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Date: Thu, 17 Jul 2014 11:14:24 +0200 From: Vlastimil Babka <vbabka@...e.cz> To: Joonsoo Kim <iamjoonsoo.kim@....com> CC: Andrew Morton <akpm@...ux-foundation.org>, "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Rik van Riel <riel@...hat.com>, Peter Zijlstra <peterz@...radead.org>, Mel Gorman <mgorman@...e.de>, Johannes Weiner <hannes@...xchg.org>, Minchan Kim <minchan@...nel.org>, Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>, Zhang Yanfei <zhangyanfei@...fujitsu.com>, "Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>, Tang Chen <tangchen@...fujitsu.com>, Naoya Horiguchi <n-horiguchi@...jp.nec.com>, Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>, Wen Congyang <wency@...fujitsu.com>, Marek Szyprowski <m.szyprowski@...sung.com>, Michal Nazarewicz <mina86@...a86.com>, Laura Abbott <lauraa@...eaurora.org>, Heesub Shin <heesub.shin@...sung.com>, "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>, Ritesh Harjani <ritesh.list@...il.com>, t.stanislaws@...sung.com, Gioh Kim <gioh.kim@....com>, linux-mm@...ck.org, Lisa Du <cldu@...vell.com>, linux-kernel@...r.kernel.org Subject: Re: [PATCH 00/10] fix freepage count problems due to memory isolation On 07/17/2014 08:12 AM, Joonsoo Kim wrote: >> >> Hm I see. So what if it wasn't a special pcplist, but a special "free list" >> where the pages would be just linked together as on pcplist, regardless of >> order, and would not merge until the CPU that drives the memory isolation >> process decides it is safe to flush them away. That would remove the need for >> IPI's and provide the same guarantees I think. > > Looks good. It would work. I think that your solution is better than mine. > I will implement it and test. Thanks. But maybe there's still a good use for marking pages specially as isolated, and not PageBuddy with freepage_migratetype set to MIGRATE_ISOLATE. Why do we buddy-merge them anyway? I don't think CMA or memory offlining benefits from that, and it only makes the code more complex? So maybe we could split isolated buddy pages to order-0 marked as PageIsolated and have a single per-zone list instead of order-based freelists? >> Do we really need to check PageBuddy()? Could a page get marked as PageIsolate() >> but still go to normal list instead of isolate list? > > Checking PageBuddy() is used for identifying page linked in normal > list. Ah right, forgot it walks by pfn scanning, not by traversing the free list. > Thanks. > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@...ck.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@...ck.org"> email@...ck.org </a> > -- 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/
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