From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751078AbcFVXkQ (ORCPT ); Wed, 22 Jun 2016 19:40:16 -0400 Received: from mail-pf0-f179.google.com ([209.85.192.179]:34046 "EHLO mail-pf0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750821AbcFVXkO (ORCPT ); Wed, 22 Jun 2016 19:40:14 -0400 Date: Wed, 22 Jun 2016 16:40:10 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Andrew Morton cc: Vlastimil Babka , Minchan Kim , Joonsoo Kim , Mel Gorman , Hugh Dickins , linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org Subject: Re: [patch] mm, compaction: abort free scanner if split fails In-Reply-To: <20160622145902.9f07aa13048d4782c881cb6c@linux-foundation.org> Message-ID: References: <20160622145617.79197acff1a7e617b9d9d393@linux-foundation.org> <20160622145902.9f07aa13048d4782c881cb6c@linux-foundation.org> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 22 Jun 2016, Andrew Morton wrote: > And > mm-compaction-split-freepages-without-holding-the-zone-lock-fix.patch > churns things around some more. Now this: > > > /* Found a free page, will break it into order-0 pages */ > order = page_order(page); > isolated = __isolate_free_page(page, order); > set_page_private(page, order); > total_isolated += isolated; > list_add_tail(&page->lru, freelist); > cc->nr_freepages += isolated; > if (!strict && cc->nr_migratepages <= cc->nr_freepages) { > blockpfn += isolated; > break; > } > /* Advance to the end of split page */ > blockpfn += isolated - 1; > cursor += isolated - 1; > continue; > > isolate_fail: > > and things are looking a bit better... > This looks like it's missing the if (!isolated) break; check from mm-compaction-abort-free-scanner-if-split-fails.patch which is needed to properly terminate when the low watermark fails (and adding to freelist as Minchan mentioned before I saw this patch). I rebased mm-compaction-split-freepages-without-holding-the-zone-lock.patch as I thought it should be done and folded mm-compaction-split-freepages-without-holding-the-zone-lock-fix.patch into it for simplicity. I think this should replace mm-compaction-split-freepages-without-holding-the-zone-lock.patch in -mm. From: Joonsoo Kim We don't need to split freepages with holding the zone lock. It will cause more contention on zone lock so not desirable. Signed-off-by: Joonsoo Kim Acked-by: Vlastimil Babka --- diff --git a/include/linux/mm.h b/include/linux/mm.h --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -537,7 +537,6 @@ void __put_page(struct page *page); void put_pages_list(struct list_head *pages); void split_page(struct page *page, unsigned int order); -int split_free_page(struct page *page); /* * Compound pages have a destructor function. Provide a diff --git a/mm/compaction.c b/mm/compaction.c index ab21497..9d17b21 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -65,13 +65,31 @@ static unsigned long release_freepages(struct list_head *freelist) static void map_pages(struct list_head *list) { - struct page *page; + unsigned int i, order, nr_pages; + struct page *page, *next; + LIST_HEAD(tmp_list); + + list_for_each_entry_safe(page, next, list, lru) { + list_del(&page->lru); - list_for_each_entry(page, list, lru) { - arch_alloc_page(page, 0); - kernel_map_pages(page, 1, 1); - kasan_alloc_pages(page, 0); + order = page_private(page); + nr_pages = 1 << order; + set_page_private(page, 0); + set_page_refcounted(page); + + arch_alloc_page(page, order); + kernel_map_pages(page, nr_pages, 1); + kasan_alloc_pages(page, order); + if (order) + split_page(page, order); + + for (i = 0; i < nr_pages; i++) { + list_add(&page->lru, &tmp_list); + page++; + } } + + list_splice(&tmp_list, list); } static inline bool migrate_async_suitable(int migratetype) @@ -406,12 +424,13 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, unsigned long flags = 0; bool locked = false; unsigned long blockpfn = *start_pfn; + unsigned int order; cursor = pfn_to_page(blockpfn); /* Isolate free pages. */ for (; blockpfn < end_pfn; blockpfn++, cursor++) { - int isolated, i; + int isolated; struct page *page = cursor; /* @@ -477,17 +496,17 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, goto isolate_fail; } - /* Found a free page, break it into order-0 pages */ - isolated = split_free_page(page); + /* Found a free page, will break it into order-0 pages */ + order = page_order(page); + isolated = __isolate_free_page(page, order); if (!isolated) break; + set_page_private(page, order); total_isolated += isolated; cc->nr_freepages += isolated; - for (i = 0; i < isolated; i++) { - list_add(&page->lru, freelist); - page++; - } + list_add_tail(&page->lru, freelist); + if (!strict && cc->nr_migratepages <= cc->nr_freepages) { blockpfn += isolated; break; @@ -606,7 +625,7 @@ isolate_freepages_range(struct compact_control *cc, */ } - /* split_free_page does not map the pages */ + /* __isolate_free_page() does not map the pages */ map_pages(&freelist); if (pfn < end_pfn) { @@ -1113,7 +1132,7 @@ static void isolate_freepages(struct compact_control *cc) } } - /* split_free_page does not map the pages */ + /* __isolate_free_page() does not map the pages */ map_pages(freelist); /* diff --git a/mm/page_alloc.c b/mm/page_alloc.c --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2560,33 +2560,6 @@ int __isolate_free_page(struct page *page, unsigned int order) } /* - * Similar to split_page except the page is already free. As this is only - * being used for migration, the migratetype of the block also changes. - * As this is called with interrupts disabled, the caller is responsible - * for calling arch_alloc_page() and kernel_map_page() after interrupts - * are enabled. - * - * Note: this is probably too low level an operation for use in drivers. - * Please consult with lkml before using this in your driver. - */ -int split_free_page(struct page *page) -{ - unsigned int order; - int nr_pages; - - order = page_order(page); - - nr_pages = __isolate_free_page(page, order); - if (!nr_pages) - return 0; - - /* Split into individual pages */ - set_page_refcounted(page); - split_page(page, order); - return nr_pages; -} - -/* * Update NUMA hit/miss statistics * * Must be called with interrupts disabled. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 22 Jun 2016 16:40:10 -0700 (PDT) From: David Rientjes To: Andrew Morton cc: Vlastimil Babka , Minchan Kim , Joonsoo Kim , Mel Gorman , Hugh Dickins , linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org Subject: Re: [patch] mm, compaction: abort free scanner if split fails In-Reply-To: <20160622145902.9f07aa13048d4782c881cb6c@linux-foundation.org> Message-ID: References: <20160622145617.79197acff1a7e617b9d9d393@linux-foundation.org> <20160622145902.9f07aa13048d4782c881cb6c@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: On Wed, 22 Jun 2016, Andrew Morton wrote: > And > mm-compaction-split-freepages-without-holding-the-zone-lock-fix.patch > churns things around some more. Now this: > > > /* Found a free page, will break it into order-0 pages */ > order = page_order(page); > isolated = __isolate_free_page(page, order); > set_page_private(page, order); > total_isolated += isolated; > list_add_tail(&page->lru, freelist); > cc->nr_freepages += isolated; > if (!strict && cc->nr_migratepages <= cc->nr_freepages) { > blockpfn += isolated; > break; > } > /* Advance to the end of split page */ > blockpfn += isolated - 1; > cursor += isolated - 1; > continue; > > isolate_fail: > > and things are looking a bit better... > This looks like it's missing the if (!isolated) break; check from mm-compaction-abort-free-scanner-if-split-fails.patch which is needed to properly terminate when the low watermark fails (and adding to freelist as Minchan mentioned before I saw this patch). I rebased mm-compaction-split-freepages-without-holding-the-zone-lock.patch as I thought it should be done and folded mm-compaction-split-freepages-without-holding-the-zone-lock-fix.patch into it for simplicity. I think this should replace mm-compaction-split-freepages-without-holding-the-zone-lock.patch in -mm. From: Joonsoo Kim We don't need to split freepages with holding the zone lock. It will cause more contention on zone lock so not desirable. Signed-off-by: Joonsoo Kim Acked-by: Vlastimil Babka --- diff --git a/include/linux/mm.h b/include/linux/mm.h --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -537,7 +537,6 @@ void __put_page(struct page *page); void put_pages_list(struct list_head *pages); void split_page(struct page *page, unsigned int order); -int split_free_page(struct page *page); /* * Compound pages have a destructor function. Provide a diff --git a/mm/compaction.c b/mm/compaction.c index ab21497..9d17b21 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -65,13 +65,31 @@ static unsigned long release_freepages(struct list_head *freelist) static void map_pages(struct list_head *list) { - struct page *page; + unsigned int i, order, nr_pages; + struct page *page, *next; + LIST_HEAD(tmp_list); + + list_for_each_entry_safe(page, next, list, lru) { + list_del(&page->lru); - list_for_each_entry(page, list, lru) { - arch_alloc_page(page, 0); - kernel_map_pages(page, 1, 1); - kasan_alloc_pages(page, 0); + order = page_private(page); + nr_pages = 1 << order; + set_page_private(page, 0); + set_page_refcounted(page); + + arch_alloc_page(page, order); + kernel_map_pages(page, nr_pages, 1); + kasan_alloc_pages(page, order); + if (order) + split_page(page, order); + + for (i = 0; i < nr_pages; i++) { + list_add(&page->lru, &tmp_list); + page++; + } } + + list_splice(&tmp_list, list); } static inline bool migrate_async_suitable(int migratetype) @@ -406,12 +424,13 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, unsigned long flags = 0; bool locked = false; unsigned long blockpfn = *start_pfn; + unsigned int order; cursor = pfn_to_page(blockpfn); /* Isolate free pages. */ for (; blockpfn < end_pfn; blockpfn++, cursor++) { - int isolated, i; + int isolated; struct page *page = cursor; /* @@ -477,17 +496,17 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, goto isolate_fail; } - /* Found a free page, break it into order-0 pages */ - isolated = split_free_page(page); + /* Found a free page, will break it into order-0 pages */ + order = page_order(page); + isolated = __isolate_free_page(page, order); if (!isolated) break; + set_page_private(page, order); total_isolated += isolated; cc->nr_freepages += isolated; - for (i = 0; i < isolated; i++) { - list_add(&page->lru, freelist); - page++; - } + list_add_tail(&page->lru, freelist); + if (!strict && cc->nr_migratepages <= cc->nr_freepages) { blockpfn += isolated; break; @@ -606,7 +625,7 @@ isolate_freepages_range(struct compact_control *cc, */ } - /* split_free_page does not map the pages */ + /* __isolate_free_page() does not map the pages */ map_pages(&freelist); if (pfn < end_pfn) { @@ -1113,7 +1132,7 @@ static void isolate_freepages(struct compact_control *cc) } } - /* split_free_page does not map the pages */ + /* __isolate_free_page() does not map the pages */ map_pages(freelist); /* diff --git a/mm/page_alloc.c b/mm/page_alloc.c --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2560,33 +2560,6 @@ int __isolate_free_page(struct page *page, unsigned int order) } /* - * Similar to split_page except the page is already free. As this is only - * being used for migration, the migratetype of the block also changes. - * As this is called with interrupts disabled, the caller is responsible - * for calling arch_alloc_page() and kernel_map_page() after interrupts - * are enabled. - * - * Note: this is probably too low level an operation for use in drivers. - * Please consult with lkml before using this in your driver. - */ -int split_free_page(struct page *page) -{ - unsigned int order; - int nr_pages; - - order = page_order(page); - - nr_pages = __isolate_free_page(page, order); - if (!nr_pages) - return 0; - - /* Split into individual pages */ - set_page_refcounted(page); - split_page(page, order); - return nr_pages; -} - -/* * Update NUMA hit/miss statistics * * Must be called with interrupts disabled. -- 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: email@kvack.org