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[141.146.126.79]) by mx.google.com with ESMTPS id g203-v6si6727273itg.68.2018.04.16.19.09.35 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 16 Apr 2018 19:09:35 -0700 (PDT) From: Mike Kravetz Subject: [PATCH 2/3] mm: add find_alloc_contig_pages() interface Date: Mon, 16 Apr 2018 19:09:14 -0700 Message-Id: <20180417020915.11786-3-mike.kravetz@oracle.com> In-Reply-To: <20180417020915.11786-1-mike.kravetz@oracle.com> References: <20180417020915.11786-1-mike.kravetz@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org Cc: Reinette Chatre , Michal Hocko , Christopher Lameter , Guy Shattah , Anshuman Khandual , Michal Nazarewicz , Vlastimil Babka , David Nellans , Laura Abbott , Pavel Machek , Dave Hansen , Andrew Morton , Mike Kravetz find_alloc_contig_pages() is a new interface that attempts to locate and allocate a contiguous range of pages. It is provided as a more convenient interface than alloc_contig_range() which is currently used by CMA and gigantic huge pages. When attempting to allocate a range of pages, migration is employed if possible. There is no guarantee that the routine will succeed. So, the user must be prepared for failure and have a fall back plan. Signed-off-by: Mike Kravetz --- include/linux/gfp.h | 12 ++++++++ mm/page_alloc.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 99 insertions(+), 2 deletions(-) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 86a0d06463ab..528b194cc266 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -573,6 +573,18 @@ static inline bool pm_suspended_storage(void) extern int alloc_contig_range(unsigned long start, unsigned long end, unsigned migratetype, gfp_t gfp_mask); extern void free_contig_range(unsigned long pfn, unsigned long nr_pages); +extern struct page *find_alloc_contig_pages(unsigned int order, gfp_t gfp, + int nid, nodemask_t *nodemask); +extern void free_contig_pages(struct page *page, unsigned long nr_pages); +#else +static inline page *find_alloc_contig_pages(unsigned int order, gfp_t gfp, + int nid, nodemask_t *nodemask) +{ + return NULL; +} +static void free_contig_pages(struct page *page, unsigned long nr_pages) +{ +} #endif #ifdef CONFIG_CMA diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 0fd5e8e2456e..81070fe55c44 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -67,6 +67,7 @@ #include #include #include +#include #include #include @@ -2010,9 +2011,13 @@ static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone, { return __rmqueue_smallest(zone, order, MIGRATE_CMA); } +#define contig_alloc_migratetype_ok(migratetype) \ + ((migratetype) == MIGRATE_CMA || (migratetype) == MIGRATE_MOVABLE) #else static inline struct page *__rmqueue_cma_fallback(struct zone *zone, unsigned int order) { return NULL; } +#define contig_alloc_migratetype_ok(migratetype) \ + ((migratetype) == MIGRATE_MOVABLE) #endif /* @@ -7822,6 +7827,9 @@ int alloc_contig_range(unsigned long start, unsigned long end, }; INIT_LIST_HEAD(&cc.migratepages); + if (!contig_alloc_migratetype_ok(migratetype)) + return -EINVAL; + /* * What we do here is we mark all pageblocks in range as * MIGRATE_ISOLATE. Because pageblock and max order pages may @@ -7912,8 +7920,9 @@ int alloc_contig_range(unsigned long start, unsigned long end, /* Make sure the range is really isolated. */ if (test_pages_isolated(outer_start, end, false)) { - pr_info_ratelimited("%s: [%lx, %lx) PFNs busy\n", - __func__, outer_start, end); + if (!(migratetype == MIGRATE_MOVABLE)) /* only print for CMA */ + pr_info_ratelimited("%s: [%lx, %lx) PFNs busy\n", + __func__, outer_start, end); ret = -EBUSY; goto done; } @@ -7949,6 +7958,82 @@ void free_contig_range(unsigned long pfn, unsigned long nr_pages) } WARN(count != 0, "%ld pages are still in use!\n", count); } + +static bool contig_pfn_range_valid(struct zone *z, unsigned long start_pfn, + unsigned long nr_pages) +{ + unsigned long i, end_pfn = start_pfn + nr_pages; + struct page *page; + + for (i = start_pfn; i < end_pfn; i++) { + if (!pfn_valid(i)) + return false; + + page = pfn_to_page(i); + + if (page_zone(page) != z) + return false; + + } + + return true; +} + +/** + * find_alloc_contig_pages() -- attempt to find and allocate a contiguous + * range of pages + * @order: number of pages + * @gfp: gfp mask used to limit search as well as during compaction + * @nid: target node + * @nodemask: mask of other possible nodes + * + * Pages can be freed with a call to free_contig_pages(), or by manually + * calling __free_page() for each page allocated. + * + * Return: pointer to 'order' pages on success, or NULL if not successful. + */ +struct page *find_alloc_contig_pages(unsigned int order, gfp_t gfp, + int nid, nodemask_t *nodemask) +{ + unsigned long pfn, nr_pages, flags; + struct page *ret_page = NULL; + struct zonelist *zonelist; + struct zoneref *z; + struct zone *zone; + int rc; + + nr_pages = 1 << order; + zonelist = node_zonelist(nid, gfp); + for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp), + nodemask) { + spin_lock_irqsave(&zone->lock, flags); + pfn = ALIGN(zone->zone_start_pfn, nr_pages); + while (zone_spans_pfn(zone, pfn + nr_pages - 1)) { + if (contig_pfn_range_valid(zone, pfn, nr_pages)) { + spin_unlock_irqrestore(&zone->lock, flags); + + rc = alloc_contig_range(pfn, pfn + nr_pages, + MIGRATE_MOVABLE, gfp); + if (!rc) { + ret_page = pfn_to_page(pfn); + return ret_page; + } + spin_lock_irqsave(&zone->lock, flags); + } + pfn += nr_pages; + } + spin_unlock_irqrestore(&zone->lock, flags); + } + + return ret_page; +} +EXPORT_SYMBOL_GPL(find_alloc_contig_pages); + +void free_contig_pages(struct page *page, unsigned long nr_pages) +{ + free_contig_range(page_to_pfn(page), nr_pages); +} +EXPORT_SYMBOL_GPL(free_contig_pages); #endif #if defined CONFIG_MEMORY_HOTPLUG || defined CONFIG_CMA -- 2.13.6