From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
Michal Hocko <mhocko@suse.com>,
linux-arch@vger.kernel.org
Subject: Re: [PATCH 04/17] arm: get rid of superfluous __GFP_REPEAT
Date: Wed, 1 Jun 2016 17:24:24 +0100 [thread overview]
Message-ID: <20160601162424.GD19428@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1464599699-30131-5-git-send-email-mhocko@kernel.org>
On Mon, May 30, 2016 at 11:14:46AM +0200, Michal Hocko wrote:
> From: Michal Hocko <mhocko@suse.com>
>
> __GFP_REPEAT has a rather weak semantic but since it has been introduced
> around 2.6.12 it has been ignored for low order allocations.
>
> PGALLOC_GFP uses __GFP_REPEAT but none of the allocation which uses
> this flag is for more than order-2. This means that this flag has never
> been actually useful here because it has always been used only for
> PAGE_ALLOC_COSTLY requests.
I hear what you say, but...
commit 8c65da6dc89ccb605d73773b1dd617e72982d971
Author: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Sat Nov 30 12:52:31 2013 +0000
ARM: pgd allocation: retry on failure
Make pgd allocation retry on failure; we really need this to succeed
otherwise fork() can trigger OOMs.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
and that's the change which introduced this, and it did solve a problem
for me. So I'm not happy to give an ack for this change unless someone
can tell me why adding __GFP_REPEAT back then had a beneficial effect.
Maybe there was some other bug in the MM layer in 2013 which this change
happened to solve?
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next prev parent reply other threads:[~2016-06-01 16:24 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-30 9:14 [PATCH 0/19] get rid of superfluous __GFP_REPEAT Michal Hocko
2016-05-30 9:14 ` [PATCH 01/17] tree wide: get rid of __GFP_REPEAT for order-0 allocations part I Michal Hocko
2016-05-30 9:14 ` [PATCH 02/17] x86: get rid of superfluous __GFP_REPEAT Michal Hocko
2016-05-30 9:14 ` [PATCH 03/17] x86/efi: " Michal Hocko
2016-05-30 9:14 ` [PATCH 04/17] arm: " Michal Hocko
2016-06-01 16:24 ` Russell King - ARM Linux [this message]
2016-06-02 6:32 ` Michal Hocko
2016-07-20 20:59 ` Andrew Morton
2016-05-30 9:14 ` [PATCH 05/17] arm64: " Michal Hocko
2016-05-30 9:14 ` [PATCH 06/17] arc: " Michal Hocko
2016-05-30 9:14 ` [PATCH 07/17] mips: " Michal Hocko
2016-05-30 9:14 ` [PATCH 08/17] nios2: " Michal Hocko
2016-05-30 9:14 ` [PATCH 09/17] parisc: " Michal Hocko
2016-05-30 9:14 ` [PATCH 10/17] score: " Michal Hocko
2016-05-30 9:14 ` [PATCH 11/17] powerpc: " Michal Hocko
2016-05-30 9:14 ` [PATCH 12/17] sparc: " Michal Hocko
2016-05-30 18:23 ` David Miller
2016-05-30 9:14 ` [PATCH 13/17] s390: " Michal Hocko
2016-05-30 9:14 ` [PATCH 14/17] sh: " Michal Hocko
2016-05-30 9:14 ` [PATCH 15/17] tile: " Michal Hocko
2016-05-30 9:14 ` [PATCH 16/17] unicore32: " Michal Hocko
2016-05-30 9:14 ` [PATCH 17/17] jbd2: " Michal Hocko
2016-05-30 13:09 ` Jan Kara
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