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[212.86.226.226]) by mx.google.com with ESMTPS id e20sm10032949wiv.7.2012.06.09.08.49.17 (version=SSLv3 cipher=OTHER); Sat, 09 Jun 2012 08:49:18 -0700 (PDT) Sender: Alexander Motin Message-ID: <4FD3707B.1050407@FreeBSD.org> Date: Sat, 09 Jun 2012 18:49:15 +0300 From: Alexander Motin User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:12.0) Gecko/20120506 Thunderbird/12.0.1 MIME-Version: 1.0 To: Attilio Rao References: <201206081153.q58BrqG2056771@svn.freebsd.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Davide Italiano , svn-src-projects@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r236744 - in projects/calloutng/sys: kern sys X-BeenThere: svn-src-projects@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the src " projects" tree" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 09 Jun 2012 15:49:21 -0000 On 06/08/12 15:52, Attilio Rao wrote: > 2012/6/8 Davide Italiano: >> Author: davide >> Date: Fri Jun 8 11:53:51 2012 >> New Revision: 236744 >> URL: http://svn.freebsd.org/changeset/base/236744 >> >> Log: >> Add (experimentally) a function to the sleepqueue(9) KPI >> sleepq_set_timeout_bt() in which the timeout may be specified in terms >> of bintime rather than ticks, and which takes advantage of the new >> precision capabilities of the callout subsystem. >> >> Modify the kern_nanosleep() function so that it may rely on >> sleepq_set_timeout_bt() rather than tsleep(). >> >> Modified: >> projects/calloutng/sys/kern/kern_time.c >> projects/calloutng/sys/kern/subr_sleepqueue.c >> projects/calloutng/sys/sys/sleepqueue.h >> >> Modified: projects/calloutng/sys/kern/kern_time.c >> ============================================================================== >> --- projects/calloutng/sys/kern/kern_time.c Fri Jun 8 11:40:30 2012 (r236743) >> +++ projects/calloutng/sys/kern/kern_time.c Fri Jun 8 11:53:51 2012 (r236744) >> @@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$"); >> #include >> #include >> #include >> +#include >> #include >> #include >> #include >> @@ -352,37 +353,40 @@ static int nanowait; >> int >> kern_nanosleep(struct thread *td, struct timespec *rqt, struct timespec *rmt) >> { >> - struct timespec ts, ts2, ts3; >> - struct timeval tv; >> - int error; >> + struct timespec ts; >> + struct bintime bt, bt2, tmp; >> + int catch = 0, error; >> >> if (rqt->tv_nsec< 0 || rqt->tv_nsec>= 1000000000) >> return (EINVAL); >> if (rqt->tv_sec< 0 || (rqt->tv_sec == 0&& rqt->tv_nsec == 0)) >> return (0); >> - getnanouptime(&ts); >> - timespecadd(&ts, rqt); >> - TIMESPEC_TO_TIMEVAL(&tv, rqt); >> + binuptime(&bt); >> + timespec2bintime(rqt,&tmp); >> + bintime_add(&bt,&tmp); >> for (;;) { >> - error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp", >> - tvtohz(&tv)); >> - getnanouptime(&ts2); >> - if (error != EWOULDBLOCK) { >> - if (error == ERESTART) >> - error = EINTR; >> - if (rmt != NULL) { >> - timespecsub(&ts,&ts2); >> - if (ts.tv_sec< 0) >> - timespecclear(&ts); >> - *rmt = ts; >> - } >> + sleepq_lock(&nanowait); >> + sleepq_add(&nanowait, NULL, "nanslp", PWAIT | PCATCH, 0); >> + sleepq_set_timeout_bt(&nanowait,bt); >> + error = sleepq_timedwait_sig(&nanowait,catch); >> + binuptime(&bt2); >> + if (catch) { >> + if (error != EWOULDBLOCK) { >> + if (error == ERESTART) >> + error = EINTR; >> + if (rmt != NULL) { >> + tmp = bt; >> + bintime_sub(&tmp,&bt2); >> + bintime2timespec(&tmp,&ts); >> + if (ts.tv_sec< 0) >> + timespecclear(&ts); >> + *rmt = ts; >> + } >> return (error); >> + } >> } >> - if (timespeccmp(&ts2,&ts,>=)) >> + if (bintime_cmp(&bt2,&bt,>=)) >> return (0); >> - ts3 = ts; >> - timespecsub(&ts3,&ts2); >> - TIMESPEC_TO_TIMEVAL(&tv,&ts3); >> } >> } >> >> >> Modified: projects/calloutng/sys/kern/subr_sleepqueue.c >> ============================================================================== >> --- projects/calloutng/sys/kern/subr_sleepqueue.c Fri Jun 8 11:40:30 2012 (r236743) >> +++ projects/calloutng/sys/kern/subr_sleepqueue.c Fri Jun 8 11:53:51 2012 (r236744) >> @@ -361,6 +361,22 @@ sleepq_add(void *wchan, struct lock_obje >> * Sets a timeout that will remove the current thread from the specified >> * sleep queue after timo ticks if the thread has not already been awakened. >> */ >> +void >> +sleepq_set_timeout_bt(void *wchan, struct bintime bt) >> +{ >> + >> + struct sleepqueue_chain *sc; >> + struct thread *td; >> + >> + td = curthread; >> + sc = SC_LOOKUP(wchan); >> + mtx_assert(&sc->sc_lock, MA_OWNED); >> + MPASS(TD_ON_SLEEPQ(td)); >> + MPASS(td->td_sleepqueue == NULL); >> + MPASS(wchan != NULL); >> + callout_reset_bt_on(&td->td_slpcallout, bt, sleepq_timeout, td, PCPU_GET(cpuid)); >> +} >> + > > For this, I'd rather prefer that you patch sleepq_set_timeout() directly to be: > void sleepq_set_timeout(void *wchan, int timo, struct bintime *bt); > > Then, if you pass a NULL ptr to bt the 'timo' is used, otherwise bt is > given preference in the logic. You will need to patch the current few > callers of sleepq_set_timo() to get NULL, but it is a small patch. > I would really like that you do the same also in the callout KPI, > possibly, because this avoids a lot of code duplication. As opposite opinion, I don't like an idea of functions with both kinds of time arguments. It will break existing API/ABI (yes, rarely used, but already existing and documented) without giving any real benefits. Duplication of few code lines IMHO is not an argument at all if we are speaking about choosing API. Speaking about such a popular API as callout(9), I believe API breakage is just not an option. -- Alexander Motin