From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-we0-f176.google.com (mail-we0-f176.google.com [74.125.82.176]) by kanga.kvack.org (Postfix) with ESMTP id 71EF06B007B for ; Sun, 22 Feb 2015 08:42:57 -0500 (EST) Received: by wevl61 with SMTP id l61so9300353wev.2 for ; Sun, 22 Feb 2015 05:42:57 -0800 (PST) Received: from mellanox.co.il ([193.47.165.129]) by mx.google.com with ESMTP id qq10si56480899wjc.197.2015.02.22.05.42.55 for ; Sun, 22 Feb 2015 05:42:56 -0800 (PST) From: Shachar Raindel Subject: [PATCH V5 4/4] mm: Refactor do_wp_page handling of shared vma into a function Date: Sun, 22 Feb 2015 15:42:18 +0200 Message-Id: <1424612538-25889-5-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 The do_wp_page function is extremely long. Extract the logic for handling a page belonging to a shared vma into a function of its own. This helps the readability of the code, without doing any functional change in it. 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 | 86 ++++++++++++++++++++++++++++++++++--------------------------- 1 file changed, 48 insertions(+), 38 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index a06e705..b246d22 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2181,6 +2181,52 @@ oom: return VM_FAULT_OOM; } +static int wp_page_shared(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long address, pte_t *page_table, + pmd_t *pmd, spinlock_t *ptl, pte_t orig_pte, + struct page *old_page) + __releases(ptl) +{ + int page_mkwrite = 0; + + page_cache_get(old_page); + + /* + * Only catch write-faults on shared writable pages, + * read-only shared pages can get COWed by + * get_user_pages(.write=1, .force=1). + */ + if (vma->vm_ops && vma->vm_ops->page_mkwrite) { + int tmp; + + pte_unmap_unlock(page_table, ptl); + tmp = do_page_mkwrite(vma, old_page, address); + if (unlikely(!tmp || (tmp & + (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { + page_cache_release(old_page); + return tmp; + } + /* + * Since we dropped the lock we need to revalidate + * the PTE as someone else may have changed it. If + * they did, we just return, as we can count on the + * MMU to tell us if they didn't also make it writable. + */ + page_table = pte_offset_map_lock(mm, pmd, address, + &ptl); + if (!pte_same(*page_table, orig_pte)) { + unlock_page(old_page); + pte_unmap_unlock(page_table, ptl); + page_cache_release(old_page); + return 0; + } + page_mkwrite = 1; + } + + return wp_page_reuse(mm, vma, address, page_table, ptl, + orig_pte, old_page, page_mkwrite, 1); +} + /* * This routine handles present pages, when users try to write * to a shared page. It is done by copying the page to a new address @@ -2259,44 +2305,8 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, unlock_page(old_page); } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == (VM_WRITE|VM_SHARED))) { - int page_mkwrite = 0; - - page_cache_get(old_page); - - /* - * Only catch write-faults on shared writable pages, - * read-only shared pages can get COWed by - * get_user_pages(.write=1, .force=1). - */ - if (vma->vm_ops && vma->vm_ops->page_mkwrite) { - int tmp; - - pte_unmap_unlock(page_table, ptl); - tmp = do_page_mkwrite(vma, old_page, address); - if (unlikely(!tmp || (tmp & - (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { - page_cache_release(old_page); - return tmp; - } - /* - * Since we dropped the lock we need to revalidate - * the PTE as someone else may have changed it. If - * they did, we just return, as we can count on the - * MMU to tell us if they didn't also make it writable. - */ - page_table = pte_offset_map_lock(mm, pmd, address, - &ptl); - if (!pte_same(*page_table, orig_pte)) { - unlock_page(old_page); - pte_unmap_unlock(page_table, ptl); - page_cache_release(old_page); - return 0; - } - page_mkwrite = 1; - } - - return wp_page_reuse(mm, vma, address, page_table, ptl, - orig_pte, old_page, page_mkwrite, 1); + return wp_page_shared(mm, vma, address, page_table, pmd, + ptl, orig_pte, old_page); } /* -- 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