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| author | Konstantin Belousov <kib@FreeBSD.org> | 2021-05-28 17:10:47 +0000 |
|---|---|---|
| committer | Konstantin Belousov <kib@FreeBSD.org> | 2021-06-07 16:32:42 +0000 |
| commit | b25cbead39ca3e23de6f2a61f089da972b9f3157 (patch) | |
| tree | f02194b6e838b4268374995b95fc3d3f55f3a627 | |
| parent | 664aff03fae2594e7db640c06c9edac5cb57bc7f (diff) | |
| download | src-b25cbead39ca3e23de6f2a61f089da972b9f3157.tar.gz src-b25cbead39ca3e23de6f2a61f089da972b9f3157.zip | |
quisce_cpus(): add special handling for PDROP
(cherry picked from commit 3a68546d2377d6e9776060043372d66f07022543)
| -rw-r--r-- | sys/kern/subr_smp.c | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/sys/kern/subr_smp.c b/sys/kern/subr_smp.c index d4f8aac9e751..935fb6ee977c 100644 --- a/sys/kern/subr_smp.c +++ b/sys/kern/subr_smp.c @@ -943,25 +943,31 @@ smp_rendezvous_cpus_done(struct smp_rendezvous_cpus_retry_arg *arg) } /* + * If (prio & PDROP) == 0: * Wait for specified idle threads to switch once. This ensures that even * preempted threads have cycled through the switch function once, * exiting their codepaths. This allows us to change global pointers * with no other synchronization. + * If (prio & PDROP) != 0: + * Force the specified CPUs to switch context at least once. */ int quiesce_cpus(cpuset_t map, const char *wmesg, int prio) { struct pcpu *pcpu; - u_int gen[MAXCPU]; + u_int *gen; int error; int cpu; error = 0; - for (cpu = 0; cpu <= mp_maxid; cpu++) { - if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) - continue; - pcpu = pcpu_find(cpu); - gen[cpu] = pcpu->pc_idlethread->td_generation; + if ((prio & PDROP) == 0) { + gen = malloc(sizeof(u_int) * MAXCPU, M_TEMP, M_WAITOK); + for (cpu = 0; cpu <= mp_maxid; cpu++) { + if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) + continue; + pcpu = pcpu_find(cpu); + gen[cpu] = pcpu->pc_idlethread->td_generation; + } } for (cpu = 0; cpu <= mp_maxid; cpu++) { if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) @@ -970,8 +976,10 @@ quiesce_cpus(cpuset_t map, const char *wmesg, int prio) thread_lock(curthread); sched_bind(curthread, cpu); thread_unlock(curthread); + if ((prio & PDROP) != 0) + continue; while (gen[cpu] == pcpu->pc_idlethread->td_generation) { - error = tsleep(quiesce_cpus, prio, wmesg, 1); + error = tsleep(quiesce_cpus, prio & ~PDROP, wmesg, 1); if (error != EWOULDBLOCK) goto out; error = 0; @@ -981,6 +989,8 @@ out: thread_lock(curthread); sched_unbind(curthread); thread_unlock(curthread); + if ((prio & PDROP) == 0) + free(gen, M_TEMP); return (error); } |