-22T22:38:27Z

slab: delete cache from list after __kmem_cache_shutdown succeeds

2014-06-04T23:54:08Z

Currently, on kmem_cache_destroy we delete the cache from the slab_list before __kmem_cache_shutdown, inserting it back to the list on failure. Initially, this was done, because we could release the slab_mutex in __kmem_cache_shutdown to delete sysfs slub entry, but since commit 41a212859a4d ("slub: use sysfs'es release mechanism for kmem_cache") we remove sysfs entry later in kmem_cache_destroy after dropping the slab_mutex, so that no implementation of __kmem_cache_shutdown can ever release the lock. Therefore we can simplify the code a bit by moving list_del after __kmem_cache_shutdown. Signed-off-by: Vladimir Davydov Cc: Christoph Lameter Cc: Pekka Enberg Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds