Messages in this thread | | | Date | Wed, 29 Oct 2008 00:29:44 +0100 | From | Nick Piggin <> | Subject | Re: [PATCH] regression: vmalloc easily fail. |
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On Tue, Oct 28, 2008 at 08:55:13PM -0200, Glauber Costa wrote: > Commit db64fe02258f1507e13fe5212a989922323685ce broke > KVM (the symptom) for me. The cause is that vmalloc > allocations fail, despite of the fact that /proc/meminfo > shows plenty of vmalloc space available. > > After some investigation, it seems to me that the current > way to compute the next addr in the rb-tree transversal > leaves a spare page between each allocation. After a few > allocations, regardless of their size, we run out of vmalloc > space.
Right... that was to add a guard page like the old vmalloc allocator. vmallocs still add their extra page too, so most of them will have a 2 page guard area, but I didn't think this would hurt significantly.
I'm not against the patch, but I wonder exactly what is filling it up and how? (can you look at the vmalloc proc function to find out?)
> > Signed-off-by: Glauber Costa <glommer@redhat.com> > Cc: Jeremy Fitzhardinge <jeremy@goop.org> > Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> > --- > mm/vmalloc.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 0365369..a33b0d1 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -363,7 +363,7 @@ retry: > } > > while (addr + size >= first->va_start && addr + size <= vend) { > - addr = ALIGN(first->va_end + PAGE_SIZE, align); > + addr = ALIGN(first->va_end, align); > > n = rb_next(&first->rb_node); > if (n) > -- > 1.5.6.5
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