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From: Glauber Costa <glommer@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: kvm@vger.kernel.org, avi@redhat.com, aliguori@codemonkey.ws,
	npiggin@suse.de, Jeremy Fitzhardinge <jeremy@goop.org>,
	Krzysztof Helt <krzysztof.h1@poczta.fm>
Subject: [PATCH] regression: vmalloc easily fail.
Date: Tue, 28 Oct 2008 20:55:13 -0200	[thread overview]
Message-ID: <1225234513-3996-1-git-send-email-glommer@redhat.com> (raw)

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.

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


             reply	other threads:[~2008-10-28 20:58 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-28 22:55 Glauber Costa [this message]
2008-10-28 21:03 ` Avi Kivity
2008-10-28 21:09   ` Glauber Costa
2008-10-28 21:22     ` Matias Zabaljauregui
2008-10-28 21:22   ` Roland Dreier
2008-10-28 21:42     ` Arjan van de Ven
2008-10-28 22:03       ` Roland Dreier
2008-10-28 23:29 ` Nick Piggin
2008-10-29  6:28   ` Avi Kivity
2008-10-29  9:48   ` Glauber Costa
2008-10-29 10:11     ` Nick Piggin
2008-10-29 10:29       ` Avi Kivity
2008-10-29 10:43         ` Nick Piggin
2008-10-29 22:07           ` Glauber Costa
2008-10-30  1:53             ` Nick Piggin
2008-10-30  4:49             ` Nick Piggin
2008-10-30 11:28               ` Glauber Costa
2008-10-31  7:16                 ` Nick Piggin
2008-11-04 17:51                   ` Glauber Costa
2008-11-05  0:21                   ` Glauber Costa
2008-10-30 16:46               ` Matt Mackall
2008-10-30 18:04                 ` Glauber Costa
2008-10-31  2:59                   ` Nick Piggin
2008-11-07 20:37               ` Glauber Costa

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