Messages in this thread Patch in this message | | | Date | Wed, 4 Nov 2009 17:09:44 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | [BUGFIX][PATCH] oom-kill: fix NUMA consraint check with nodemask |
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If clarification is not enough, let me know. Thank you for all your review in RFC version. Thanks, -Kame == From: KAMEZAWA Hiroyuki <kamezawa.hioryu@jp.fujitsu.com>
Fixing node-oriented allocation handling in oom-kill.c I myself think this as bugfix not as enhancement.
In these days, things are changed as - alloc_pages() eats nodemask as its arguments, __alloc_pages_nodemask(). - mempolicy don't maintain its own private zonelists. (And cpuset doesn't use nodemask for __alloc_pages_nodemask())
So, current oom-killer's check function is wrong.
This patch does - check nodemask, if nodemask && nodemask != node_states[N_HIGH_MEMORY] this is never be CONSTRAINT_NONE. We assume this from mempolicy. - Scan all zonelist under nodemask, if it hits cpuset's wall this faiulre is from cpuset. And - modifies the caller of out_of_memory not to call oom if __GFP_THISNODE. This doesn't change "current" behavior. If callers use __GFP_THISNODE, it should handle "page allocation failure" by itself.
Changelog: 2009/11/04 - cut out as bug-fix for passing nodemask. - added GFP_THISNODE sanity check.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hioryu@jp.fujitsu.com> --- drivers/char/sysrq.c | 2 +- mm/oom_kill.c | 38 ++++++++++++++++++++++++++------------ mm/page_alloc.c | 10 ++++++++-- 3 files changed, 35 insertions(+), 15 deletions(-)
Index: mmotm-2.6.32-Nov2/drivers/char/sysrq.c =================================================================== --- mmotm-2.6.32-Nov2.orig/drivers/char/sysrq.c +++ mmotm-2.6.32-Nov2/drivers/char/sysrq.c @@ -339,7 +339,7 @@ static struct sysrq_key_op sysrq_term_op static void moom_callback(struct work_struct *ignored) { - out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0); + out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0, NULL); } static DECLARE_WORK(moom_work, moom_callback); Index: mmotm-2.6.32-Nov2/mm/oom_kill.c =================================================================== --- mmotm-2.6.32-Nov2.orig/mm/oom_kill.c +++ mmotm-2.6.32-Nov2/mm/oom_kill.c @@ -196,27 +196,40 @@ unsigned long badness(struct task_struct /* * Determine the type of allocation constraint. */ +#ifdef CONFIG_NUMA static inline enum oom_constraint constrained_alloc(struct zonelist *zonelist, - gfp_t gfp_mask) + gfp_t gfp_mask, nodemask_t *nodemask) { -#ifdef CONFIG_NUMA struct zone *zone; struct zoneref *z; enum zone_type high_zoneidx = gfp_zone(gfp_mask); - nodemask_t nodes = node_states[N_HIGH_MEMORY]; + int ret = CONSTRAINT_NONE; - for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) - if (cpuset_zone_allowed_softwall(zone, gfp_mask)) - node_clear(zone_to_nid(zone), nodes); - else + /* + * The nodemask here is a nodemask passed to alloc_pages(). Now, + * cpuset doesn't use this nodemask for its hardwall/softwall/hierarchy + * feature. Then, only mempolicy use this nodemask. + */ + if (nodemask && nodes_equal(*nodemask, node_states[N_HIGH_MEMORY])) + ret = CONSTRAINT_MEMORY_POLICY; + + /* Check this allocation failure is caused by cpuset's wall function */ + for_each_zone_zonelist_nodemask(zone, z, zonelist, + high_zoneidx, nodemask) + if (!cpuset_zone_allowed_softwall(zone, gfp_mask)) return CONSTRAINT_CPUSET; - if (!nodes_empty(nodes)) - return CONSTRAINT_MEMORY_POLICY; -#endif + /* __GFP_THISNODE never calls OOM.*/ + return ret; +} +#else +static inline enum oom_constraint constrained_alloc(struct zonelist *zonelist, + gfp_t gfp_mask, nodemask_t *nodemask) +{ return CONSTRAINT_NONE; } +#endif /* * Simple selection loop. We chose the process with the highest @@ -603,7 +616,8 @@ rest_and_return: * OR try to be smart about which process to kill. Note that we * don't have to be perfect here, we just have to be good. */ -void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order) +void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, + int order, nodemask_t *nodemask) { unsigned long freed = 0; enum oom_constraint constraint; @@ -622,7 +636,7 @@ void out_of_memory(struct zonelist *zone * Check if there were limitations on the allocation (only relevant for * NUMA) that may require different handling. */ - constraint = constrained_alloc(zonelist, gfp_mask); + constraint = constrained_alloc(zonelist, gfp_mask, nodemask); read_lock(&tasklist_lock); switch (constraint) { Index: mmotm-2.6.32-Nov2/mm/page_alloc.c =================================================================== --- mmotm-2.6.32-Nov2.orig/mm/page_alloc.c +++ mmotm-2.6.32-Nov2/mm/page_alloc.c @@ -1667,9 +1667,15 @@ __alloc_pages_may_oom(gfp_t gfp_mask, un /* The OOM killer will not help higher order allocs */ if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_NOFAIL)) goto out; - + /* + * In usual, GFP_THISNODE contains __GFP_NORETRY and we never hit this. + * Sanity check for bare calls of __GFP_THISNODE, not real OOM. + * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER. + */ + if (gfp_mask & __GFP_THISNODE) + goto out; /* Exhausted what can be done so it's blamo time */ - out_of_memory(zonelist, gfp_mask, order); + out_of_memory(zonelist, gfp_mask, order, nodemask); out: clear_zonelist_oom(zonelist, gfp_mask);
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