On Tue, Aug 11, 2020 at 08:37:45PM +0000, Conrad Meyer wrote: > Author: cem > Date: Tue Aug 11 20:37:45 2020 > New Revision: 364129 > URL: https://svnweb.freebsd.org/changeset/base/364129 > > Log: > Add support for multithreading the inactive queue pageout within a domain. > > In very high throughput workloads, the inactive scan can become overwhelmed > as you have many cores producing pages and a single core freeing. Since > Mark's introduction of batched pagequeue operations, we can now run multiple > inactive threads working on independent batches. > > To avoid confusing the pid and other control algorithms, I (Jeff) do this in > a mpi-like fan out and collect model that is driven from the primary page > daemon. It decides whether the shortfall can be overcome with a single > thread and if not dispatches multiple threads and waits for their results. > > The heuristic is based on timing the pageout activity and averaging a > pages-per-second variable which is exponentially decayed. This is visible in > sysctl and may be interesting for other purposes. > > I (Jeff) have verified that this does indeed double our paging throughput > when used with two threads. With four we tend to run into other contention > problems. For now I would like to commit this infrastructure with only a > single thread enabled. > > The number of worker threads per domain can be controlled with the > 'vm.pageout_threads_per_domain' tunable. > > Submitted by: jeff (earlier version) > Discussed with: markj > Tested by: pho > Sponsored by: probably Netflix (based on contemporary commits) > Differential Revision: https://reviews.freebsd.org/D21629 > > Modified: > head/sys/vm/vm_meter.c > head/sys/vm/vm_page.c > head/sys/vm/vm_page.h > head/sys/vm/vm_pageout.c > head/sys/vm/vm_pagequeue.h > > Modified: head/sys/vm/vm_meter.c > ============================================================================== > --- head/sys/vm/vm_meter.c Tue Aug 11 17:54:10 2020 (r364128) > +++ head/sys/vm/vm_meter.c Tue Aug 11 20:37:45 2020 (r364129) > @@ -552,6 +552,9 @@ vm_domain_stats_init(struct vm_domain *vmd, struct sys > SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(oid), OID_AUTO, > "free_severe", CTLFLAG_RD, &vmd->vmd_free_severe, 0, > "Severe free pages"); > + SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(oid), OID_AUTO, > + "inactive_pps", CTLFLAG_RD, &vmd->vmd_inactive_pps, 0, > + "inactive pages freed/second"); > > } > > > Modified: head/sys/vm/vm_page.c > ============================================================================== > --- head/sys/vm/vm_page.c Tue Aug 11 17:54:10 2020 (r364128) > +++ head/sys/vm/vm_page.c Tue Aug 11 20:37:45 2020 (r364129) > @@ -421,7 +421,7 @@ sysctl_vm_page_blacklist(SYSCTL_HANDLER_ARGS) > * In principle, this function only needs to set the flag PG_MARKER. > * Nonetheless, it write busies the page as a safety precaution. > */ > -static void > +void > vm_page_init_marker(vm_page_t marker, int queue, uint16_t aflags) > { > > @@ -2488,7 +2488,7 @@ vm_page_zone_import(void *arg, void **store, int cnt, > * main purpose is to replenish the store of free pages. > */ > if (vmd->vmd_severeset || curproc == pageproc || > - !_vm_domain_allocate(vmd, VM_ALLOC_NORMAL, cnt)) > + !_vm_domain_allocate(vmd, VM_ALLOC_SYSTEM, cnt)) Why this change needed ?
> return (0); > domain = vmd->vmd_domain; > vm_domain_free_lock(vmd); > _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "[email protected]"
