Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932526AbaJXWHk (ORCPT ); Fri, 24 Oct 2014 18:07:40 -0400 Received: from homie.mail.dreamhost.com ([208.97.132.208]:39241 "EHLO homiemail-a38.g.dreamhost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756040AbaJXWGw (ORCPT ); Fri, 24 Oct 2014 18:06:52 -0400 From: Davidlohr Bueso To: akpm@linux-foundation.org Cc: hughd@google.com, riel@redhat.com, mgorman@suse.de, peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org, dbueso@suse.de, linux-mm@kvack.org, Davidlohr Bueso Subject: [PATCH 08/10] mm/mremap: share the i_mmap_rwsem Date: Fri, 24 Oct 2014 15:06:18 -0700 Message-Id: <1414188380-17376-9-git-send-email-dave@stgolabs.net> X-Mailer: git-send-email 1.8.4.5 In-Reply-To: <1414188380-17376-1-git-send-email-dave@stgolabs.net> References: <1414188380-17376-1-git-send-email-dave@stgolabs.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As per the comment in move_ptes(), we only require taking the anon vma and i_mmap locks to ensure that rmap will always observe either the old or new ptes, in the case of need_rmap_lock=true. No modifications to the tree itself, thus share the i_mmap_rwsem. Signed-off-by: Davidlohr Bueso --- XXX: the same *should* apply for the anon vma, as there are no modifications to the chain. mm/mremap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/mremap.c b/mm/mremap.c index 84aa36f..a34500c 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -119,7 +119,7 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd, if (need_rmap_locks) { if (vma->vm_file) { mapping = vma->vm_file->f_mapping; - i_mmap_lock_write(mapping); + i_mmap_lock_read(mapping); } if (vma->anon_vma) { anon_vma = vma->anon_vma; @@ -156,7 +156,7 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd, if (anon_vma) anon_vma_unlock_write(anon_vma); if (mapping) - i_mmap_unlock_write(mapping); + i_mmap_unlock_read(mapping); } #define LATENCY_LIMIT (64 * PAGE_SIZE) -- 1.8.4.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/