From cd52e17ea8278f8449b6174a8e5ed439a2e44ffb Mon Sep 17 00:00:00 2001 From: Ian Campbell Date: Wed, 19 May 2010 16:19:25 +0100 Subject: [PATCH 1/2] xen: ensure timer tick is resumed even on CPU driving the resume The core suspend/resume code is run from stop_machine on CPU0 but parts of the suspend/resume machinery (including xen_arch_resume) are run on whichever CPU happened to schedule the xenwatch kernel thread. As part of the non-core resume code xen_arch_resume is called in order to restart the timer tick on non-boot processors. The boot processor itself is taken care of by core timekeeping code. xen_arch_resume uses smp_call_function which does not call the given function on the current processor. This means that we can end up with one CPU not receiving timer ticks if the xenwatch thread happened to be scheduled on CPU > 0. Use on_each_cpu instead of smp_call_function to ensure the timer tick is resumed everywhere. Signed-off-by: Ian Campbell Acked-by: Jeremy Fitzhardinge Cc: Stable Kernel # .32.x --- arch/x86/xen/suspend.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c index 987267f79bf5..a9c661108034 100644 --- a/arch/x86/xen/suspend.c +++ b/arch/x86/xen/suspend.c @@ -60,6 +60,6 @@ static void xen_vcpu_notify_restore(void *data) void xen_arch_resume(void) { - smp_call_function(xen_vcpu_notify_restore, - (void *)CLOCK_EVT_NOTIFY_RESUME, 1); + on_each_cpu(xen_vcpu_notify_restore, + (void *)CLOCK_EVT_NOTIFY_RESUME, 1); } From b3831cb55d383e8eb55d3b56c715fb48459b87c9 Mon Sep 17 00:00:00 2001 From: Ian Campbell Date: Tue, 25 May 2010 10:45:35 +0100 Subject: [PATCH 2/2] xen: avoid allocation causing potential swap activity on the resume path Since the device we are resuming could be the device containing the swap device we should ensure that the allocation cannot cause IO. On resume, this path is triggered when the running system tries to continue using its devices. If it cannot then the resume will fail; to try to avoid this we let it dip into the emergency pools. The majority of these changes were made when linux-2.6.18-xen.hg changeset e8b49cfbdac0 was ported upstream in a144ff09bc52ef3f3684ed23eadc9c7c0e57b3aa but somehow this hunk was dropped. Signed-off-by: Ian Campbell Acked-by: Jeremy Fitzhardinge Cc: Stable Kernel # .32.x --- drivers/xen/xenbus/xenbus_xs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c index eab33f1dbdf7..7b547f53f65e 100644 --- a/drivers/xen/xenbus/xenbus_xs.c +++ b/drivers/xen/xenbus/xenbus_xs.c @@ -499,7 +499,7 @@ int xenbus_printf(struct xenbus_transaction t, #define PRINTF_BUFFER_SIZE 4096 char *printf_buffer; - printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL); + printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_NOIO | __GFP_HIGH); if (printf_buffer == NULL) return -ENOMEM;