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author | Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> | 2013-06-19 13:09:21 +0400 |
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committer | Gleb Natapov <gleb@redhat.com> | 2013-06-27 15:20:43 +0400 |
commit | 0cbf8e437b60b8b12d97589509d3e5a581731d36 (patch) | |
tree | 9990c3958c06c8737d19f510f90ee453c2b14350 /Documentation | |
parent | accaefe07ddbeb12c0de4cec1d62dba6a0ea1605 (diff) | |
download | linux-0cbf8e437b60b8b12d97589509d3e5a581731d36.tar.xz |
KVM: MMU: document write_flooding_count
Document write_flooding_count to Documentation/virtual/kvm/mmu.txt
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/virtual/kvm/mmu.txt | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/mmu.txt b/Documentation/virtual/kvm/mmu.txt index f514a3fad9b9..0db7743c55e1 100644 --- a/Documentation/virtual/kvm/mmu.txt +++ b/Documentation/virtual/kvm/mmu.txt @@ -215,6 +215,15 @@ Shadow pages contain the following information: atomically. The reader uses this while running out of the MMU lock to detect in-progress updates and retry them until the writer has finished the write. + write_flooding_count: + A guest may write to a page table many times, causing a lot of + emulations if the page needs to be write-protected (see "Synchronized + and unsynchronized pages" below). Leaf pages can be unsynchronized + so that they do not trigger frequent emulation, but this is not + possible for non-leafs. This field counts the number of emulations + since the last time the page table was actually used; if emulation + is triggered too frequently on this page, KVM will unmap the page + to avoid emulation in the future. Reverse map =========== |