Messages in this thread | | | Date | Thu, 27 Aug 2015 23:12:21 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 3/3] timer: Reduce unnecessary sighand lock contention |
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On Thu, Aug 27, 2015 at 01:29:50PM -0700, Jason Low wrote: > On Thu, 2015-08-27 at 14:53 +0200, Frederic Weisbecker wrote: > > Sure, like: > > > > #define CPUTIMER_RUNNING 0x1 > > #define CPUTIMER_CHECKING 0x2 > > > > struct thread_group_cputimer { > > struct task_cputime_atomic cputime_atomic; > > int status; > > } > > > > So from cputimer_running() you just need to check: > > > > if (cputimer->status & CPUTIMER_RUNNING) > > > > And from run_posix_cpu_timer() fast-path: > > > > if (cputimer->status == CPUTIMER_RUNNING) > > > > so that ignores CPUTIMER_CHECKING case. > > Right, having just 1 "status" field can simply things a bit. The > (cputimer->status == CPUTIMER_RUNNING) check does appear misleading > though, since we're technically not only checking for if the "cputimer > is running". > > Maybe something like: > > int status = cputimer->status; > if ((status & CPUTIMER_RUNNING) && !(status & CPUTIMER_CHECKING)) > > makes it more obvious what's going on here.
The result is the same but it may clarify the code indeed.
Thanks.
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