From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Aneesh Kumar K.V" Subject: [PATCH -V6 05/14] hugetlb: Avoid taking i_mmap_mutex in unmap_single_vma for hugetlb Date: Mon, 16 Apr 2012 16:14:42 +0530 Message-ID: <1334573091-18602-6-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1334573091-18602-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Return-path: In-Reply-To: <1334573091-18602-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-mm@kvack.org, mgorman@suse.de, kamezawa.hiroyu@jp.fujitsu.com, dhillf@gmail.com, aarcange@redhat.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" From: "Aneesh Kumar K.V" i_mmap_mutex lock was added in unmap_single_vma by 502717f4e112b18d9c37753a32f675bec9f2838b 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. ( 39dde65c9940c97fcd178a3d2b1c57ed8b7b68aa ) Signed-off-by: Aneesh Kumar K.V --- mm/memory.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 4b11961..d642b3e 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, 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org