From: Mel Gorman <mgorman@techsingularity.net>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Rik van Riel <riel@redhat.com>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Michal Hocko <mhocko@kernel.org>, Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 12/12] mm, page_alloc: Only enforce watermarks for order-0 allocations
Date: Wed, 26 Aug 2015 15:53:18 +0100 [thread overview]
Message-ID: <20150826145318.GP12432@techsingularity.net> (raw)
In-Reply-To: <55DDC23F.8020004@suse.cz>
On Wed, Aug 26, 2015 at 03:42:23PM +0200, Vlastimil Babka wrote:
> >@@ -2309,22 +2311,30 @@ static bool __zone_watermark_ok(struct zone *z, unsigned int order,
> > #ifdef CONFIG_CMA
> > /* If allocation can't use CMA areas don't use free CMA pages */
> > if (!(alloc_flags & ALLOC_CMA))
> >- free_cma = zone_page_state(z, NR_FREE_CMA_PAGES);
> >+ free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);
> > #endif
> >
> >- if (free_pages - free_cma <= min + z->lowmem_reserve[classzone_idx])
> >+ if (free_pages <= min + z->lowmem_reserve[classzone_idx])
> > return false;
> >- for (o = 0; o < order; o++) {
> >- /* At the next order, this order's pages become unavailable */
> >- free_pages -= z->free_area[o].nr_free << o;
> >
> >- /* Require fewer higher order pages to be free */
> >- min >>= 1;
> >+ /* order-0 watermarks are ok */
> >+ if (!order)
> >+ return true;
> >+
> >+ /* Check at least one high-order page is free */
> >+ for (o = order; o < MAX_ORDER; o++) {
> >+ struct free_area *area = &z->free_area[o];
> >+ int mt;
> >+
> >+ if (atomic && area->nr_free)
> >+ return true;
> >
> >- if (free_pages <= min)
> >- return false;
> >+ for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
> >+ if (!list_empty(&area->free_list[mt]))
> >+ return true;
> >+ }
>
> I think we really need something like this here:
>
> #ifdef CONFIG_CMA
> if (alloc_flags & ALLOC_CMA)) &&
> !list_empty(&area->free_list[MIGRATE_CMA])
> return true;
> #endif
>
> This is not about CMA and high-order atomic allocations being used at the
> same time. This is about high-order MIGRATE_MOVABLE allocations (that set
> ALLOC_CMA) failing to use MIGRATE_CMA pageblocks, which they should be
> allowed to use. It's complementary to the existing free_pages adjustment
> above.
>
> Maybe there's not many high-order MIGRATE_MOVABLE allocations today, but
> they might increase with the driver migration framework. So why set up us a
> bomb.
>
Ok, that seems sensible. Will apply this hunk on top
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 1a4169be1498..10f25bf18665 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2337,6 +2337,13 @@ static bool __zone_watermark_ok(struct zone *z, unsigned int order,
if (!list_empty(&area->free_list[mt]))
return true;
}
+
+#ifdef CONFIG_CMA
+ if ((alloc_flags & ALLOC_CMA) &&
+ !list_empty(&area->free_list[MIGRATE_CMA])) {
+ return true;
+ }
+#endif
}
return false;
}
next prev parent reply other threads:[~2015-08-26 14:53 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-24 12:09 [PATCH 00/12] Remove zonelist cache and high-order watermark checking v3 Mel Gorman
2015-08-24 12:09 ` [PATCH 01/12] mm, page_alloc: Remove unnecessary parameter from zone_watermark_ok_safe Mel Gorman
2015-08-24 12:09 ` [PATCH 02/12] mm, page_alloc: Remove unnecessary recalculations for dirty zone balancing Mel Gorman
2015-08-24 12:09 ` [PATCH 03/12] mm, page_alloc: Remove unnecessary taking of a seqlock when cpusets are disabled Mel Gorman
2015-08-26 10:25 ` Michal Hocko
2015-08-24 12:09 ` [PATCH 04/12] mm, page_alloc: Only check cpusets when one exists that can be mem-controlled Mel Gorman
2015-08-24 12:37 ` Vlastimil Babka
2015-08-24 13:16 ` Mel Gorman
2015-08-24 20:53 ` Vlastimil Babka
2015-08-25 10:33 ` Mel Gorman
2015-08-25 11:09 ` Vlastimil Babka
2015-08-26 13:41 ` Mel Gorman
2015-08-26 10:46 ` Michal Hocko
2015-08-24 12:09 ` [PATCH 05/12] mm, page_alloc: Remove unecessary recheck of nodemask Mel Gorman
2015-08-25 14:32 ` Vlastimil Babka
2015-08-24 12:09 ` [PATCH 06/12] mm, page_alloc: Use masks and shifts when converting GFP flags to migrate types Mel Gorman
2015-08-25 14:36 ` Vlastimil Babka
2015-08-24 12:09 ` [PATCH 07/12] mm, page_alloc: Distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd Mel Gorman
2015-08-24 18:29 ` Mel Gorman
2015-08-25 15:37 ` Vlastimil Babka
2015-08-26 14:45 ` Mel Gorman
2015-08-26 16:24 ` Vlastimil Babka
2015-08-26 18:10 ` Mel Gorman
2015-08-27 9:18 ` Vlastimil Babka
2015-08-25 15:48 ` Vlastimil Babka
2015-08-26 13:05 ` Michal Hocko
2015-09-08 6:49 ` Joonsoo Kim
2015-09-09 12:22 ` Mel Gorman
2015-09-18 6:25 ` Joonsoo Kim
2015-08-24 12:09 ` [PATCH 08/12] mm, page_alloc: Rename __GFP_WAIT to __GFP_RECLAIM Mel Gorman
2015-08-26 12:19 ` Vlastimil Babka
2015-08-24 12:09 ` [PATCH 09/12] mm, page_alloc: Delete the zonelist_cache Mel Gorman
2015-08-24 12:29 ` [PATCH 10/12] mm, page_alloc: Remove MIGRATE_RESERVE Mel Gorman
2015-08-24 12:29 ` [PATCH 11/12] mm, page_alloc: Reserve pageblocks for high-order atomic allocations on demand Mel Gorman
2015-08-26 12:44 ` Vlastimil Babka
2015-08-26 14:53 ` Michal Hocko
2015-08-26 15:38 ` Mel Gorman
2015-09-08 8:01 ` Joonsoo Kim
2015-09-09 12:32 ` Mel Gorman
2015-09-18 6:38 ` Joonsoo Kim
2015-09-21 10:51 ` Mel Gorman
2015-08-24 12:30 ` [PATCH 12/12] mm, page_alloc: Only enforce watermarks for order-0 allocations Mel Gorman
2015-08-26 13:42 ` Vlastimil Babka
2015-08-26 14:53 ` Mel Gorman [this message]
2015-08-28 12:10 ` Michal Hocko
2015-08-28 14:12 ` Mel Gorman
2015-09-08 8:26 ` Joonsoo Kim
2015-09-09 12:39 ` Mel Gorman
2015-09-18 6:56 ` Joonsoo Kim
2015-09-21 10:51 ` Mel Gorman
2015-09-30 8:51 ` Vitaly Wool
2015-09-30 13:52 ` Vlastimil Babka
2015-09-30 14:16 ` Vitaly Wool
2015-09-30 14:43 ` Vlastimil Babka
2015-09-30 15:18 ` Mel Gorman
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