Messages in this thread Patch in this message | | | Date | Mon, 28 Mar 2016 16:15:49 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v2] mm/vmap: Add a notifier for when we run out of vmap address space |
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On Thu, 17 Mar 2016 13:41:56 +0000 Chris Wilson <chris@chris-wilson.co.uk> wrote:
> On Thu, Mar 17, 2016 at 01:34:59PM +0000, Chris Wilson wrote: > > vmaps are temporary kernel mappings that may be of long duration. > > Reusing a vmap on an object is preferrable for a driver as the cost of > > setting up the vmap can otherwise dominate the operation on the object. > > However, the vmap address space is rather limited on 32bit systems and > > so we add a notification for vmap pressure in order for the driver to > > release any cached vmappings. > > > > The interface is styled after the oom-notifier where the callees are > > passed a pointer to an unsigned long counter for them to indicate if they > > have freed any space. > > > > v2: Guard the blocking notifier call with gfpflags_allow_blocking() > > > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> > > Cc: Andrew Morton <akpm@linux-foundation.org> > > Cc: David Rientjes <rientjes@google.com> > > Cc: Roman Peniaev <r.peniaev@gmail.com> > > Cc: Mel Gorman <mgorman@techsingularity.net> > > Cc: linux-mm@kvack.org > > Cc: linux-kernel@vger.kernel.org > > --- > > include/linux/vmalloc.h | 4 ++++ > > mm/vmalloc.c | 27 +++++++++++++++++++++++++++ > > 2 files changed, 31 insertions(+) > > > > diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h > > index d1f1d338af20..edd676b8e112 100644 > > --- a/include/linux/vmalloc.h > > +++ b/include/linux/vmalloc.h > > @@ -187,4 +187,8 @@ pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms) > > #define VMALLOC_TOTAL 0UL > > #endif > > > > +struct notitifer_block; > Omg. /o\
Hah.
Please move the forward declaration to top-of-file. This prevents people from later adding the same thing at line 100 - this has happened before.
Apart from that, all looks OK to me - please merge it via the DRM tree if that is more convenient.
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