From be404f0212ffa8f67361f8ee460a25d901d88991 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 8 Oct 2009 22:47:30 +0200 Subject: [PATCH] PM / freezer: Don't get over-anxious while waiting Freezing isn't exactly the most latency sensitive operation and there's no reason to burn cpu cycles and power waiting for it to complete. msleep(10) instead of yield(). This should improve reliability of emergency hibernation. [rjw: Modified the comment next to the msleep(10).] Signed-off-by: Tejun Heo Signed-off-by: Rafael J. Wysocki --- kernel/power/process.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/kernel/power/process.c b/kernel/power/process.c index cc2e55373b6..5ade1bdcf36 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -14,6 +14,7 @@ #include #include #include +#include /* * Timeout for stopping processes @@ -41,7 +42,7 @@ static int try_to_freeze_tasks(bool sig_only) do_gettimeofday(&start); end_time = jiffies + TIMEOUT; - do { + while (true) { todo = 0; read_lock(&tasklist_lock); do_each_thread(g, p) { @@ -62,10 +63,15 @@ static int try_to_freeze_tasks(bool sig_only) todo++; } while_each_thread(g, p); read_unlock(&tasklist_lock); - yield(); /* Yield is okay here */ - if (time_after(jiffies, end_time)) + if (!todo || time_after(jiffies, end_time)) break; - } while (todo); + + /* + * We need to retry, but first give the freezing tasks some + * time to enter the regrigerator. + */ + msleep(10); + } do_gettimeofday(&end); elapsed_csecs64 = timeval_to_ns(&end) - timeval_to_ns(&start);