From: David Vrabel Date: Thu, 26 Apr 2012 18:44:06 +0000 (+0100) Subject: xen: correctly check for pending events when restoring irq flags X-Git-Tag: v3.4-rc5~11^2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7eb7ce4d2e8991aff4ecb71a81949a907ca755ac;p=pandora-kernel.git xen: correctly check for pending events when restoring irq flags In xen_restore_fl_direct(), xen_force_evtchn_callback() was being called even if no events were pending. This resulted in (depending on workload) about a 100 times as many xen_version hypercalls as necessary. Fix this by correcting the sense of the conditional jump. This seems to give a significant performance benefit for some workloads. There is some subtle tricksy "..since the check here is trying to check both pending and masked in a single cmpw, but I think this is correct. It will call check_events now only when the combined mask+pending word is 0x0001 (aka unmasked, pending)." (Ian) CC: stable@kernel.org Acked-by: Ian Campbell Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk --- Reading git-diff-tree failed