From: Leon Romanovsky <leon@leon.nu>
To: Mel Gorman <mgorman@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
Linux-FSDevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH] mm: page_alloc: Fix setting of ZONE_FAIR_DEPLETED on UP
Date: Sun, 7 Sep 2014 09:32:20 +0300 [thread overview]
Message-ID: <CALq1K=JO2b-=iq40RRvK8JFFbrzyH5EyAp5jyS50CeV0P3eQcA@mail.gmail.com> (raw)
In-Reply-To: <20140905101451.GF17501@suse.de>
Hi Mel,
> __mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order));
> - if (zone_page_state(zone, NR_ALLOC_BATCH) == 0 &&
> + if (zone_page_state(zone, NR_ALLOC_BATCH) <= 0 &&
zone_page_state is declared to return unsigned long value [1], so it
should never be below 0.
So interesting question: what zone_page_state will return for negative
atomic_long_read(&zone->vm_stat[item]) ?
130 static inline unsigned long zone_page_state(struct zone *zone,
131 enum zone_stat_item item)
132 {
133 long x = atomic_long_read(&zone->vm_stat[item]);
134 #ifdef CONFIG_SMP
135 if (x < 0)
136 x = 0;
137 #endif
138 return x;
139 }
[1] https://git.kernel.org/cgit/linux/kernel/git/mhocko/mm.git/tree/include/linux/vmstat.h#n130
--
Leon Romanovsky | Independent Linux Consultant
www.leon.nu | leon@leon.nu
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next prev parent reply other threads:[~2014-09-07 6:32 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-09 8:13 [PATCH 0/5] Reduce sequential read overhead Mel Gorman
2014-07-09 8:13 ` [PATCH 1/6] mm: pagemap: Avoid unnecessary overhead when tracepoints are deactivated Mel Gorman
2014-07-10 12:01 ` Johannes Weiner
2014-07-09 8:13 ` [PATCH 2/6] mm: Rearrange zone fields into read-only, page alloc, statistics and page reclaim lines Mel Gorman
2014-07-10 12:06 ` Johannes Weiner
2014-07-09 8:13 ` [PATCH 3/6] mm: Move zone->pages_scanned into a vmstat counter Mel Gorman
2014-07-10 12:08 ` Johannes Weiner
2014-07-09 8:13 ` [PATCH 4/6] mm: vmscan: Only update per-cpu thresholds for online CPU Mel Gorman
2014-07-10 12:09 ` Johannes Weiner
2014-07-09 8:13 ` [PATCH 5/6] mm: page_alloc: Abort fair zone allocation policy when remotes nodes are encountered Mel Gorman
2014-07-10 12:14 ` Johannes Weiner
2014-07-10 12:44 ` Mel Gorman
2014-07-09 8:13 ` [PATCH 6/6] mm: page_alloc: Reduce cost of the fair zone allocation policy Mel Gorman
2014-07-10 12:18 ` Johannes Weiner
2014-08-08 15:27 ` Vlastimil Babka
2014-08-11 12:12 ` Mel Gorman
2014-08-11 12:34 ` Vlastimil Babka
2014-09-02 14:01 ` Johannes Weiner
2014-09-05 10:14 ` [PATCH] mm: page_alloc: Fix setting of ZONE_FAIR_DEPLETED on UP Mel Gorman
2014-09-07 6:32 ` Leon Romanovsky [this message]
2014-09-08 11:57 ` [PATCH] mm: page_alloc: Fix setting of ZONE_FAIR_DEPLETED on UP v2 Mel Gorman
2014-09-09 8:17 ` Leon Romanovsky
2014-09-09 19:53 ` Andrew Morton
2014-09-10 9:16 ` Mel Gorman
2014-09-10 20:32 ` Johannes Weiner
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