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authorSuraj Jitindar Singh <sjitindarsingh@gmail.com>2016-10-14 02:53:21 +0200
committerPaul Mackerras <paulus@ozlabs.org>2016-11-28 01:48:47 +0100
commite03f3921e597cbcc6880033e5c52fa1db524f88b (patch)
tree70e344307fc50a2a9b477071debfcb9e013cf340 /arch/powerpc/kvm
parentKVM: PPC: Book3S HV: Use generic kvm module parameters (diff)
downloadlinux-e03f3921e597cbcc6880033e5c52fa1db524f88b.tar.xz
linux-e03f3921e597cbcc6880033e5c52fa1db524f88b.zip
KVM: PPC: Book3S HV: Add check for module parameter halt_poll_ns
The kvm module parameter halt_poll_ns defines the global maximum halt polling interval and can be dynamically changed by writing to the /sys/module/kvm/parameters/halt_poll_ns sysfs file. However in kvm-hv this module parameter value is only ever checked when we grow the current polling interval for the given vcore. This means that if we decrease the halt_poll_ns value below the current polling interval we won't see any effect unless we try to grow the polling interval above the new max at some point or it happens to be shrunk below the halt_poll_ns value. Update the halt polling code so that we always check for a new module param value of halt_poll_ns and set the current halt polling interval to it if it's currently greater than the new max. This means that it's redundant to also perform this check in the grow_halt_poll_ns() function now. Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch/powerpc/kvm')
-rw-r--r--arch/powerpc/kvm/book3s_hv.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index f0d22ced3e1f..0b0ca272a13c 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -2599,9 +2599,6 @@ static void grow_halt_poll_ns(struct kvmppc_vcore *vc)
vc->halt_poll_ns = 10000;
else
vc->halt_poll_ns *= halt_poll_ns_grow;
-
- if (vc->halt_poll_ns > halt_poll_ns)
- vc->halt_poll_ns = halt_poll_ns;
}
static void shrink_halt_poll_ns(struct kvmppc_vcore *vc)
@@ -2721,6 +2718,8 @@ out:
else if (vc->halt_poll_ns < halt_poll_ns &&
block_ns < halt_poll_ns)
grow_halt_poll_ns(vc);
+ if (vc->halt_poll_ns > halt_poll_ns)
+ vc->halt_poll_ns = halt_poll_ns;
} else
vc->halt_poll_ns = 0;