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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Subject: Re: [patch -mm 11/18] oom: avoid oom killer for lowmem allocations
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Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton <akpm@linux-foundation.org>, Rik van Riel <riel@redhat.com>, Nick Piggin <npiggin@suse.de>, Oleg Nesterov <oleg@redhat.com>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Balbir Singh <balbir@linux.vnet.ibm.com>, linux-mm@kvack.org
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> Previously, the heuristic provided some protection for those tasks with
> CAP_SYS_RAWIO, but this is no longer necessary since we will not be
> killing tasks for the purposes of ISA allocations.

Seems incorrect. CAP_SYS_RAWIO tasks usually both use GFP_KERNEL and GFP_DMA.
Even if last allocation is GFP_KERNEL, it doesn't provide any gurantee the
process doesn't have any in flight I/O.

Then, we can't remove for RAWIO protection from oom heuristics. but the code
itself seems ok though.



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