From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f175.google.com (mail-pd0-f175.google.com [209.85.192.175]) by kanga.kvack.org (Postfix) with ESMTP id 94A226B009A for ; Tue, 3 Dec 2013 19:10:20 -0500 (EST) Received: by mail-pd0-f175.google.com with SMTP id w10so21005279pde.6 for ; Tue, 03 Dec 2013 16:10:20 -0800 (PST) Received: from LGEMRELSE1Q.lge.com (LGEMRELSE1Q.lge.com. [156.147.1.111]) by mx.google.com with ESMTP id f4si24646103pbm.115.2013.12.03.16.10.18 for ; Tue, 03 Dec 2013 16:10:19 -0800 (PST) From: Joonsoo Kim Subject: [PATCH v2 3/9] mm/rmap: factor lock function out of rmap_walk_anon() Date: Wed, 4 Dec 2013 09:12:14 +0900 Message-Id: <1386115940-21425-4-git-send-email-iamjoonsoo.kim@lge.com> In-Reply-To: <1386115940-21425-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1386115940-21425-1-git-send-email-iamjoonsoo.kim@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Mel Gorman , Hugh Dickins , Rik van Riel , Ingo Molnar , Naoya Horiguchi , Hillf Danton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Joonsoo Kim , Joonsoo Kim When we traverse anon_vma, we need to take a read-side anon_lock. But there is subtle difference in the situation so that we can't use same method to take a lock in each cases. Therefore, we need to make rmap_walk_anon() taking difference lock function. This patch is the first step, factoring lock function for anon_lock out of rmap_walk_anon(). It will be used in case of removing migration entry and in default of rmap_walk_anon(). Reviewed-by: Naoya Horiguchi Signed-off-by: Joonsoo Kim diff --git a/mm/rmap.c b/mm/rmap.c index a387c44..91c73c4 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1680,6 +1680,24 @@ void __put_anon_vma(struct anon_vma *anon_vma) } #ifdef CONFIG_MIGRATION +static struct anon_vma *rmap_walk_anon_lock(struct page *page) +{ + struct anon_vma *anon_vma; + + /* + * Note: remove_migration_ptes() cannot use page_lock_anon_vma_read() + * because that depends on page_mapped(); but not all its usages + * are holding mmap_sem. Users without mmap_sem are required to + * take a reference count to prevent the anon_vma disappearing + */ + anon_vma = page_anon_vma(page); + if (!anon_vma) + return NULL; + + anon_vma_lock_read(anon_vma); + return anon_vma; +} + /* * rmap_walk() and its helpers rmap_walk_anon() and rmap_walk_file(): * Called by migrate.c to remove migration ptes, but might be used more later. @@ -1692,16 +1710,10 @@ static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *, struct anon_vma_chain *avc; int ret = SWAP_AGAIN; - /* - * Note: remove_migration_ptes() cannot use page_lock_anon_vma_read() - * because that depends on page_mapped(); but not all its usages - * are holding mmap_sem. Users without mmap_sem are required to - * take a reference count to prevent the anon_vma disappearing - */ - anon_vma = page_anon_vma(page); + anon_vma = rmap_walk_anon_lock(page); if (!anon_vma) return ret; - anon_vma_lock_read(anon_vma); + anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { struct vm_area_struct *vma = avc->vma; unsigned long address = vma_address(page, vma); -- 1.7.9.5 -- 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