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From: Michal Hocko <mhocko@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, Michael Ellerman <mpe@ellerman.id.au>,
	Vlastimil Babka <vbabka@suse.cz>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	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 15:59:32 +0200	[thread overview]
Message-ID: <20171026135932.p5st4z7t6akmmxkf@dhcp22.suse.cz> (raw)
In-Reply-To: <20171019122118.y6cndierwl2vnguj@dhcp22.suse.cz>

On Thu 19-10-17 14:21:18, Michal Hocko wrote:
[...]
> 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>
> ---

Andrew,
could you add this one to the bundle as well? After
mm-drop-migrate-type-checks-from-has_unmovable_pages.patch, please.

Joonsoo would like to see a larger change in this area [1] but I think
we need to think those much more through [2] and Joonsoo agreed to take
the simpler patch first [3].

Thanks!

[1] http://lkml.kernel.org/r/20171024044423.GA31424@js1304-P5Q-DELUXE
[2] http://lkml.kernel.org/r/20171024122526.3kmabkcbmj4johli@dhcp22.suse.cz
[3] http://lkml.kernel.org/r/20171026024707.GA11791@js1304-P5Q-DELUXE

>  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;
>  		}
> -- 
> 2.14.2
> 
> -- 
> Michal Hocko
> SUSE Labs

-- 
Michal Hocko
SUSE Labs

WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, Michael Ellerman <mpe@ellerman.id.au>,
	Vlastimil Babka <vbabka@suse.cz>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	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 15:59:32 +0200	[thread overview]
Message-ID: <20171026135932.p5st4z7t6akmmxkf@dhcp22.suse.cz> (raw)
In-Reply-To: <20171019122118.y6cndierwl2vnguj@dhcp22.suse.cz>

On Thu 19-10-17 14:21:18, Michal Hocko wrote:
[...]
> 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>
> ---

Andrew,
could you add this one to the bundle as well? After
mm-drop-migrate-type-checks-from-has_unmovable_pages.patch, please.

Joonsoo would like to see a larger change in this area [1] but I think
we need to think those much more through [2] and Joonsoo agreed to take
the simpler patch first [3].

Thanks!

[1] http://lkml.kernel.org/r/20171024044423.GA31424@js1304-P5Q-DELUXE
[2] http://lkml.kernel.org/r/20171024122526.3kmabkcbmj4johli@dhcp22.suse.cz
[3] http://lkml.kernel.org/r/20171026024707.GA11791@js1304-P5Q-DELUXE

>  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;
>  		}
> -- 
> 2.14.2
> 
> -- 
> Michal Hocko
> SUSE Labs

-- 
Michal Hocko
SUSE Labs

--
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  parent reply	other threads:[~2017-10-26 13:59 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
2017-10-26 13:04                               ` Vlastimil Babka
2017-10-26 13:59                             ` Michal Hocko [this message]
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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