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Index: sys/vm/vm_pageout.c
===================================================================
--- sys/vm/vm_pageout.c
+++ sys/vm/vm_pageout.c
@@ -165,11 +165,10 @@
CTLFLAG_RWTUN, &vm_pageout_update_period, 0,
"Maximum active LRU update period");
-/* Access with get_pageout_threads_per_domain(). */
-static int pageout_threads_per_domain = 1;
-SYSCTL_INT(_vm, OID_AUTO, pageout_threads_per_domain, CTLFLAG_RDTUN,
- &pageout_threads_per_domain, 0,
- "Number of worker threads comprising each per-domain pagedaemon");
+static int pageout_cpus_per_thread = 16;
+SYSCTL_INT(_vm, OID_AUTO, pageout_cpus_per_thread, CTLFLAG_RDTUN,
+ &pageout_cpus_per_thread, 0,
+ "Number of CPUs per pagedaemon worker thread");
SYSCTL_INT(_vm, OID_AUTO, lowmem_period, CTLFLAG_RWTUN, &lowmem_period, 0,
"Low memory callback period");
@@ -2200,38 +2199,29 @@
}
static int
-get_pageout_threads_per_domain(void)
+get_pageout_threads_per_domain(const struct vm_domain *vmd)
{
- static bool resolved = false;
- int half_cpus_per_dom;
-
- /*
- * This is serialized externally by the sorted autoconfig portion of
- * boot.
- */
- if (__predict_true(resolved))
- return (pageout_threads_per_domain);
+ unsigned total_pageout_threads, domain_cpus;
/*
* Semi-arbitrarily constrain pagedaemon threads to less than half the
- * total number of threads in the system as an insane upper limit.
+ * total number of CPUs in the system as an upper limit.
*/
- half_cpus_per_dom = howmany(mp_ncpus / vm_ndomains, 2);
+ if (pageout_cpus_per_thread < 2)
+ pageout_cpus_per_thread = 2;
+ else if (pageout_cpus_per_thread > mp_ncpus)
+ pageout_cpus_per_thread = mp_ncpus;
- if (pageout_threads_per_domain < 1) {
- printf("Invalid tuneable vm.pageout_threads_per_domain value: "
- "%d out of valid range: [1-%d]; clamping to 1\n",
- pageout_threads_per_domain, half_cpus_per_dom);
- pageout_threads_per_domain = 1;
- } else if (pageout_threads_per_domain > half_cpus_per_dom) {
- printf("Invalid tuneable vm.pageout_threads_per_domain value: "
- "%d out of valid range: [1-%d]; clamping to %d\n",
- pageout_threads_per_domain, half_cpus_per_dom,
- half_cpus_per_dom);
- pageout_threads_per_domain = half_cpus_per_dom;
- }
- resolved = true;
- return (pageout_threads_per_domain);
+ total_pageout_threads = howmany(mp_ncpus, pageout_cpus_per_thread);
+ domain_cpus = CPU_COUNT(&cpuset_domain[vmd->vmd_domain]);
+
+ /*
+ * Assign a portion of the total pageout threads to this domain
+ * corresponding to the fraction of CPUs in the domain. In asymmetric
+ * NUMA systems, domains with more CPUs may be allocated more threads
+ * than domains with fewer CPUs.
+ */
+ return (howmany(total_pageout_threads * domain_cpus, mp_ncpus));
}
/*
@@ -2288,7 +2278,7 @@
"pidctrl", CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "");
pidctrl_init_sysctl(&vmd->vmd_pid, SYSCTL_CHILDREN(oid));
- vmd->vmd_inactive_threads = get_pageout_threads_per_domain();
+ vmd->vmd_inactive_threads = get_pageout_threads_per_domain(vmd);
}
static void
@@ -2343,7 +2333,6 @@
p = curproc;
td = curthread;
- pageout_threads = get_pageout_threads_per_domain();
mtx_init(&vm_oom_ratelim_mtx, "vmoomr", NULL, MTX_DEF);
swap_pager_swap_init();
@@ -2363,6 +2352,7 @@
panic("starting pageout for domain %d: %d\n",
i, error);
}
+ pageout_threads = get_pageout_threads_per_domain(VM_DOMAIN(i));
for (j = 0; j < pageout_threads - 1; j++) {
error = kthread_add(vm_pageout_helper,
(void *)(uintptr_t)i, p, NULL, 0, 0,

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