From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: David Rientjes <rientjes@google.com>
Cc: linux-mm@kvack.org, kamezawa.hiroyu@jp.fujitsu.com,
dhillf@gmail.com, mhocko@suse.cz, akpm@linux-foundation.org,
hannes@cmpxchg.org, linux-kernel@vger.kernel.org,
cgroups@vger.kernel.org, Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH -V7 05/14] hugetlb: avoid taking i_mmap_mutex in unmap_single_vma() for hugetlb
Date: Thu, 31 May 2012 10:55:40 +0530 [thread overview]
Message-ID: <20120531052540.GA24855@skywalker.linux.vnet.ibm.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1205301857170.25774@chino.kir.corp.google.com>
On Wed, May 30, 2012 at 06:57:47PM -0700, David Rientjes wrote:
> On Wed, 30 May 2012, Aneesh Kumar K.V wrote:
>
> > From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
> >
> > 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)
> >
>
> You should be able to show this with lockdep?
I was not able to get a lockdep report
>
> > 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")).
> >
>
> I think this should be folded into patch 4, the code you're removing here
> is just added in that function unnecessarily.
>
I am removing i_mmap_mutex in this patch. That is not added in patch 4.
-aneesh
next prev parent reply other threads:[~2012-05-31 5:26 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-30 14:38 [PATCH -V7 00/14] hugetlb: Add HugeTLB controller to control HugeTLB allocation Aneesh Kumar K.V
2012-05-30 14:38 ` [PATCH -V7 01/14] hugetlb: rename max_hstate to hugetlb_max_hstate Aneesh Kumar K.V
2012-05-31 0:48 ` Konrad Rzeszutek Wilk
2012-05-31 5:47 ` Aneesh Kumar K.V
2012-05-31 0:55 ` David Rientjes
2012-05-30 14:38 ` [PATCH -V7 02/14] hugetlbfs: don't use ERR_PTR with VM_FAULT* values Aneesh Kumar K.V
2012-05-31 0:54 ` Konrad Rzeszutek Wilk
2012-05-31 1:02 ` David Rientjes
2012-05-31 5:45 ` Aneesh Kumar K.V
2012-05-31 6:50 ` David Rientjes
2012-05-30 14:38 ` [PATCH -V7 03/14] hugetlbfs: add an inline helper for finding hstate index Aneesh Kumar K.V
2012-05-31 1:05 ` David Rientjes
2012-05-30 14:38 ` [PATCH -V7 04/14] hugetlb: use mmu_gather instead of a temporary linked list for accumulating pages Aneesh Kumar K.V
2012-05-31 1:56 ` David Rientjes
2012-05-31 5:35 ` Aneesh Kumar K.V
2012-05-30 14:38 ` [PATCH -V7 05/14] hugetlb: avoid taking i_mmap_mutex in unmap_single_vma() for hugetlb Aneesh Kumar K.V
2012-05-31 1:57 ` David Rientjes
2012-05-31 5:25 ` Aneesh Kumar K.V [this message]
2012-05-30 14:38 ` [PATCH -V7 06/14] hugetlb: simplify migrate_huge_page() Aneesh Kumar K.V
2012-05-30 14:38 ` [PATCH -V7 07/14] mm/page_cgroup: Make page_cgroup point to the cgroup rather than the mem_cgroup Aneesh Kumar K.V
2012-06-05 1:44 ` Kamezawa Hiroyuki
2012-06-05 2:53 ` Aneesh Kumar K.V
2012-06-05 3:40 ` Kamezawa Hiroyuki
2012-06-07 19:05 ` Aneesh Kumar K.V
2012-05-30 14:38 ` [PATCH -V7 08/14] hugetlbfs: add a list for tracking in-use HugeTLB pages Aneesh Kumar K.V
2012-05-30 14:38 ` [PATCH -V7 09/14] hugetlbfs: Make some static variables global Aneesh Kumar K.V
2012-05-30 14:38 ` [PATCH -V7 10/14] hugetlbfs: Add new HugeTLB cgroup Aneesh Kumar K.V
2012-05-31 1:19 ` Konrad Rzeszutek Wilk
2012-05-31 5:43 ` Aneesh Kumar K.V
2012-05-31 9:43 ` Michal Hocko
2012-05-31 14:01 ` Michal Hocko
2012-05-30 14:38 ` [PATCH -V7 11/14] hugetlbfs: add hugetlb cgroup control files Aneesh Kumar K.V
2012-05-31 1:32 ` Konrad Rzeszutek Wilk
2012-05-31 5:39 ` Aneesh Kumar K.V
2012-05-30 14:38 ` [PATCH -V7 12/14] hugetlb: add charge/uncharge calls for HugeTLB alloc/free Aneesh Kumar K.V
2012-05-30 14:38 ` [PATCH -V7 13/14] hugetlb: migrate hugetlb cgroup info from oldpage to new page during migration Aneesh Kumar K.V
2012-05-30 14:38 ` [PATCH -V7 14/14] hugetlb: add HugeTLB controller documentation Aneesh Kumar K.V
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