From: Rik van Riel <riel@redhat.com>
To: Michel Lespinasse <walken@google.com>
Cc: Andy Lutomirski <luto@amacapital.net>,
Ingo Molnar <mingo@kernel.org>, Al Viro <viro@zeniv.linux.org.uk>,
Hugh Dickins <hughd@google.com>, Jorn_Engel <joern@logfs.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/9] mm: remap_file_pages() fixes
Date: Wed, 02 Jan 2013 19:31:01 -0500 [thread overview]
Message-ID: <50E4D145.5030006@redhat.com> (raw)
In-Reply-To: <1356050997-2688-3-git-send-email-walken@google.com>
On 12/20/2012 07:49 PM, Michel Lespinasse wrote:
> Assorted small fixes. The first two are quite small:
>
> - Move check for vma->vm_private_data && !(vma->vm_flags & VM_NONLINEAR)
> within existing if (!(vma->vm_flags & VM_NONLINEAR)) block.
> Purely cosmetic.
>
> - In the VM_LOCKED case, when dropping PG_Mlocked for the over-mapped
> range, make sure we own the mmap_sem write lock around the
> munlock_vma_pages_range call as this manipulates the vma's vm_flags.
>
> Last fix requires a longer explanation. remap_file_pages() can do its work
> either through VM_NONLINEAR manipulation or by creating extra vmas.
> These two cases were inconsistent with each other (and ultimately, both wrong)
> as to exactly when did they fault in the newly mapped file pages:
>
> - In the VM_NONLINEAR case, new file pages would be populated if
> the MAP_NONBLOCK flag wasn't passed. If MAP_NONBLOCK was passed,
> new file pages wouldn't be populated even if the vma is already
> marked as VM_LOCKED.
>
> - In the linear (emulated) case, the work is passed to the mmap_region()
> function which would populate the pages if the vma is marked as
> VM_LOCKED, and would not otherwise - regardless of the value of the
> MAP_NONBLOCK flag, because MAP_POPULATE wasn't being passed to
> mmap_region().
>
> The desired behavior is that we want the pages to be populated and locked
> if the vma is marked as VM_LOCKED, or to be populated if the MAP_NONBLOCK
> flag is not passed to remap_file_pages().
>
> Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
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next prev parent reply other threads:[~2013-01-03 0:31 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-21 0:49 [PATCH 0/9] Avoid populating unbounded num of ptes with mmap_sem held Michel Lespinasse
2012-12-21 0:49 ` [PATCH 1/9] mm: make mlockall preserve flags other than VM_LOCKED in def_flags Michel Lespinasse
2012-12-22 4:25 ` Rik van Riel
2012-12-21 0:49 ` [PATCH 2/9] mm: remap_file_pages() fixes Michel Lespinasse
2013-01-03 0:31 ` Rik van Riel [this message]
2012-12-21 0:49 ` [PATCH 3/9] mm: introduce mm_populate() for populating new vmas Michel Lespinasse
2013-01-03 2:14 ` Rik van Riel
2012-12-21 0:49 ` [PATCH 4/9] mm: use mm_populate() for blocking remap_file_pages() Michel Lespinasse
2013-01-03 2:25 ` Rik van Riel
2013-03-10 18:55 ` Tommi Rantala
2013-03-11 23:03 ` Andrew Morton
2013-03-12 0:24 ` Michel Lespinasse
2013-03-12 4:23 ` Hillf Danton
2013-03-12 5:01 ` Michel Lespinasse
2013-03-12 20:47 ` Andrew Morton
2012-12-21 0:49 ` [PATCH 5/9] mm: use mm_populate() when adjusting brk with MCL_FUTURE in effect Michel Lespinasse
2013-01-03 2:56 ` Rik van Riel
2012-12-21 0:49 ` [PATCH 6/9] mm: use mm_populate() for mremap() of VM_LOCKED vmas Michel Lespinasse
2013-01-03 5:47 ` Rik van Riel
2012-12-21 0:49 ` [PATCH 7/9] mm: remove flags argument to mmap_region Michel Lespinasse
2013-01-03 5:49 ` Rik van Riel
2012-12-21 0:49 ` [PATCH 8/9] mm: directly use __mlock_vma_pages_range() in find_extend_vma() Michel Lespinasse
2013-01-03 5:50 ` Rik van Riel
2012-12-21 0:49 ` [PATCH 9/9] mm: introduce VM_POPULATE flag to better deal with racy userspace programs Michel Lespinasse
2013-01-03 6:20 ` Rik van Riel
2012-12-21 10:46 ` [PATCH 0/9] Avoid populating unbounded num of ptes with mmap_sem held Michel Lespinasse
2012-12-22 15:02 ` Greg Ungerer
2013-01-23 13:37 ` Greg Ungerer
2012-12-22 0:36 ` Andy Lutomirski
2012-12-22 0:59 ` Michel Lespinasse
2012-12-22 1:09 ` Andy Lutomirski
2012-12-22 1:59 ` Michel Lespinasse
2012-12-22 2:16 ` Andy Lutomirski
2012-12-22 9:37 ` Michel Lespinasse
2012-12-22 9:45 ` [PATCH 10/9] mm: make do_mmap_pgoff return populate as a size in bytes, not as a bool Michel Lespinasse
2013-01-03 6:21 ` Rik van Riel
2013-01-03 18:54 ` Andy Lutomirski
2013-01-03 18:56 ` [PATCH 0/9] Avoid populating unbounded num of ptes with mmap_sem held Andy Lutomirski
2013-01-04 18:16 ` Andy Lutomirski
2013-01-04 22:58 ` Michel Lespinasse
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