Patchwork [v3,20/21] kvm: Do not use qemu_fair_mutex

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Submitter Jan Kiszka
Date Jan. 4, 2011, 8:32 a.m.
Message ID <f7af9e3f06b5a335b246da949a78ec18163b783f.1294129949.git.jan.kiszka@web.de>
Download mbox | patch
Permalink /patch/77426/
State New
Headers show

Comments

Jan Kiszka - Jan. 4, 2011, 8:32 a.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 2847dcf..db74530 100644
--- a/cpus.c
+++ b/cpus.c
@@ -740,9 +740,7 @@  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)) {