Messages in this thread |  | | | Date | Tue, 3 Nov 2009 08:02:28 +0900 (JST) | | Subject | Re: [RFC][-mm][PATCH 1/6] oom-killer: updates for classification of OOM | | From | "KAMEZAWA Hiroyuki" <> |
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Thanks! your review is very helpful around NUMA.
Christoph Lameter wrote: > On Mon, 2 Nov 2009, KAMEZAWA Hiroyuki wrote: > >> /* >> - * Types of limitations to the nodes from which allocations may occur >> + * Types of limitations to zones from which allocations may occur >> */ > > "Types of limitations that may cause OOMs"? MEMCG limitations are not zone > based. > ah, will rewrite.
>> */ >> >> -unsigned long badness(struct task_struct *p, unsigned long uptime) >> +static unsigned long __badness(struct task_struct *p, >> + unsigned long uptime, enum oom_constraint constraint, >> + struct mem_cgroup *mem) >> { >> unsigned long points, cpu_time, run_time; >> struct mm_struct *mm; > > Why rename this function? You are adding a global_badness anyways. > just because of history of my own updates...i.e. mistake. no reason. sorry.
> >> + /* >> + * In numa environ, almost all allocation will be against NORMAL zone. > > The typical allocations will be against the policy_zone! SGI IA64 (and > others) have policy_zone == GFP_DMA. > Hmm ? ok. I thought GPF_DMA for ia64 was below 4G zone. If all memory are GFP_DMA(as ppc), that means no lowemem. I'll just rewrite above comments as "typical allocation will be against policy_zone".
>> + * But some small area, ex)GFP_DMA for ia64 or GFP_DMA32 for x86-64 >> + * can cause OOM. We can use policy_zone for checking lowmem. >> + */ > > Simply say that we are checking if the zone constraint is below the policy > zone? > ok, will rewrite. Too verbose just bacause policy_zone isn't well unknown.
>> + * Now, only mempolicy specifies nodemask. But if nodemask >> + * covers all nodes, this oom is global oom. >> + */ >> + if (nodemask && !nodes_equal(node_states[N_HIGH_MEMORY], *nodemask)) >> + ret = CONSTRAINT_MEMORY_POLICY; > > Huh? A cpuset can also restrict the nodes? > cpuset doesn't pass nodemask for allocation(now). It checks its nodemask in get_free_page_from_freelist(), internally.
>> + /* >> + * If not __GFP_THISNODE, zonelist containes all nodes. And if > > Dont see any __GFP_THISNODE checks here. > If __GFP_THISNODE, zonelist includes local node only. Then zonelist/nodemask check will hunt it and result will be CONSTRAINT_MEMPOLICY. Then...hum....recommending CONSTRAINT_THISNODE ? >> panic("out of memory from page fault. panic_on_oom is selected.\n"); >> >> read_lock(&tasklist_lock); >> - __out_of_memory(0, 0); /* unknown gfp_mask and order */ >> + /* >> + * Considering nature of pages required for page-fault,this must be >> + * global OOM (if not cpuset...). Then, CONSTRAINT_NONE is correct. >> + * zonelist, nodemasks are unknown... >> + */ >> + __out_of_memory(0, CONSTRAINT_NONE, 0, NULL); >> read_unlock(&tasklist_lock); > > Page faults can occur on processes that have memory restrictions. > yes. comments are bad. will rewrite. But we don't have any useful information here.Fixing pagefault_out_of_memory is on my to-do-list. It seems wrong.
But a condition unclear to me is when VM_FAULT_OOM can be returned without oom-kill...so plz give me time.
Thanks, -Kame
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