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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: David Howells , Al Viro , Christoph Hellwig , Jens Axboe , Jeff Layton , Christian Brauner , Chuck Lever III , Linus Torvalds , netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Bernard Metzler , Tom Talpey , linux-rdma@vger.kernel.org Subject: [RFC PATCH v2 05/48] mm: Move the page fragment allocator from page_alloc.c into its own file Date: Wed, 29 Mar 2023 15:13:11 +0100 Message-Id: <20230329141354.516864-6-dhowells@redhat.com> In-Reply-To: <20230329141354.516864-1-dhowells@redhat.com> References: <20230329141354.516864-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 1FFD210001F X-Stat-Signature: pmaaq5t6jfpx3uc1qnaxwdhbsjkidon3 X-HE-Tag: 1680099260-115710 X-HE-Meta: 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 GNPq/fCu 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Move the page fragment allocator from page_alloc.c into its own file preparatory to changing it. Signed-off-by: David Howells cc: Bernard Metzler cc: Tom Talpey cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Matthew Wilcox cc: linux-rdma@vger.kernel.org cc: netdev@vger.kernel.org --- mm/Makefile | 2 +- mm/page_alloc.c | 126 ----------------------------------------- mm/page_frag_alloc.c | 131 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 132 insertions(+), 127 deletions(-) create mode 100644 mm/page_frag_alloc.c diff --git a/mm/Makefile b/mm/Makefile index 8e105e5b3e29..4e6dc12b4cbd 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -52,7 +52,7 @@ obj-y := filemap.o mempool.o oom_kill.o fadvise.o \ readahead.o swap.o truncate.o vmscan.o shmem.o \ util.o mmzone.o vmstat.o backing-dev.o \ mm_init.o percpu.o slab_common.o \ - compaction.o \ + compaction.o page_frag_alloc.o \ interval_tree.o list_lru.o workingset.o \ debug.o gup.o mmap_lock.o $(mmu-y) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ac1fc986af44..c08847308907 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5694,132 +5694,6 @@ void free_pages(unsigned long addr, unsigned int order) EXPORT_SYMBOL(free_pages); -/* - * Page Fragment: - * An arbitrary-length arbitrary-offset area of memory which resides - * within a 0 or higher order page. Multiple fragments within that page - * are individually refcounted, in the page's reference counter. - * - * The page_frag functions below provide a simple allocation framework for - * page fragments. This is used by the network stack and network device - * drivers to provide a backing region of memory for use as either an - * sk_buff->head, or to be used in the "frags" portion of skb_shared_info. - */ -static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, - gfp_t gfp_mask) -{ - struct page *page = NULL; - gfp_t gfp = gfp_mask; - -#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) - gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY | - __GFP_NOMEMALLOC; - page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, - PAGE_FRAG_CACHE_MAX_ORDER); - nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE; -#endif - if (unlikely(!page)) - page = alloc_pages_node(NUMA_NO_NODE, gfp, 0); - - nc->va = page ? page_address(page) : NULL; - - return page; -} - -void __page_frag_cache_drain(struct page *page, unsigned int count) -{ - VM_BUG_ON_PAGE(page_ref_count(page) == 0, page); - - if (page_ref_sub_and_test(page, count)) - free_the_page(page, compound_order(page)); -} -EXPORT_SYMBOL(__page_frag_cache_drain); - -void *page_frag_alloc_align(struct page_frag_cache *nc, - unsigned int fragsz, gfp_t gfp_mask, - unsigned int align_mask) -{ - unsigned int size = PAGE_SIZE; - struct page *page; - int offset; - - if (unlikely(!nc->va)) { -refill: - page = __page_frag_cache_refill(nc, gfp_mask); - if (!page) - return NULL; - -#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) - /* if size can vary use size else just use PAGE_SIZE */ - size = nc->size; -#endif - /* Even if we own the page, we do not use atomic_set(). - * This would break get_page_unless_zero() users. - */ - page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE); - - /* reset page count bias and offset to start of new frag */ - nc->pfmemalloc = page_is_pfmemalloc(page); - nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; - nc->offset = size; - } - - offset = nc->offset - fragsz; - if (unlikely(offset < 0)) { - page = virt_to_page(nc->va); - - if (!page_ref_sub_and_test(page, nc->pagecnt_bias)) - goto refill; - - if (unlikely(nc->pfmemalloc)) { - free_the_page(page, compound_order(page)); - goto refill; - } - -#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) - /* if size can vary use size else just use PAGE_SIZE */ - size = nc->size; -#endif - /* OK, page count is 0, we can safely set it */ - set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1); - - /* reset page count bias and offset to start of new frag */ - nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; - offset = size - fragsz; - if (unlikely(offset < 0)) { - /* - * The caller is trying to allocate a fragment - * with fragsz > PAGE_SIZE but the cache isn't big - * enough to satisfy the request, this may - * happen in low memory conditions. - * We don't release the cache page because - * it could make memory pressure worse - * so we simply return NULL here. - */ - return NULL; - } - } - - nc->pagecnt_bias--; - offset &= align_mask; - nc->offset = offset; - - return nc->va + offset; -} -EXPORT_SYMBOL(page_frag_alloc_align); - -/* - * Frees a page fragment allocated out of either a compound or order 0 page. - */ -void page_frag_free(void *addr) -{ - struct page *page = virt_to_head_page(addr); - - if (unlikely(put_page_testzero(page))) - free_the_page(page, compound_order(page)); -} -EXPORT_SYMBOL(page_frag_free); - static void *make_alloc_exact(unsigned long addr, unsigned int order, size_t size) { diff --git a/mm/page_frag_alloc.c b/mm/page_frag_alloc.c new file mode 100644 index 000000000000..bee95824ef8f --- /dev/null +++ b/mm/page_frag_alloc.c @@ -0,0 +1,131 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Page fragment allocator + * + * Page Fragment: + * An arbitrary-length arbitrary-offset area of memory which resides within a + * 0 or higher order page. Multiple fragments within that page are + * individually refcounted, in the page's reference counter. + * + * The page_frag functions provide a simple allocation framework for page + * fragments. This is used by the network stack and network device drivers to + * provide a backing region of memory for use as either an sk_buff->head, or to + * be used in the "frags" portion of skb_shared_info. + */ + +#include +#include +#include + +static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, + gfp_t gfp_mask) +{ + struct page *page = NULL; + gfp_t gfp = gfp_mask; + +#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) + gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY | + __GFP_NOMEMALLOC; + page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, + PAGE_FRAG_CACHE_MAX_ORDER); + nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE; +#endif + if (unlikely(!page)) + page = alloc_pages_node(NUMA_NO_NODE, gfp, 0); + + nc->va = page ? page_address(page) : NULL; + + return page; +} + +void __page_frag_cache_drain(struct page *page, unsigned int count) +{ + VM_BUG_ON_PAGE(page_ref_count(page) == 0, page); + + if (page_ref_sub_and_test(page, count - 1)) + __free_pages(page, compound_order(page)); +} +EXPORT_SYMBOL(__page_frag_cache_drain); + +void *page_frag_alloc_align(struct page_frag_cache *nc, + unsigned int fragsz, gfp_t gfp_mask, + unsigned int align_mask) +{ + unsigned int size = PAGE_SIZE; + struct page *page; + int offset; + + if (unlikely(!nc->va)) { +refill: + page = __page_frag_cache_refill(nc, gfp_mask); + if (!page) + return NULL; + +#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) + /* if size can vary use size else just use PAGE_SIZE */ + size = nc->size; +#endif + /* Even if we own the page, we do not use atomic_set(). + * This would break get_page_unless_zero() users. + */ + page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE); + + /* reset page count bias and offset to start of new frag */ + nc->pfmemalloc = page_is_pfmemalloc(page); + nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; + nc->offset = size; + } + + offset = nc->offset - fragsz; + if (unlikely(offset < 0)) { + page = virt_to_page(nc->va); + + if (page_ref_count(page) != nc->pagecnt_bias) + goto refill; + if (unlikely(nc->pfmemalloc)) { + page_ref_sub(page, nc->pagecnt_bias - 1); + __free_pages(page, compound_order(page)); + goto refill; + } + +#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) + /* if size can vary use size else just use PAGE_SIZE */ + size = nc->size; +#endif + /* OK, page count is 0, we can safely set it */ + set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1); + + /* reset page count bias and offset to start of new frag */ + nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; + offset = size - fragsz; + if (unlikely(offset < 0)) { + /* + * The caller is trying to allocate a fragment + * with fragsz > PAGE_SIZE but the cache isn't big + * enough to satisfy the request, this may + * happen in low memory conditions. + * We don't release the cache page because + * it could make memory pressure worse + * so we simply return NULL here. + */ + return NULL; + } + } + + nc->pagecnt_bias--; + offset &= align_mask; + nc->offset = offset; + + return nc->va + offset; +} +EXPORT_SYMBOL(page_frag_alloc_align); + +/* + * Frees a page fragment allocated out of either a compound or order 0 page. + */ +void page_frag_free(void *addr) +{ + struct page *page = virt_to_head_page(addr); + + __free_pages(page, compound_order(page)); +} +EXPORT_SYMBOL(page_frag_free);