From: Michal Hocko <mhocko@kernel.org> To: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: linux-mm@kvack.org, Michael Ellerman <mpe@ellerman.id.au>, Vlastimil Babka <vbabka@suse.cz>, Andrew Morton <akpm@linux-foundation.org>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Reza Arbab <arbab@linux.vnet.ibm.com>, Yasuaki Ishimatsu <yasu.isimatu@gmail.com>, qiuxishi@huawei.com, Igor Mammedov <imammedo@redhat.com>, Vitaly Kuznetsov <vkuznets@redhat.com>, LKML <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 1/2] mm: drop migrate type checks from has_unmovable_pages Date: Thu, 19 Oct 2017 10:20:41 +0200 Message-ID: <20171019082041.5zudpqacaxjhe4gw@dhcp22.suse.cz> (raw) In-Reply-To: <20171019073355.GA4486@js1304-P5Q-DELUXE> On Thu 19-10-17 16:33:56, Joonsoo Kim wrote: > On Thu, Oct 19, 2017 at 09:15:03AM +0200, Michal Hocko wrote: > > On Thu 19-10-17 11:51:11, Joonsoo Kim wrote: [...] > > > Hello, > > > > > > This patch will break the CMA user. As you mentioned, CMA allocation > > > itself isn't migrateable. So, after a single page is allocated through > > > CMA allocation, has_unmovable_pages() will return true for this > > > pageblock. Then, futher CMA allocation request to this pageblock will > > > fail because it requires isolating the pageblock. > > > > Hmm, does this mean that the CMA allocation path depends on > > has_unmovable_pages to return false here even though the memory is not > > movable? This sounds really strange to me and kind of abuse of this > > Your understanding is correct. Perhaps, abuse or wrong function name. > > > function. Which path is that? Can we do the migrate type test theres? > > alloc_contig_range() -> start_isolate_page_range() -> > set_migratetype_isolate() -> has_unmovable_pages() I see. It seems that the CMA and memory hotplug have a very different view on what should happen during isolation. > We can add one argument, 'XXX' to set_migratetype_isolate() and change > it to check migrate type rather than has_unmovable_pages() if 'XXX' is > specified. Can we use the migratetype argument and do the special thing for MIGRATE_CMA? Like the following diff? --- diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h index d4cd2014fa6f..fa9db0c7b54e 100644 --- a/include/linux/page-isolation.h +++ b/include/linux/page-isolation.h @@ -30,7 +30,7 @@ static inline bool is_migrate_isolate(int migratetype) #endif bool has_unmovable_pages(struct zone *zone, struct page *page, int count, - bool skip_hwpoisoned_pages); + int migratetype, bool skip_hwpoisoned_pages); void set_pageblock_migratetype(struct page *page, int migratetype); int move_freepages_block(struct zone *zone, struct page *page, int migratetype, int *num_movable); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index bc50d746a82f..ad2ea7069d14 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7362,6 +7362,7 @@ void *__init alloc_large_system_hash(const char *tablename, * race condition. So you can't expect this function should be exact. */ bool has_unmovable_pages(struct zone *zone, struct page *page, int count, + int migratetype, bool skip_hwpoisoned_pages) { unsigned long pfn, iter, found; @@ -7373,6 +7374,15 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count, if (zone_idx(zone) == ZONE_MOVABLE) return false; + /* + * CMA allocations (alloc_contig_range) really need to mark isolate + * CMA pageblocks even when they are not movable in fact so consider + * them movable here. + */ + if (is_migrate_cma(migratetype) && + is_migrate_cma(get_pageblock_migratetype(page))) + return false; + pfn = page_to_pfn(page); for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) { unsigned long check = pfn + iter; @@ -7458,7 +7468,7 @@ bool is_pageblock_removable_nolock(struct page *page) if (!zone_spans_pfn(zone, pfn)) return false; - return !has_unmovable_pages(zone, page, 0, true); + return !has_unmovable_pages(zone, page, 0, MIGRATE_MOVABLE, true); } #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA) diff --git a/mm/page_isolation.c b/mm/page_isolation.c index 757410d9f758..8616f5332c77 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -14,7 +14,7 @@ #define CREATE_TRACE_POINTS #include <trace/events/page_isolation.h> -static int set_migratetype_isolate(struct page *page, +static int set_migratetype_isolate(struct page *page, int migratetype, bool skip_hwpoisoned_pages) { struct zone *zone; @@ -51,7 +51,7 @@ static int set_migratetype_isolate(struct page *page, * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself. * We just check MOVABLE pages. */ - if (!has_unmovable_pages(zone, page, arg.pages_found, + if (!has_unmovable_pages(zone, page, arg.pages_found, migratetype, skip_hwpoisoned_pages)) ret = 0; @@ -63,14 +63,14 @@ static int set_migratetype_isolate(struct page *page, out: if (!ret) { unsigned long nr_pages; - int migratetype = get_pageblock_migratetype(page); + int mt = get_pageblock_migratetype(page); set_pageblock_migratetype(page, MIGRATE_ISOLATE); zone->nr_isolate_pageblock++; nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE, NULL); - __mod_zone_freepage_state(zone, -nr_pages, migratetype); + __mod_zone_freepage_state(zone, -nr_pages, mt); } spin_unlock_irqrestore(&zone->lock, flags); @@ -182,7 +182,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, pfn += pageblock_nr_pages) { page = __first_valid_page(pfn, pageblock_nr_pages); if (page && - set_migratetype_isolate(page, skip_hwpoisoned_pages)) { + set_migratetype_isolate(page, migratetype, skip_hwpoisoned_pages)) { undo_pfn = pfn; goto undo; } -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply index Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-09-18 7:08 [PATCH v2 0/2] mm, memory_hotplug: redefine memory offline retry logic Michal Hocko 2017-09-18 7:08 ` [PATCH 1/2] mm, memory_hotplug: do not fail offlining too early Michal Hocko 2017-10-10 12:05 ` Michael Ellerman 2017-10-10 12:27 ` Michal Hocko 2017-10-11 2:37 ` Michael Ellerman 2017-10-11 5:19 ` Michael Ellerman 2017-10-11 14:05 ` Anshuman Khandual 2017-10-11 14:16 ` Michal Hocko 2017-10-11 6:51 ` Michal Hocko 2017-10-11 8:04 ` Vlastimil Babka 2017-10-11 8:13 ` Michal Hocko 2017-10-11 11:17 ` Vlastimil Babka 2017-10-11 11:24 ` Michal Hocko 2017-10-13 11:42 ` Michael Ellerman 2017-10-13 11:58 ` Michal Hocko 2017-10-13 12:00 ` [PATCH 1/2] mm: drop migrate type checks from has_unmovable_pages Michal Hocko 2017-10-13 12:00 ` [PATCH 2/2] mm, page_alloc: fail has_unmovable_pages when seeing reserved pages Michal Hocko 2017-10-13 12:04 ` Vlastimil Babka 2017-10-13 12:07 ` Michal Hocko 2017-10-17 13:03 ` Vlastimil Babka 2017-10-17 11:41 ` [PATCH 1/2] mm: drop migrate type checks from has_unmovable_pages Michael Ellerman 2017-10-17 12:03 ` Michal Hocko 2017-10-17 13:02 ` Vlastimil Babka 2017-10-19 2:51 ` Joonsoo Kim 2017-10-19 7:15 ` Michal Hocko 2017-10-19 7:33 ` Joonsoo Kim 2017-10-19 8:20 ` Michal Hocko [this message] 2017-10-19 12:21 ` Michal Hocko 2017-10-20 2:13 ` Joonsoo Kim 2017-10-20 5:59 ` Michal Hocko 2017-10-20 6:50 ` Joonsoo Kim 2017-10-20 7:02 ` Michal Hocko 2017-10-23 5:23 ` Joonsoo Kim 2017-10-23 8:10 ` Michal Hocko 2017-10-24 4:44 ` Joonsoo Kim 2017-10-24 7:44 ` Michal Hocko 2017-10-24 8:12 ` Vlastimil Babka 2017-10-24 12:25 ` Michal Hocko 2017-10-26 2:47 ` Joonsoo Kim 2017-10-26 7:41 ` Michal Hocko 2017-10-20 7:22 ` Xishi Qiu 2017-10-20 8:17 ` Michal Hocko 2017-10-23 5:26 ` Joonsoo Kim 2017-10-26 13:04 ` Vlastimil Babka 2017-10-26 13:59 ` Michal Hocko 2017-09-18 7:08 ` [PATCH 2/2] mm, memory_hotplug: remove timeout from __offline_memory Michal Hocko [not found] <AM3PR04MB14892A9D6D2FBCE21B8C1F0FF12B0@AM3PR04MB1489.eurprd04.prod.outlook.com> 2017-11-13 7:33 ` [PATCH 1/2] mm: drop migrate type checks from has_unmovable_pages Ran Wang 2017-11-13 11:02 ` Michal Hocko 2017-11-14 6:10 ` Ran Wang 2017-11-14 7:06 ` Michal Hocko 2017-11-14 7:45 ` Ran Wang
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