Date: Tue, 20 Nov 2012 15:33:48 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r243341 - head/sys/kern Message-ID: <201211201533.qAKFXm80046544@svn.freebsd.org>
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Author: kib Date: Tue Nov 20 15:33:48 2012 New Revision: 243341 URL: http://svnweb.freebsd.org/changeset/base/243341 Log: Add a special meaning to the negative ticks argument for taskqueue_enqueue_timeout(). Do not rearm the callout if it is already armed and the ticks is negative. Otherwise rearm it to fire in abs(ticks) ticks in the future. The intended use is to call taskqueue_enqueue_timeout() for the given timeout_task with the same negative ticks argument. As result, the task is scheduled to execute not further than abs(ticks) ticks in future, and the consequent enqueues are coalesced until the already scheduled task is finished. Reviewed by: rwatson Tested by: Markus Gebert <markus.gebert@hostpoint.ch> MFC after: 2 weeks Modified: head/sys/kern/subr_taskqueue.c Modified: head/sys/kern/subr_taskqueue.c ============================================================================== --- head/sys/kern/subr_taskqueue.c Tue Nov 20 15:25:00 2012 (r243340) +++ head/sys/kern/subr_taskqueue.c Tue Nov 20 15:33:48 2012 (r243341) @@ -252,9 +252,13 @@ taskqueue_enqueue_timeout(struct taskque } else { queue->tq_callouts++; timeout_task->f |= DT_CALLOUT_ARMED; + if (ticks < 0) + ticks = -ticks; /* Ignore overflow. */ + } + if (ticks > 0) { + callout_reset(&timeout_task->c, ticks, + taskqueue_timeout_func, timeout_task); } - callout_reset(&timeout_task->c, ticks, taskqueue_timeout_func, - timeout_task); } TQ_UNLOCK(queue); return (res);
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