Groups > linux.kernel > #1207537

Re: [PATCH] mm: make page pfmemalloc check more robust

From	Vlastimil Babka <vbabka@suse.cz>
Newsgroups	linux.kernel
Subject	Re: [PATCH] mm: make page pfmemalloc check more robust
Date	2015-08-14 15:30 +0200
Message-ID	<pXndw-3ix-9@gated-at.bofh.it> (permalink)
References	<pWWGm-7c5-29@gated-at.bofh.it> <pWWQ2-7nz-15@gated-at.bofh.it> <pX1Zn-6gD-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 08/13/2015 04:40 PM, Eric Dumazet wrote:
> On Thu, 2015-08-13 at 11:13 +0200, Vlastimil Babka wrote:
>
>> Given that this apparently isn't the first case of this localhost issue,
>> I wonder if network code should just clear skb->pfmemalloc during send
>> (or maybe just send over localhost). That would be probably easier than
>> distinguish the __skb_fill_page_desc() callers for send vs receive.
>
> Would this still needed after this patch ?

Not until another corner case is discovered :) Or something passes a 
genuine pfmemalloc page to a socket (sending contents of some slab 
objects perhaps, where the slab page was allocated as pfmemalloc? Dunno 
if that can happen right now).

> It is sad we do not have a SNMP counter to at least count how often we
> drop skb because pfmemalloc is set.
>
> I'll provide such a patch.
>
>

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Thread

[PATCH] mm: make page pfmemalloc check more robust mhocko@kernel.org - 2015-08-13 11:10 +0200
  Re: [PATCH] mm: make page pfmemalloc check more robust Vlastimil Babka <vbabka@suse.cz> - 2015-08-13 11:20 +0200
    Re: [PATCH] mm: make page pfmemalloc check more robust Michal Hocko <mhocko@kernel.org> - 2015-08-13 11:40 +0200
    Re: [PATCH] mm: make page pfmemalloc check more robust Eric Dumazet <eric.dumazet@gmail.com> - 2015-08-13 16:50 +0200
      Re: [PATCH] mm: make page pfmemalloc check more robust Vlastimil Babka <vbabka@suse.cz> - 2015-08-14 15:30 +0200
  Re: [PATCH] mm: make page pfmemalloc check more robust Mel Gorman <mgorman@suse.de> - 2015-08-13 12:10 +0200

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