Patchwork [16/18] kvm: Do not use qemu_fair_mutex

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Submitter Jan Kiszka
Date Jan. 21, 2011, 8:48 p.m.
Message ID <b736a04734650639499bb3244003cfc7627e94b0.1295642900.git.jan.kiszka@web.de>
Download mbox | patch
Permalink /patch/79939/
State New
Headers show

Comments

Jan Kiszka - Jan. 21, 2011, 8:48 p.m.
From: Jan Kiszka <jan.kiszka@siemens.com>

The imbalance in the hold time of qemu_global_mutex only exists in TCG
mode. In contrast to TCG VCPUs, KVM drops the global lock during guest
execution. We already avoid touching the fairness lock from the
IO-thread in KVM mode, so also stop using it from the VCPU threads.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 cpus.c |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

Patch

diff --git a/cpus.c b/cpus.c
index 0309189..4c9928e 100644
--- a/cpus.c
+++ b/cpus.c
@@ -735,9 +735,7 @@  static sigset_t block_io_signals(void)
 void qemu_mutex_lock_iothread(void)
 {
     if (kvm_enabled()) {
-        qemu_mutex_lock(&qemu_fair_mutex);
         qemu_mutex_lock(&qemu_global_mutex);
-        qemu_mutex_unlock(&qemu_fair_mutex);
     } else {
         qemu_mutex_lock(&qemu_fair_mutex);
         if (qemu_mutex_trylock(&qemu_global_mutex)) {