linux-kernel - Re: [PATCH 05/10] mm, page_alloc: Remove unnecessary updating of GFP flags during normal operation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150728154819.GE2660@techsingularity.net>
Date:	Tue, 28 Jul 2015 16:48:20 +0100
From:	Mel Gorman <mgorman@...hsingularity.net>
To:	Vlastimil Babka <vbabka@...e.cz>
Cc:	Linux-MM <linux-mm@...ck.org>,
	Johannes Weiner <hannes@...xchg.org>,
	Rik van Riel <riel@...hat.com>,
	Pintu Kumar <pintu.k@...sung.com>,
	Xishi Qiu <qiuxishi@...wei.com>, Gioh Kim <gioh.kim@....com>,
	LKML <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH 05/10] mm, page_alloc: Remove unnecessary updating of GFP
 flags during normal operation

On Tue, Jul 28, 2015 at 03:36:05PM +0200, Vlastimil Babka wrote:
> >--- a/mm/page_alloc.c
> >+++ b/mm/page_alloc.c
> >@@ -124,7 +124,9 @@ unsigned long totalcma_pages __read_mostly;
> >  unsigned long dirty_balance_reserve __read_mostly;
> >
> >  int percpu_pagelist_fraction;
> >-gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
> >+
> >+gfp_t __gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
> >+struct static_key gfp_restricted_key __read_mostly = STATIC_KEY_INIT_TRUE;
> 
> ... and here it's combined with STATIC_KEY_INIT_TRUE. I've suspected
> that this is not allowed, which Peter confirmed on IRC.
> 

Thanks because I was not aware of hazards of that nature. I'll drop the
jump-label related patches from the series until the patches related to
the correct idiom are finalised. The micro-optimisations are not the
main point of this series and the savings are tiny.

-- 
Mel Gorman
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/