linux/arch
Takuya Yoshikawa 35f2d16bb9 KVM: MMU: Fix mmu_shrink() so that it can free mmu pages as intended
Although the possible race described in

  commit 85b7059169
  KVM: MMU: fix shrinking page from the empty mmu

was correct, the real cause of that issue was a more trivial bug of
mmu_shrink() introduced by

  commit 1952639665
  KVM: MMU: do not iterate over all VMs in mmu_shrink()

Here is the bug:

	if (kvm->arch.n_used_mmu_pages > 0) {
		if (!nr_to_scan--)
			break;
		continue;
	}

We skip VMs whose n_used_mmu_pages is not zero and try to shrink others:
in other words we try to shrink empty ones by mistake.

This patch reverses the logic so that mmu_shrink() can free pages from
the first VM whose n_used_mmu_pages is not zero.  Note that we also add
comments explaining the role of nr_to_scan which is not practically
important now, hoping this will be improved in the future.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-08-22 15:27:13 +03:00
..
alpha ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION 2012-07-30 17:25:21 -07:00
arm ARM: arm-soc Marvell Orion device-tree updates 2012-08-02 11:50:24 -07:00
avr32 ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION 2012-07-30 17:25:21 -07:00
blackfin Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k 2012-08-03 10:52:41 -07:00
c6x Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2012-07-24 10:01:50 -07:00
cris ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION 2012-07-30 17:25:21 -07:00
frv Merge branch 'akpm' (Andrew's patch-bomb) 2012-07-30 17:25:34 -07:00
h8300 ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION 2012-07-30 17:25:21 -07:00
hexagon Merge branch 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2012-07-30 11:24:53 -07:00
ia64 ACPI: Only count valid srat memory structures 2012-08-03 00:15:53 -04:00
m32r ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION 2012-07-30 17:25:21 -07:00
m68k Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k 2012-08-03 10:52:41 -07:00
microblaze Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k 2012-08-03 10:52:41 -07:00
mips Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2012-08-01 16:47:15 -07:00
mn10300 Merge branch 'akpm' (Andrew's patch-bomb) 2012-07-30 17:25:34 -07:00
openrisc Remove useless wrappers of asm-generic/rmap.h 2012-06-28 11:29:26 +02:00
parisc PCI changes for the 3.6 merge window: 2012-07-24 16:17:07 -07:00
powerpc ppc: e500_tlb memset clears nothing 2012-08-16 14:14:53 +02:00
s390 Merge branch 'akpm' (Andrew's patch-bomb) 2012-07-31 19:25:39 -07:00
score new helper: signal_delivered() 2012-06-01 12:58:52 -04:00
sh Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k 2012-08-03 10:52:41 -07:00
sparc This patch series contains a major revamp of how we collect entropy 2012-07-31 19:07:42 -07:00
tile memcg: rename config variables 2012-07-31 18:42:43 -07:00
um Merge branch 'for-linus-3.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml 2012-08-01 16:45:02 -07:00
unicore32 PCI changes for the 3.6 merge window: 2012-07-24 16:17:07 -07:00
x86 KVM: MMU: Fix mmu_shrink() so that it can free mmu pages as intended 2012-08-22 15:27:13 +03:00
xtensa xtensa: select generic atomic64_t support 2012-07-31 18:42:39 -07:00
.gitignore
Kconfig ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION 2012-07-30 17:25:21 -07:00