From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f178.google.com (mail-wi0-f178.google.com [209.85.212.178]) by kanga.kvack.org (Postfix) with ESMTP id 026826B0074 for ; Sun, 22 Feb 2015 08:42:42 -0500 (EST) Received: by mail-wi0-f178.google.com with SMTP id em10so11518436wid.5 for ; Sun, 22 Feb 2015 05:42:41 -0800 (PST) Received: from mellanox.co.il ([193.47.165.129]) by mx.google.com with ESMTP id r1si12611302wiz.11.2015.02.22.05.42.39 for ; Sun, 22 Feb 2015 05:42:40 -0800 (PST) From: Shachar Raindel Subject: [PATCH V5 2/4] mm: Refactor do_wp_page - rewrite the unlock flow Date: Sun, 22 Feb 2015 15:42:16 +0200 Message-Id: <1424612538-25889-3-git-send-email-raindel@mellanox.com> In-Reply-To: <1424612538-25889-1-git-send-email-raindel@mellanox.com> References: <1424612538-25889-1-git-send-email-raindel@mellanox.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: kirill.shutemov@linux.intel.com, mgorman@suse.de, riel@redhat.com, ak@linux.intel.com, matthew.r.wilcox@intel.com, dave.hansen@linux.intel.com, n-horiguchi@ah.jp.nec.com, akpm@linux-foundation.org, torvalds@linux-foundation.org, haggaie@mellanox.com, aarcange@redhat.com, pfeiner@google.com, hannes@cmpxchg.org, sagig@mellanox.com, walken@google.com, raindel@mellanox.com, Dave Hansen When do_wp_page is ending, in several cases it needs to unlock the pages and ptls it was accessing. Currently, this logic was "called" by using a goto jump. This makes following the control flow of the function harder. Readability was further hampered by the unlock case containing large amount of logic needed only in one of the 3 cases. Using goto for cleanup is generally allowed. However, moving the trivial unlocking flows to the relevant call sites allow deeper refactoring in the next patch. Signed-off-by: Shachar Raindel Acked-by: Linus Torvalds Acked-by: Kirill A. Shutemov Acked-by: Rik van Riel Acked-by: Andi Kleen Acked-by: Haggai Eran Acked-by: Johannes Weiner Cc: Mel Gorman Cc: Matthew Wilcox Cc: Dave Hansen Cc: Naoya Horiguchi Cc: Andrew Morton Cc: Andrea Arcangeli Cc: Peter Feiner Cc: Michel Lespinasse --- mm/memory.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 7a04414..3afd9ce 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2066,7 +2066,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, { struct page *old_page, *new_page = NULL; pte_t entry; - int ret = 0; + int page_copied = 0; unsigned long mmun_start = 0; /* For mmu_notifiers */ unsigned long mmun_end = 0; /* For mmu_notifiers */ struct mem_cgroup *memcg; @@ -2101,7 +2101,9 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, &ptl); if (!pte_same(*page_table, orig_pte)) { unlock_page(old_page); - goto unlock; + pte_unmap_unlock(page_table, ptl); + page_cache_release(old_page); + return 0; } page_cache_release(old_page); } @@ -2148,7 +2150,9 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, &ptl); if (!pte_same(*page_table, orig_pte)) { unlock_page(old_page); - goto unlock; + pte_unmap_unlock(page_table, ptl); + page_cache_release(old_page); + return 0; } page_mkwrite = 1; } @@ -2246,29 +2250,28 @@ gotten: /* Free the old page.. */ new_page = old_page; - ret |= VM_FAULT_WRITE; + page_copied = 1; } else mem_cgroup_cancel_charge(new_page, memcg); if (new_page) page_cache_release(new_page); -unlock: + pte_unmap_unlock(page_table, ptl); - if (mmun_end > mmun_start) - mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); + mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); if (old_page) { /* * Don't let another task, with possibly unlocked vma, * keep the mlocked page. */ - if ((ret & VM_FAULT_WRITE) && (vma->vm_flags & VM_LOCKED)) { + if (page_copied && (vma->vm_flags & VM_LOCKED)) { lock_page(old_page); /* LRU manipulation */ munlock_vma_page(old_page); unlock_page(old_page); } page_cache_release(old_page); } - return ret; + return page_copied ? VM_FAULT_WRITE : 0; oom_free_new: page_cache_release(new_page); oom: -- 1.7.11.2 -- 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