Module Name: src
Committed By: rmind
Date: Fri Apr 1 00:47:12 UTC 2011
Modified Files:
src/sys/uvm: uvm_page.c
Log Message:
uvm_pageidlezero: use try-lock to not occupy uvm_fpageqlock, which may
be on demand by other CPUs. Reduces lock contention in some workloads
on many CPU (8+) systems.
Tested by tls@.
To generate a diff of this commit:
cvs rdiff -u -r1.171 -r1.172 src/sys/uvm/uvm_page.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/uvm/uvm_page.c
diff -u src/sys/uvm/uvm_page.c:1.171 src/sys/uvm/uvm_page.c:1.172
--- src/sys/uvm/uvm_page.c:1.171 Wed Feb 2 17:53:42 2011
+++ src/sys/uvm/uvm_page.c Fri Apr 1 00:47:11 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_page.c,v 1.171 2011/02/02 17:53:42 chuck Exp $ */
+/* $NetBSD: uvm_page.c,v 1.172 2011/04/01 00:47:11 rmind Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -66,7 +66,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_page.c,v 1.171 2011/02/02 17:53:42 chuck Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_page.c,v 1.172 2011/04/01 00:47:11 rmind Exp $");
#include "opt_ddb.h"
#include "opt_uvmhist.h"
@@ -1716,6 +1716,7 @@
struct pgfreelist *pgfl, *gpgfl;
struct uvm_cpu *ucpu;
int free_list, firstbucket, nextbucket;
+ bool lcont = false;
ucpu = curcpu()->ci_data.cpu_uvm;
if (!ucpu->page_idle_zero ||
@@ -1723,7 +1724,10 @@
ucpu->page_idle_zero = false;
return;
}
- mutex_enter(&uvm_fpageqlock);
+ if (!mutex_tryenter(&uvm_fpageqlock)) {
+ /* Contention: let other CPUs to use the lock. */
+ return;
+ }
firstbucket = ucpu->page_free_nextcolor;
nextbucket = firstbucket;
do {
@@ -1735,7 +1739,7 @@
gpgfl = &uvm.page_free[free_list];
while ((pg = LIST_FIRST(&pgfl->pgfl_buckets[
nextbucket].pgfl_queues[PGFL_UNKNOWN])) != NULL) {
- if (sched_curcpu_runnable_p()) {
+ if (lcont || sched_curcpu_runnable_p()) {
goto quit;
}
LIST_REMOVE(pg, pageq.list); /* global list */
@@ -1773,7 +1777,12 @@
#endif /* PMAP_PAGEIDLEZERO */
pg->flags |= PG_ZERO;
- mutex_spin_enter(&uvm_fpageqlock);
+ if (!mutex_tryenter(&uvm_fpageqlock)) {
+ lcont = true;
+ mutex_spin_enter(&uvm_fpageqlock);
+ } else {
+ lcont = false;
+ }
pg->pqflags = PQ_FREE;
LIST_INSERT_HEAD(&gpgfl->pgfl_buckets[
nextbucket].pgfl_queues[PGFL_ZEROS],
