Date: Fri, 25 Jul 2008 21:02:06 GMT From: John Baldwin <jhb@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 145918 for review Message-ID: <200807252102.m6PL26tx051374@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=145918 Change 145918 by jhb@jhb_mutex on 2008/07/25 21:01:26 First cut at respecting cpusets in 4BSD. Affected files ... .. //depot/projects/smpng/sys/kern/sched_4bsd.c#75 edit Differences ... ==== //depot/projects/smpng/sys/kern/sched_4bsd.c#75 (text+ko) ==== @@ -101,6 +101,9 @@ #define SKE_RUNQ_PCPU(ts) \ ((ts)->ts_runq != 0 && (ts)->ts_runq != &runq) +#define THREAD_CAN_SCHED(td, cpu) \ + CPU_ISSET((cpu), &(td)->td_cpuset->cs_mask) + static struct td_sched td_sched0; struct mtx sched_lock; @@ -118,7 +121,8 @@ static void resetpriority(struct thread *td); static void resetpriority_thread(struct thread *td); #ifdef SMP -static int forward_wakeup(int cpunum); +static int sched_pickcpu(struct thread *td); +static int forward_wakeup(int cpunum); #endif static struct kproc_desc sched_kp = { @@ -140,6 +144,7 @@ * Per-CPU run queues */ static struct runq runq_pcpu[MAXCPU]; +long runq_length[MAXCPU]; #endif static void @@ -1152,6 +1157,45 @@ } #endif /* SMP */ +#ifdef SMP +/* + * Find a CPU for this thread to run on. If it can run on any CPU, then + * this returns NOCPU. + */ +static int +sched_pickcpu(struct thread *td) +{ + int best, cpu, fullset; + + mtx_assert(&sched_lock, MA_OWNED); + + fullset = 1; + best = NOCPU; + for (cpu = 0; cpu <= mp_maxid; cpu++) { + if (CPU_ABSENT(cpu)) + continue; + if (!THREAD_CAN_SCHED(td, cpu)) { + /* + * At least one available CPU isn't in our + * set, so it isn't a "full" set. + */ + fullset = 0; + continue; + } + + if (best == NOCPU) + best = cpu; + else if (runq_length[cpu] < runq_length[best]) + best = cpu; + } + + if (fullset) + return (NOCPU); + else + return (best); +} +#endif + void sched_add(struct thread *td, int flags) #ifdef SMP @@ -1195,11 +1239,18 @@ single_cpu = 1; CTR3(KTR_RUNQ, "sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td, cpu); - } else { - CTR2(KTR_RUNQ, + } else { + /* Find a valid CPU for our cpuset */ + cpu = sched_pickcpu(td); + if (cpu == NOCPU) { + CTR2(KTR_RUNQ, "sched_add: adding td_sched:%p (td:%p) to gbl runq", ts, td); - cpu = NOCPU; - ts->ts_runq = &runq; + ts->ts_runq = &runq; + } else { + single_cpu = 1; + CTR3(KTR_RUNQ, + "sched_add: Put td_sched:%p(td:%p) on cpu%d runq", ts, td, cpu); + } } if (single_cpu && (cpu != PCPU_GET(cpuid))) { @@ -1226,6 +1277,8 @@ if ((td->td_proc->p_flag & P_NOLOAD) == 0) sched_load_add(); runq_add(ts->ts_runq, td, flags); + if (cpu != NOCPU) + runq_length[cpu]++; } #else /* SMP */ { @@ -1292,6 +1345,10 @@ if ((td->td_proc->p_flag & P_NOLOAD) == 0) sched_load_rem(); +#ifdef SMP + if (ts->ts_runq != &runq) + runq_length[ts->ts_runq - runq_pcpu]--; +#endif runq_remove(ts->ts_runq, td); TD_SET_CAN_RUN(td); } @@ -1331,6 +1388,10 @@ #endif if (td) { +#ifdef SMP + if (td == tdcpu) + runq_length[PCPU_GET(cpuid)]--; +#endif runq_remove(rq, td); td->td_flags |= TDF_DIDRUN; @@ -1515,4 +1576,17 @@ void sched_affinity(struct thread *td) { +#ifdef SMP + + THREAD_LOCK_ASSERT(td, MA_OWNED); + + /* + * See if our current CPU is in the set. If not, force a + * context switch. + */ + if (THREAD_CAN_SCHED(td, PCPU_GET(cpuid))) + return; + + mi_switch(SW_VOL, NULL); +#endif }
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