Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755285Ab2E3Ojs (ORCPT ); Wed, 30 May 2012 10:39:48 -0400 Received: from e28smtp04.in.ibm.com ([122.248.162.4]:42218 "EHLO e28smtp04.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752048Ab2E3Ojo (ORCPT ); Wed, 30 May 2012 10:39:44 -0400 From: "Aneesh Kumar K.V" To: linux-mm@kvack.org, kamezawa.hiroyu@jp.fujitsu.com, dhillf@gmail.com, rientjes@google.com, mhocko@suse.cz, akpm@linux-foundation.org, hannes@cmpxchg.org Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, "Aneesh Kumar K.V" , Andrea Arcangeli Subject: [PATCH -V7 05/14] hugetlb: avoid taking i_mmap_mutex in unmap_single_vma() for hugetlb Date: Wed, 30 May 2012 20:08:50 +0530 Message-Id: <1338388739-22919-6-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.10 In-Reply-To: <1338388739-22919-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1338388739-22919-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> x-cbid: 12053014-5564-0000-0000-00000301B935 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2012 Lines: 54 From: "Aneesh Kumar K.V" i_mmap_mutex lock was added in unmap_single_vma by 502717f4e ("hugetlb: fix linked list corruption in unmap_hugepage_range()") but we don't use page->lru in unmap_hugepage_range any more. Also the lock was taken higher up in the stack in some code path. That would result in deadlock. unmap_mapping_range (i_mmap_mutex) -> unmap_mapping_range_tree -> unmap_mapping_range_vma -> zap_page_range_single -> unmap_single_vma -> unmap_hugepage_range (i_mmap_mutex) For shared pagetable support for huge pages, since pagetable pages are ref counted we don't need any lock during huge_pmd_unshare. We do take i_mmap_mutex in huge_pmd_share while walking the vma_prio_tree in mapping. (39dde65c9940c97f ("shared page table for hugetlb page")). Signed-off-by: Aneesh Kumar K.V Cc: KAMEZAWA Hiroyuki Cc: Hillf Danton Cc: Michal Hocko Cc: Andrea Arcangeli Cc: Johannes Weiner --- mm/memory.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 545e18a..f6bc04f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1326,11 +1326,8 @@ static void unmap_single_vma(struct mmu_gather *tlb, * Since no pte has actually been setup, it is * safe to do nothing in this case. */ - if (vma->vm_file) { - mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); + if (vma->vm_file) __unmap_hugepage_range(tlb, vma, start, end, NULL); - mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); - } } else unmap_page_range(tlb, vma, start, end, details); } -- 1.7.10 -- 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/