[PATCH V6 1/2] mm/page_alloc: Make alloc_gigantic_page() available for general use
From: Anshuman Khandual <hidden>
Date: 2019-10-15 09:21:46
Also in:
linux-arm-kernel, linux-mm
Subsystem:
hugetlb subsystem, memory management, memory management - core, memory management - page allocator, the rest · Maintainers:
Muchun Song, Oscar Salvador, Andrew Morton, David Hildenbrand, Vlastimil Babka, Linus Torvalds
alloc_gigantic_page() implements an allocation method where it scans over various zones looking for a large contiguous memory block which could not have been allocated through the buddy allocator. A subsequent patch which tests arch page table helpers needs such a method to allocate PUD_SIZE sized memory block. In the future such methods might have other use cases as well. So alloc_gigantic_page() has been split carving out actual memory allocation method and made available via new alloc_gigantic_page_order() which is wrapped under CONFIG_CONTIG_ALLOC. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Vlastimil Babka <redacted> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Thomas Gleixner <redacted> Cc: Mike Rapoport <redacted> Cc: Mike Kravetz <redacted> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Dan Williams <redacted> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mark Brown <broonie@kernel.org> Cc: Steven Price <Steven.Price@arm.com> Cc: Ard Biesheuvel <redacted> Cc: Masahiro Yamada <redacted> Cc: Kees Cook <redacted> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Matthew Wilcox <willy@infradead.org> Cc: Sri Krishna chowdary <redacted> Cc: Dave Hansen <redacted> Cc: Russell King - ARM Linux <linux@armlinux.org.uk> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <redacted> Cc: Martin Schwidefsky <redacted> Cc: Heiko Carstens <redacted> Cc: "David S. Miller" <davem@davemloft.net> Cc: Vineet Gupta <redacted> Cc: James Hogan <jhogan@kernel.org> Cc: Paul Burton <redacted> Cc: Ralf Baechle <redacted> Cc: Kirill A. Shutemov <redacted> Cc: Gerald Schaefer <redacted> Cc: Christophe Leroy <redacted> Cc: David Rientjes <rientjes@google.com> Cc: Andrea Arcangeli <redacted> Cc: Oscar Salvador <osalvador@suse.de> Cc: Mel Gorman <redacted> Cc: linux-snps-arc@lists.infradead.org Cc: linux-mips@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-ia64@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-s390@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: sparclinux@vger.kernel.org Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <redacted> --- include/linux/gfp.h | 3 ++ mm/hugetlb.c | 76 +---------------------------------- mm/page_alloc.c | 98 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 102 insertions(+), 75 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index fb07b503dc45..379ad23437d1 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h@@ -589,6 +589,9 @@ static inline bool pm_suspended_storage(void) /* The below functions must be run on a range from a single zone. */ extern int alloc_contig_range(unsigned long start, unsigned long end, unsigned migratetype, gfp_t gfp_mask); +extern struct page *alloc_gigantic_page_order(unsigned int order, + gfp_t gfp_mask, int nid, + nodemask_t *nodemask); #endif void free_contig_range(unsigned long pfn, unsigned int nr_pages);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 977f9a323a7a..d199556a4a2c 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c@@ -1023,86 +1023,12 @@ static void free_gigantic_page(struct page *page, unsigned int order) } #ifdef CONFIG_CONTIG_ALLOC -static int __alloc_gigantic_page(unsigned long start_pfn, - unsigned long nr_pages, gfp_t gfp_mask) -{ - unsigned long end_pfn = start_pfn + nr_pages; - return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE, - gfp_mask); -} - -static bool pfn_range_valid_gigantic(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; - - if (PageReserved(page)) - return false; - - if (page_count(page) > 0) - return false; - - if (PageHuge(page)) - return false; - } - - return true; -} - -static bool zone_spans_last_pfn(const struct zone *zone, - unsigned long start_pfn, unsigned long nr_pages) -{ - unsigned long last_pfn = start_pfn + nr_pages - 1; - return zone_spans_pfn(zone, last_pfn); -} - static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, int nid, nodemask_t *nodemask) { unsigned int order = huge_page_order(h); - unsigned long nr_pages = 1 << order; - unsigned long ret, pfn, flags; - struct zonelist *zonelist; - struct zone *zone; - struct zoneref *z; - - zonelist = node_zonelist(nid, gfp_mask); - for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nodemask) { - spin_lock_irqsave(&zone->lock, flags); - pfn = ALIGN(zone->zone_start_pfn, nr_pages); - while (zone_spans_last_pfn(zone, pfn, nr_pages)) { - if (pfn_range_valid_gigantic(zone, pfn, nr_pages)) { - /* - * We release the zone lock here because - * alloc_contig_range() will also lock the zone - * at some point. If there's an allocation - * spinning on this lock, it may win the race - * and cause alloc_contig_range() to fail... - */ - spin_unlock_irqrestore(&zone->lock, flags); - ret = __alloc_gigantic_page(pfn, nr_pages, gfp_mask); - if (!ret) - return pfn_to_page(pfn); - spin_lock_irqsave(&zone->lock, flags); - } - pfn += nr_pages; - } - - spin_unlock_irqrestore(&zone->lock, flags); - } - - return NULL; + return alloc_gigantic_page_order(order, gfp_mask, nid, nodemask); } static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6ab8eb670fd3..0f67367213c6 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c@@ -8497,6 +8497,104 @@ int alloc_contig_range(unsigned long start, unsigned long end, pfn_max_align_up(end), migratetype); return ret; } + +static int __alloc_gigantic_page(unsigned long start_pfn, + unsigned long nr_pages, gfp_t gfp_mask) +{ + unsigned long end_pfn = start_pfn + nr_pages; + + return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE, + gfp_mask); +} + +static bool pfn_range_valid_gigantic(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; + + if (PageReserved(page)) + return false; + + if (page_count(page) > 0) + return false; + + if (PageHuge(page)) + return false; + } + return true; +} + +static bool zone_spans_last_pfn(const struct zone *zone, + unsigned long start_pfn, unsigned long nr_pages) +{ + unsigned long last_pfn = start_pfn + nr_pages - 1; + + return zone_spans_pfn(zone, last_pfn); +} + +/** + * alloc_gigantic_page_order() -- tries to allocate given order of pages + * @order: allocation order (greater than MAX_ORDER) + * @gfp_mask: GFP mask to use during compaction + * @nid: allocation node + * @nodemask: allocation nodemask + * + * This routine is an wrapper around alloc_contig_range() which scans over + * all zones on an applicable zonelist to find a contiguous pfn range which + * can the be allocated with alloc_contig_range(). This routine is intended + * to be used for allocations greater than MAX_ORDER. + * + * Return: page on success or NULL on failure. On success a memory block + * of 'order' starting with 'page' has been allocated successfully. Memory + * allocated here needs to be freed with free_contig_range(). + */ +struct page *alloc_gigantic_page_order(unsigned int order, gfp_t gfp_mask, + int nid, nodemask_t *nodemask) +{ + unsigned long nr_pages = 1 << order; + unsigned long ret, pfn, flags; + struct zonelist *zonelist; + struct zone *zone; + struct zoneref *z; + + zonelist = node_zonelist(nid, gfp_mask); + for_each_zone_zonelist_nodemask(zone, z, zonelist, + gfp_zone(gfp_mask), nodemask) { + spin_lock_irqsave(&zone->lock, flags); + + pfn = ALIGN(zone->zone_start_pfn, nr_pages); + while (zone_spans_last_pfn(zone, pfn, nr_pages)) { + if (pfn_range_valid_gigantic(zone, pfn, nr_pages)) { + /* + * We release the zone lock here because + * alloc_contig_range() will also lock the zone + * at some point. If there's an allocation + * spinning on this lock, it may win the race + * and cause alloc_contig_range() to fail... + */ + spin_unlock_irqrestore(&zone->lock, flags); + ret = __alloc_gigantic_page(pfn, nr_pages, + gfp_mask); + if (!ret) + return pfn_to_page(pfn); + spin_lock_irqsave(&zone->lock, flags); + } + pfn += nr_pages; + } + spin_unlock_irqrestore(&zone->lock, flags); + } + return NULL; +} #endif /* CONFIG_CONTIG_ALLOC */ void free_contig_range(unsigned long pfn, unsigned int nr_pages)
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2.20.1