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| author | J. Bruce Fields <bfields@citi.umich.edu> | 2010-07-20 15:23:15 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2010-07-23 15:08:12 +0200 |
| commit | 866e26115cba6b59cec669b6307599e3e4440491 (patch) | |
| tree | d6a4920f298608e23c8fc56f8902ae5773be8fc4 /kernel/timer.c | |
| parent | b37fa16e78d6f9790462b3181602a26b5af36260 (diff) | |
| download | lwn-866e26115cba6b59cec669b6307599e3e4440491.tar.gz lwn-866e26115cba6b59cec669b6307599e3e4440491.zip | |
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 <bfields@citi.umich.edu>
Cc: johnstul@us.ibm.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/timer.c')
| -rw-r--r-- | kernel/timer.c | 9 |
1 files changed, 7 insertions, 2 deletions
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) |