Messages in this thread | | | Date | Wed, 11 Nov 2009 12:04:15 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [BUGFIX][PATCH] oom-kill: fix NUMA consraint check with nodemask v3 |
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On Tue, 10 Nov 2009 18:49:51 -0800 (PST) David Rientjes <rientjes@google.com> wrote:
> On Wed, 11 Nov 2009, KAMEZAWA Hiroyuki wrote: > > > Index: mm-test-kernel/drivers/char/sysrq.c > > =================================================================== > > --- mm-test-kernel.orig/drivers/char/sysrq.c > > +++ mm-test-kernel/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: mm-test-kernel/mm/oom_kill.c > > =================================================================== > > --- mm-test-kernel.orig/mm/oom_kill.c > > +++ mm-test-kernel/mm/oom_kill.c > > @@ -196,27 +196,45 @@ 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) > > We should probably remove the inline specifier, there's only one caller > currently and if additional ones were added in the future this function > should probably not be replicated. > Hmm, ok, remove.
> > { > > -#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. mempolicy is an only user of nodemask here. > > + */ > > + if (nodemask) { > > + nodemask_t mask; > > + /* check mempolicy's nodemask contains all N_HIGH_MEMORY */ > > + nodes_and(mask, *nodemask, node_states[N_HIGH_MEMORY]); > > + if (!nodes_equal(mask, node_states[N_HIGH_MEMORY])) > > + return CONSTRAINT_MEMORY_POLICY; > > + } > > Although a nodemask_t was previously allocated on the stack, we should > probably change this to use NODEMASK_ALLOC() for kernels with higher > CONFIG_NODES_SHIFT since allocations can happen very deep into the stack. > > There should be a way around that, however. Shouldn't > > if (nodes_subset(node_states[N_HIGH_MEMORY], *nodemask)) > return CONSTRAINT_MEMORY_POLICY; > > be sufficient? >
Ah, I didn't notice nodes_subset(). Thank you, I'll use it.
> > + > > + /* 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 CONSTRAINT_NONE; > > } > > +#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 +621,8 @@ 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; > > @@ -622,11 +641,12 @@ 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) { > > case CONSTRAINT_MEMORY_POLICY: > > + /* kill by process's its own memory alloc limitation */ > > I don't understand this comment. > remove this. But it seems not to be well known that current is always killed if CONSTRAINT_MEMPOLICY.
> > oom_kill_process(current, gfp_mask, order, 0, NULL, > > "No available memory (MPOL_BIND)"); > > break; > > Index: mm-test-kernel/mm/page_alloc.c > > =================================================================== > > --- mm-test-kernel.orig/mm/page_alloc.c > > +++ mm-test-kernel/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); > > This doesn't seem like the right place for this check; should we even try > direct reclaim for bare users of __GFP_THISNODE? No, hugepage has to do reclaim.
> If we're adding it for sanity even though no callers would currently hit it, > it also is a potential escape route for __GFP_NOFAIL.
will add __GFP_NOFAIL check.
Thanks, -Kame
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