From: Takuya Yoshikawa Date: Mon, 20 Aug 2012 09:35:39 +0000 (+0900) Subject: KVM: MMU: Fix mmu_shrink() so that it can free mmu pages as intended X-Git-Tag: v3.6-rc4~14^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=35f2d16bb9ace0fb2671b8232839944ad9057c6f;p=pandora-kernel.git KVM: MMU: Fix mmu_shrink() so that it can free mmu pages as intended Although the possible race described in commit 85b7059169e128c57a3a8a3e588fb89cb2031da1 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 1952639665e92481c34c34c3e2a71bf3e66ba362 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 Cc: Gleb Natapov Signed-off-by: Avi Kivity --- Reading git-diff-tree failed