From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f71.google.com (mail-pa0-f71.google.com [209.85.220.71]) by kanga.kvack.org (Postfix) with ESMTP id 5E1F86B02B2 for ; Wed, 2 Nov 2016 13:17:06 -0400 (EDT) Received: by mail-pa0-f71.google.com with SMTP id yt9so9823818pac.0 for ; Wed, 02 Nov 2016 10:17:06 -0700 (PDT) Received: from mga06.intel.com (mga06.intel.com. [134.134.136.31]) by mx.google.com with ESMTPS id u1si4149012pge.150.2016.11.02.10.17.05 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Nov 2016 10:17:05 -0700 (PDT) Subject: [mm PATCH v2 24/26] mm: Add support for releasing multiple instances of a page From: Alexander Duyck Date: Wed, 02 Nov 2016 07:16:08 -0400 Message-ID: <20161102111605.79519.37675.stgit@ahduyck-blue-test.jf.intel.com> In-Reply-To: <20161102111031.79519.14741.stgit@ahduyck-blue-test.jf.intel.com> References: <20161102111031.79519.14741.stgit@ahduyck-blue-test.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org This patch adds a function that allows us to batch free a page that has multiple references outstanding. Specifically this function can be used to drop a page being used in the page frag alloc cache. With this drivers can make use of functionality similar to the page frag alloc cache without having to do any workarounds for the fact that there is no function that frees multiple references. Signed-off-by: Alexander Duyck --- include/linux/gfp.h | 2 ++ mm/page_alloc.c | 14 ++++++++++++++ 2 files changed, 16 insertions(+) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index f8041f9de..4175dca 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -506,6 +506,8 @@ extern struct page *alloc_pages_vma(gfp_t gfp_mask, int order, extern void free_hot_cold_page_list(struct list_head *list, bool cold); struct page_frag_cache; +extern void __page_frag_drain(struct page *page, unsigned int order, + unsigned int count); extern void *__alloc_page_frag(struct page_frag_cache *nc, unsigned int fragsz, gfp_t gfp_mask); extern void __free_page_frag(void *addr); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 65e0b51..bb6d7bd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3938,6 +3938,20 @@ static struct page *__page_frag_refill(struct page_frag_cache *nc, return page; } +void __page_frag_drain(struct page *page, unsigned int order, + unsigned int count) +{ + VM_BUG_ON_PAGE(page_ref_count(page) == 0, page); + + if (page_ref_sub_and_test(page, count)) { + if (order == 0) + free_hot_cold_page(page, false); + else + __free_pages_ok(page, order); + } +} +EXPORT_SYMBOL(__page_frag_drain); + void *__alloc_page_frag(struct page_frag_cache *nc, unsigned int fragsz, gfp_t gfp_mask) { -- 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