[src/trunk]: src/sys/uvm Freelist cache: drain using a high-priority xcall an...

[ad <ad%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/7782638fa43c
branches:  trunk
changeset: 466673:7782638fa43c
user:      ad <ad%NetBSD.org@localhost>
date:      Mon Dec 30 17:47:06 2019 +0000

description:
Freelist cache: drain using a high-priority xcall and re-enable now that
the pagedaemon starvation problem should be fixed.

diffstat:

 sys/uvm/uvm_pgflcache.c |  22 +++++-----------------
 1 files changed, 5 insertions(+), 17 deletions(-)

diffs (73 lines):

diff -r c38170d885a4 -r 7782638fa43c sys/uvm/uvm_pgflcache.c
--- a/sys/uvm/uvm_pgflcache.c   Mon Dec 30 17:45:53 2019 +0000
+++ b/sys/uvm/uvm_pgflcache.c   Mon Dec 30 17:47:06 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_pgflcache.c,v 1.3 2019/12/29 15:45:28 ad Exp $     */
+/*     $NetBSD: uvm_pgflcache.c,v 1.4 2019/12/30 17:47:06 ad Exp $     */
 
 /*-
  * Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -43,7 +43,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_pgflcache.c,v 1.3 2019/12/29 15:45:28 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_pgflcache.c,v 1.4 2019/12/30 17:47:06 ad Exp $");
 
 #include "opt_uvm.h"
 #include "opt_multiprocessor.h"
@@ -99,9 +99,7 @@
 };
 
 static kmutex_t                uvm_pgflcache_lock;
-static kcondvar_t      uvm_pgflcache_cv;
 static int             uvm_pgflcache_sem;
-static bool            uvm_pgflcache_draining;
 
 /*
  * uvm_pgflcache_fill: fill specified freelist/color from global list
@@ -318,17 +316,9 @@
        /* First one in starts draining.  Everyone else waits. */
        mutex_enter(&uvm_pgflcache_lock);
        if (uvm_pgflcache_sem++ == 0) {
-               uvm_pgflcache_draining = true;
-               mutex_exit(&uvm_pgflcache_lock);
-               where = xc_broadcast(0, uvm_pgflcache_fini_cpu, NULL, NULL);
+               where = xc_broadcast(XC_HIGHPRI, uvm_pgflcache_fini_cpu,
+                   (void *)1, NULL);
                xc_wait(where);
-               mutex_enter(&uvm_pgflcache_lock);
-               uvm_pgflcache_draining = false;
-               cv_broadcast(&uvm_pgflcache_cv);
-       } else {
-               while (uvm_pgflcache_draining) {
-                       cv_wait(&uvm_pgflcache_cv, &uvm_pgflcache_lock);
-               }
        }
        mutex_exit(&uvm_pgflcache_lock);
 }
@@ -349,7 +339,6 @@
 
        /* Last guy out takes care of business. */
        mutex_enter(&uvm_pgflcache_lock);
-       KASSERT(!uvm_pgflcache_draining);
        KASSERT(uvm_pgflcache_sem > 0);
        if (uvm_pgflcache_sem-- > 1) {
                mutex_exit(&uvm_pgflcache_lock);
@@ -406,7 +395,7 @@
        }
 
        /* Kick it into action. */
-       /* uvm_pgflcache_resume(); */
+       uvm_pgflcache_resume();
 }
 
 /*
@@ -419,7 +408,6 @@
 
        uvm_pgflcache_sem = 1;
        mutex_init(&uvm_pgflcache_lock, MUTEX_DEFAULT, IPL_NONE);
-       cv_init(&uvm_pgflcache_cv, "flcache");
 }
 
 #else  /* MULTIPROCESSOR */