Messages in this thread Patch in this message | | | Date | Sat, 24 Sep 2005 01:04:14 +0530 | From | Alok Kataria <> | Subject | Re: 2.6.14-rc1-git-now still dying in mm/slab - this time line 1849 |
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On Wed, 2005-09-21 at 06:33, Christoph Lameter wrote:
Hi Christoph, I have some doubts over this...
>/On Tue, 20 Sep 2005, Petr Vandrovec wrote: > >> slab belonging to node#1, while having acquired lock for cachep belonging >> to node #0. Due to this check_spinlock_acquired_node(cachep, nodeid) fails >> (check_spinlock_acquired_node(cachep, 0) would succeed). > >Hmmm. If a node runs out of memory then pages from another node may end up >on the slab list of a node. But it seems that free_block cannot handle >that properly. > >How are you producing the problem? > >Could you try the following patch: > >--- > >The numa slab allocator may allocate pages from foreign nodes onto the lists >for a particular node if a node runs out of memory. Inspecting the slab->nodeid >field will not reflect that the page is now in use for the slabs of another node. >/ > / /
IMO the slab->nodeid field just lets us know to which nodes list3 is this slab attached, irrespective of the node from which node the memory was got.
>/This patch fixes that issue by adding a node field to free_block so that the caller >can indicate which node currently uses a slab. > >/ > But the nodeid is already accessible through the slab-descriptor of this object, and this nodeid is set in the cache_grow function.
>/Also removes the check for the current node from kmalloc_cache_node since the >process may shift later to another node which may lead to an allocation on another >node than intended. >/ > Yeah that is possible, but won't putting a check in __cache_alloc_node after disabling the interrupt be better, because kmalloc_node/kmem_cache_alloc_node can be called at runtime as well, and getting the object directly from the slabs, instead of the arraycaches may slow up things. Thus tweaking the patch a little.
Thanks & Regards, Alok
Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Index: linux-2.6.13/mm/slab.c =================================================================== --- linux-2.6.13.orig/mm/slab.c 2005-09-24 00:08:00.221900000 +0530 +++ linux-2.6.13/mm/slab.c 2005-09-24 00:24:12.206645250 +0530 @@ -2507,16 +2507,12 @@ #define cache_alloc_debugcheck_after(a,b,objp,d) (objp) #endif - -static inline void *__cache_alloc(kmem_cache_t *cachep, unsigned int __nocast flags) +static inline void *____cache_alloc(kmem_cache_t *cachep, unsigned int __nocast flags) { - unsigned long save_flags; void* objp; struct array_cache *ac; - cache_alloc_debugcheck_before(cachep, flags); - - local_irq_save(save_flags); + check_irq_off(); ac = ac_data(cachep); if (likely(ac->avail)) { STATS_INC_ALLOCHIT(cachep); @@ -2526,6 +2522,18 @@ STATS_INC_ALLOCMISS(cachep); objp = cache_alloc_refill(cachep, flags); } + return objp; +} + +static inline void *__cache_alloc(kmem_cache_t *cachep, unsigned int __nocast flags) +{ + unsigned long save_flags; + void* objp; + + cache_alloc_debugcheck_before(cachep, flags); + + local_irq_save(save_flags); + objp = ____cache_alloc(cachep, flags); local_irq_restore(save_flags); objp = cache_alloc_debugcheck_after(cachep, flags, objp, __builtin_return_address(0)); return objp; @@ -2841,7 +2849,7 @@ unsigned long save_flags; void *ptr; - if (nodeid == numa_node_id() || nodeid == -1) + if (nodeid == -1) return __cache_alloc(cachep, flags); if (unlikely(!cachep->nodelists[nodeid])) { @@ -2852,6 +2860,8 @@ cache_alloc_debugcheck_before(cachep, flags); local_irq_save(save_flags); + if (nodeid == numa_node_id()) + ____cache_alloc(cachep, flags); ptr = __cache_alloc_node(cachep, flags, nodeid); local_irq_restore(save_flags); ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, __builtin_return_address(0)); | |