From 866e26115cba6b59cec669b6307599e3e4440491 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 20 Jul 2010 15:23:15 -0700 Subject: timers: Document meaning of deferrable timer Steal some text from 6e453a67510 "Add support for deferrable timers". A reader shouldn't have to dig through the git logs for the basic description of a deferrable timer. Signed-off-by: J. Bruce Fields Cc: johnstul@us.ibm.com Signed-off-by: Andrew Morton Signed-off-by: Thomas Gleixner --- kernel/timer.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'kernel/timer.c') diff --git a/kernel/timer.c b/kernel/timer.c index ee305c8d4e18..ce98685cd1cb 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -90,8 +90,13 @@ static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases; /* * Note that all tvec_bases are 2 byte aligned and lower bit of - * base in timer_list is guaranteed to be zero. Use the LSB for - * the new flag to indicate whether the timer is deferrable + * base in timer_list is guaranteed to be zero. Use the LSB to + * indicate whether the timer is deferrable. + * + * A deferrable timer will work normally when the system is busy, but + * will not cause a CPU to come out of idle just to service it; instead, + * the timer will be serviced when the CPU eventually wakes up with a + * subsequent non-deferrable timer. */ #define TBASE_DEFERRABLE_FLAG (0x1) -- cgit v1.2.3-58-ga151