From mboxrd@z Thu Jan 1 00:00:00 1970 From: mina86@mina86.com (Michal Nazarewicz) Date: Mon, 30 Jan 2012 14:06:50 +0100 Subject: [PATCH 08/15] mm: mmzone: MIGRATE_CMA migration type added In-Reply-To: <20120130123542.GL25268@csn.ul.ie> References: <1327568457-27734-1-git-send-email-m.szyprowski@samsung.com> <1327568457-27734-9-git-send-email-m.szyprowski@samsung.com> <20120130123542.GL25268@csn.ul.ie> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org > On Thu, Jan 26, 2012 at 10:00:50AM +0100, Marek Szyprowski wrote: >> From: Michal Nazarewicz >> @@ -875,10 +895,15 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order, >> * This array describes the order lists are fallen back to when >> * the free lists for the desirable migrate type are depleted >> */ >> -static int fallbacks[MIGRATE_TYPES][3] = { >> +static int fallbacks[MIGRATE_TYPES][4] = { >> [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE }, >> [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE }, >> +#ifdef CONFIG_CMA >> + [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_CMA , MIGRATE_RESERVE }, On Mon, 30 Jan 2012 13:35:42 +0100, Mel Gorman wrote: > This is a curious choice. MIGRATE_CMA is allowed to contain movable > pages. By using MIGRATE_RECLAIMABLE and MIGRATE_UNMOVABLE for movable > pages instead of MIGRATE_CMA, you increase the changes that unmovable > pages will need to use MIGRATE_MOVABLE in the future which impacts > fragmentation avoidance. I would recommend that you change this to > > { MIGRATE_CMA, MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE } At the beginning the idea was to try hard not to get pages from MIGRATE_CMA allocated at all, thus it was put at the end of the fallbacks list, but on a busy system this probably won't help anyway, so I'll change it per your suggestion. >> @@ -1017,11 +1049,14 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype) >> rmv_page_order(page); >> >> /* Take ownership for orders >= pageblock_order */ >> - if (current_order >= pageblock_order) >> + if (current_order >= pageblock_order && >> + !is_pageblock_cma(page)) >> change_pageblock_range(page, current_order, >> start_migratetype); >> >> - expand(zone, page, order, current_order, area, migratetype); >> + expand(zone, page, order, current_order, area, >> + is_migrate_cma(start_migratetype) >> + ? start_migratetype : migratetype); >> > > What is this check meant to be doing? > > start_migratetype is determined by allocflags_to_migratetype() and > that never will be MIGRATE_CMA so is_migrate_cma(start_migratetype) > should always be false. Right, thanks! This should be the other way around, ie.: + expand(zone, page, order, current_order, area, + is_migrate_cma(migratetype) + ? migratetype : start_migratetype); I'll fix this and the calls to is_pageblock_cma(). -- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Micha? ?mina86? Nazarewicz (o o) ooo +------------------ooO--(_)--Ooo--