Date: Tue, 28 Jul 2015 16:48:20 +0100
From: Mel Gorman <mgorman@techsingularity.net>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Linux-MM <linux-mm@kvack.org>, Johannes Weiner <hannes@cmpxchg.org>,
        Rik van Riel <riel@redhat.com>, Pintu Kumar <pintu.k@samsung.com>,
        Xishi Qiu <qiuxishi@huawei.com>, Gioh Kim <gioh.kim@lge.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 05/10] mm, page_alloc: Remove unnecessary updating of GFP
 flags during normal operation
Message-ID: <20150728154819.GE2660@techsingularity.net>
References: <1437379219-9160-1-git-send-email-mgorman@suse.com>
 <1437379219-9160-6-git-send-email-mgorman@suse.com>
 <55B78545.8000906@suse.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-15
Content-Disposition: inline
In-Reply-To: <55B78545.8000906@suse.cz>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1151
Lines: 29

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@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/