From: Vlastimil Babka <vbabka@suse.cz> To: Michal Hocko <mhocko@kernel.org>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org, Michael Ellerman <mpe@ellerman.id.au>, 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, 26 Oct 2017 15:04:55 +0200 [thread overview] Message-ID: <76e4290b-47b9-6c6f-bce6-befc30713083@suse.cz> (raw) In-Reply-To: <20171019122118.y6cndierwl2vnguj@dhcp22.suse.cz> On 10/19/2017 02:21 PM, Michal Hocko wrote: > On Thu 19-10-17 10:20:41, Michal Hocko wrote: >> 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? > > And with the full changelog. > --- > From 8cbd811d741f5dd93d1b21bb3ef94482a4d0bd32 Mon Sep 17 00:00:00 2001 > From: Michal Hocko <mhocko@suse.com> > Date: Thu, 19 Oct 2017 14:14:02 +0200 > Subject: [PATCH] mm: distinguish CMA and MOVABLE isolation in > has_unmovable_pages > > Joonsoo has noticed that "mm: drop migrate type checks from > has_unmovable_pages" would break CMA allocator because it relies on > has_unmovable_pages returning false even for CMA pageblocks which in > fact don't have to be movable: > alloc_contig_range > start_isolate_page_range > set_migratetype_isolate > has_unmovable_pages > > This is a result of the code sharing between CMA and memory hotplug > while each one has a different idea of what has_unmovable_pages should > return. This is unfortunate but fixing it properly would require a lot > of code duplication. > > Fix the issue by introducing the requested migrate type argument > and special case MIGRATE_CMA case where CMA page blocks are handled > properly. This will work for memory hotplug because it requires > MIGRATE_MOVABLE. > > Reported-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> > Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> > --- > include/linux/page-isolation.h | 2 +- > mm/page_alloc.c | 12 +++++++++++- > mm/page_isolation.c | 10 +++++----- > 3 files changed, 17 insertions(+), 7 deletions(-) > > 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 5b4d85ae445c..259aeb22462f 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -7344,6 +7344,7 @@ 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; > @@ -7356,6 +7357,15 @@ 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; > @@ -7441,7 +7451,7 @@ 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; > } >
WARNING: multiple messages have this Message-ID (diff)
From: Vlastimil Babka <vbabka@suse.cz> To: Michal Hocko <mhocko@kernel.org>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org, Michael Ellerman <mpe@ellerman.id.au>, 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, 26 Oct 2017 15:04:55 +0200 [thread overview] Message-ID: <76e4290b-47b9-6c6f-bce6-befc30713083@suse.cz> (raw) In-Reply-To: <20171019122118.y6cndierwl2vnguj@dhcp22.suse.cz> On 10/19/2017 02:21 PM, Michal Hocko wrote: > On Thu 19-10-17 10:20:41, Michal Hocko wrote: >> 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? > > And with the full changelog. > --- > From 8cbd811d741f5dd93d1b21bb3ef94482a4d0bd32 Mon Sep 17 00:00:00 2001 > From: Michal Hocko <mhocko@suse.com> > Date: Thu, 19 Oct 2017 14:14:02 +0200 > Subject: [PATCH] mm: distinguish CMA and MOVABLE isolation in > has_unmovable_pages > > Joonsoo has noticed that "mm: drop migrate type checks from > has_unmovable_pages" would break CMA allocator because it relies on > has_unmovable_pages returning false even for CMA pageblocks which in > fact don't have to be movable: > alloc_contig_range > start_isolate_page_range > set_migratetype_isolate > has_unmovable_pages > > This is a result of the code sharing between CMA and memory hotplug > while each one has a different idea of what has_unmovable_pages should > return. This is unfortunate but fixing it properly would require a lot > of code duplication. > > Fix the issue by introducing the requested migrate type argument > and special case MIGRATE_CMA case where CMA page blocks are handled > properly. This will work for memory hotplug because it requires > MIGRATE_MOVABLE. > > Reported-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> > Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> > --- > include/linux/page-isolation.h | 2 +- > mm/page_alloc.c | 12 +++++++++++- > mm/page_isolation.c | 10 +++++----- > 3 files changed, 17 insertions(+), 7 deletions(-) > > 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 5b4d85ae445c..259aeb22462f 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -7344,6 +7344,7 @@ 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; > @@ -7356,6 +7357,15 @@ 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; > @@ -7441,7 +7451,7 @@ 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; > } > -- 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 other threads:[~2017-10-26 13:05 UTC|newest] Thread overview: 102+ 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 ` Michal Hocko 2017-09-18 7:08 ` [PATCH 1/2] mm, memory_hotplug: do not fail offlining too early Michal Hocko 2017-09-18 7:08 ` Michal Hocko 2017-10-10 12:05 ` Michael Ellerman 2017-10-10 12:05 ` Michael Ellerman 2017-10-10 12:27 ` Michal Hocko 2017-10-10 12:27 ` Michal Hocko 2017-10-11 2:37 ` Michael Ellerman 2017-10-11 2:37 ` Michael Ellerman 2017-10-11 5:19 ` Michael Ellerman 2017-10-11 5:19 ` Michael Ellerman 2017-10-11 14:05 ` Anshuman Khandual 2017-10-11 14:05 ` Anshuman Khandual 2017-10-11 14:16 ` Michal Hocko 2017-10-11 14:16 ` Michal Hocko 2017-10-11 6:51 ` Michal Hocko 2017-10-11 6:51 ` Michal Hocko 2017-10-11 8:04 ` Vlastimil Babka 2017-10-11 8:04 ` Vlastimil Babka 2017-10-11 8:13 ` Michal Hocko 2017-10-11 8:13 ` Michal Hocko 2017-10-11 11:17 ` Vlastimil Babka 2017-10-11 11:17 ` Vlastimil Babka 2017-10-11 11:24 ` Michal Hocko 2017-10-11 11:24 ` Michal Hocko 2017-10-13 11:42 ` Michael Ellerman 2017-10-13 11:42 ` Michael Ellerman 2017-10-13 11:58 ` Michal Hocko 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 ` 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 12:00 ` Michal Hocko 2017-10-13 12:04 ` Vlastimil Babka 2017-10-13 12:04 ` Vlastimil Babka 2017-10-13 12:07 ` Michal Hocko 2017-10-13 12:07 ` Michal Hocko 2017-10-17 13:03 ` Vlastimil Babka 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 11:41 ` Michael Ellerman 2017-10-17 12:03 ` Michal Hocko 2017-10-17 12:03 ` Michal Hocko 2017-10-17 13:02 ` Vlastimil Babka 2017-10-17 13:02 ` Vlastimil Babka 2017-10-19 2:51 ` Joonsoo Kim 2017-10-19 2:51 ` Joonsoo Kim 2017-10-19 7:15 ` Michal Hocko 2017-10-19 7:15 ` Michal Hocko 2017-10-19 7:33 ` Joonsoo Kim 2017-10-19 7:33 ` Joonsoo Kim 2017-10-19 8:20 ` Michal Hocko 2017-10-19 8:20 ` Michal Hocko 2017-10-19 12:21 ` Michal Hocko 2017-10-19 12:21 ` Michal Hocko 2017-10-20 2:13 ` Joonsoo Kim 2017-10-20 2:13 ` Joonsoo Kim 2017-10-20 5:59 ` Michal Hocko 2017-10-20 5:59 ` Michal Hocko 2017-10-20 6:50 ` Joonsoo Kim 2017-10-20 6:50 ` Joonsoo Kim 2017-10-20 7:02 ` Michal Hocko 2017-10-20 7:02 ` Michal Hocko 2017-10-23 5:23 ` Joonsoo Kim 2017-10-23 5:23 ` Joonsoo Kim 2017-10-23 8:10 ` Michal Hocko 2017-10-23 8:10 ` Michal Hocko 2017-10-24 4:44 ` Joonsoo Kim 2017-10-24 4:44 ` Joonsoo Kim 2017-10-24 7:44 ` Michal Hocko 2017-10-24 7:44 ` Michal Hocko 2017-10-24 8:12 ` Vlastimil Babka 2017-10-24 8:12 ` Vlastimil Babka 2017-10-24 12:25 ` Michal Hocko 2017-10-24 12:25 ` Michal Hocko 2017-10-26 2:47 ` Joonsoo Kim 2017-10-26 2:47 ` Joonsoo Kim 2017-10-26 7:41 ` Michal Hocko 2017-10-26 7:41 ` Michal Hocko 2017-10-20 7:22 ` Xishi Qiu 2017-10-20 7:22 ` Xishi Qiu 2017-10-20 8:17 ` Michal Hocko 2017-10-20 8:17 ` Michal Hocko 2017-10-23 5:26 ` Joonsoo Kim 2017-10-23 5:26 ` Joonsoo Kim 2017-10-26 13:04 ` Vlastimil Babka [this message] 2017-10-26 13:04 ` Vlastimil Babka 2017-10-26 13:59 ` Michal Hocko 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 2017-09-18 7:08 ` 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 7:33 ` Ran Wang 2017-11-13 11:02 ` Michal Hocko 2017-11-13 11:02 ` Michal Hocko 2017-11-14 6:10 ` Ran Wang 2017-11-14 6:10 ` Ran Wang 2017-11-14 7:06 ` Michal Hocko 2017-11-14 7:06 ` Michal Hocko 2017-11-14 7:45 ` Ran Wang 2017-11-14 7:45 ` Ran Wang
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