Messages in this thread | | | Date | Mon, 15 Sep 2014 11:31:06 +0900 | From | Joonsoo Kim <> | Subject | Re: [RFC PATCH v3 1/4] mm/page_alloc: fix incorrect isolation behavior by rechecking migratetype |
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On Mon, Sep 08, 2014 at 10:31:29AM +0200, Vlastimil Babka wrote: > On 08/26/2014 10:08 AM, Joonsoo Kim wrote: > > >diff --git a/mm/page_alloc.c b/mm/page_alloc.c > >index f86023b..51e0d13 100644 > >--- a/mm/page_alloc.c > >+++ b/mm/page_alloc.c > >@@ -740,9 +740,15 @@ static void free_one_page(struct zone *zone, > > if (nr_scanned) > > __mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned); > > > >+ if (unlikely(has_isolate_pageblock(zone))) { > >+ migratetype = get_pfnblock_migratetype(page, pfn); > >+ if (is_migrate_isolate(migratetype)) > >+ goto skip_counting; > >+ } > >+ __mod_zone_freepage_state(zone, 1 << order, migratetype); > >+ > >+skip_counting: > > Here, wouldn't a simple 'else __mod_zone_freepage_state...' look > better than goto + label? (same for the following 2 patches). Or > does that generate worse code?
To remove goto label, we need two __mod_zone_freepage_state() like as below. On my system, it doesn't generate worse code, but, I am not sure that this is true if more logic would be added. I think that goto + label is better.
+ if (unlikely(has_isolate_pageblock(zone))) { + migratetype = get_pfnblock_migratetype(page, pfn); + if (!is_migrate_isolate(migratetype)) + __mod_zone_freepage_state(zone, 1 << order, migratetype); + } else { + __mod_zone_freepage_state(zone, 1 << order, migratetype); }
Anyway, What do you think which one is better, either v2 or v3? Still, v3? :)
Thanks.
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