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[src/trunk]: src/sys/uvm pagedaemon:
details: https://anonhg.NetBSD.org/src/rev/03df87768c80
branches: trunk
changeset: 466674:03df87768c80
user: ad <ad%NetBSD.org@localhost>
date: Mon Dec 30 18:08:37 2019 +0000
description:
pagedaemon:
- Use marker pages to keep place in the queue when scanning, rather than
relying on assumptions.
- In uvmpdpol_balancequeue(), lock the object once instead of twice.
- When draining pools, the situation is getting desperate, but try to avoid
saturating the system with xcall, lock and interrupt activity by sleeping
for 1 clock tick if being continually awoken and all pools have been
cycled through at least once.
- Pause & resume the freelist cache during pool draining.
PR kern/54209: NetBSD 8 large memory performance extremely low
PR kern/54210: NetBSD-8 processes presumably not exiting
PR kern/54727: writing a large file causes unreasonable system behaviour
diffstat:
sys/uvm/uvm_pdaemon.c | 93 +++++++++++++---------------
sys/uvm/uvm_pdaemon.h | 6 +-
sys/uvm/uvm_pdpolicy.h | 3 +-
sys/uvm/uvm_pdpolicy_clock.c | 126 +++++++++++++++++++++++++--------------
sys/uvm/uvm_pdpolicy_clockpro.c | 37 ++++++++++-
5 files changed, 159 insertions(+), 106 deletions(-)
diffs (truncated from 473 to 300 lines):
diff -r 7782638fa43c -r 03df87768c80 sys/uvm/uvm_pdaemon.c
--- a/sys/uvm/uvm_pdaemon.c Mon Dec 30 17:47:06 2019 +0000
+++ b/sys/uvm/uvm_pdaemon.c Mon Dec 30 18:08:37 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_pdaemon.c,v 1.118 2019/12/21 16:10:20 ad Exp $ */
+/* $NetBSD: uvm_pdaemon.c,v 1.119 2019/12/30 18:08:37 ad Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -66,7 +66,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_pdaemon.c,v 1.118 2019/12/21 16:10:20 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_pdaemon.c,v 1.119 2019/12/30 18:08:37 ad Exp $");
#include "opt_uvmhist.h"
#include "opt_readahead.h"
@@ -83,6 +83,7 @@
#include <uvm/uvm.h>
#include <uvm/uvm_pdpolicy.h>
+#include <uvm/uvm_pgflcache.h>
#ifdef UVMHIST
UVMHIST_DEFINE(pdhist);
@@ -598,7 +599,7 @@
* => return true if a page had an associated slot.
*/
-static bool
+bool
uvmpd_dropswap(struct vm_page *pg)
{
bool result = false;
@@ -622,50 +623,6 @@
return result;
}
-/*
- * uvmpd_trydropswap: try to free any swap allocated to this page.
- *
- * => return true if a slot is successfully freed.
- * => page interlock must be held, and will be dropped.
- */
-
-bool
-uvmpd_trydropswap(struct vm_page *pg)
-{
- kmutex_t *slock;
- bool result;
-
- if ((pg->flags & PG_BUSY) != 0) {
- mutex_exit(&pg->interlock);
- return false;
- }
-
- /*
- * lock the page's owner.
- * this will drop pg->interlock.
- */
-
- slock = uvmpd_trylockowner(pg);
- if (slock == NULL) {
- return false;
- }
-
- /*
- * skip this page if it's busy.
- */
-
- if ((pg->flags & PG_BUSY) != 0) {
- mutex_exit(slock);
- return false;
- }
-
- result = uvmpd_dropswap(pg);
-
- mutex_exit(slock);
-
- return result;
-}
-
#endif /* defined(VMSWAP) */
/*
@@ -909,6 +866,8 @@
#endif /* defined(VMSWAP) */
}
+ uvmpdpol_scanfini();
+
#if defined(VMSWAP)
swapcluster_flush(&swc, true);
#endif /* defined(VMSWAP) */
@@ -1031,17 +990,44 @@
static void
uvmpd_pool_drain_thread(void *arg)
{
- int bufcnt;
+ struct pool *firstpool, *curpool;
+ int bufcnt, lastslept;
+ bool cycled;
+ firstpool = NULL;
+ cycled = true;
for (;;) {
+ /*
+ * sleep until awoken by the pagedaemon.
+ */
mutex_enter(&uvmpd_lock);
if (!uvmpd_pool_drain_run) {
+ lastslept = hardclock_ticks;
cv_wait(&uvmpd_pool_drain_cv, &uvmpd_lock);
+ if (hardclock_ticks != lastslept) {
+ cycled = false;
+ firstpool = NULL;
+ }
}
uvmpd_pool_drain_run = false;
mutex_exit(&uvmpd_lock);
/*
+ * rate limit draining, otherwise in desperate circumstances
+ * this can totally saturate the system with xcall activity.
+ */
+ if (cycled) {
+ kpause("uvmpdlmt", false, 1, NULL);
+ cycled = false;
+ firstpool = NULL;
+ }
+
+ /*
+ * drain and temporarily disable the freelist cache.
+ */
+ uvm_pgflcache_pause();
+
+ /*
* kill unused metadata buffers.
*/
bufcnt = uvmexp.freetarg - uvm_free();
@@ -1053,9 +1039,16 @@
mutex_exit(&bufcache_lock);
/*
- * drain a pool.
+ * drain a pool, and then re-enable the freelist cache.
*/
- pool_drain(NULL);
+ (void)pool_drain(&curpool);
+ KASSERT(curpool != NULL);
+ if (firstpool == NULL) {
+ firstpool = curpool;
+ } else if (firstpool == curpool) {
+ cycled = true;
+ }
+ uvm_pgflcache_resume();
}
/*NOTREACHED*/
}
diff -r 7782638fa43c -r 03df87768c80 sys/uvm/uvm_pdaemon.h
--- a/sys/uvm/uvm_pdaemon.h Mon Dec 30 17:47:06 2019 +0000
+++ b/sys/uvm/uvm_pdaemon.h Mon Dec 30 18:08:37 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_pdaemon.h,v 1.17 2011/02/02 15:25:27 chuck Exp $ */
+/* $NetBSD: uvm_pdaemon.h,v 1.18 2019/12/30 18:08:38 ad Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -79,9 +79,9 @@
kmutex_t *uvmpd_trylockowner(struct vm_page *);
#ifdef VMSWAP
-bool uvmpd_trydropswap(struct vm_page *);
+bool uvmpd_dropswap(struct vm_page *);
#else
-#define uvmpd_trydropswap(_a_) (/*CONSTCOND*/false)
+#define uvmpd_dropswap(_a_) (/*CONSTCOND*/false)
#endif
#endif /* _KERNEL */
diff -r 7782638fa43c -r 03df87768c80 sys/uvm/uvm_pdpolicy.h
--- a/sys/uvm/uvm_pdpolicy.h Mon Dec 30 17:47:06 2019 +0000
+++ b/sys/uvm/uvm_pdpolicy.h Mon Dec 30 18:08:37 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_pdpolicy.h,v 1.4 2019/12/13 20:10:22 ad Exp $ */
+/* $NetBSD: uvm_pdpolicy.h,v 1.5 2019/12/30 18:08:38 ad Exp $ */
/*-
* Copyright (c)2005, 2006 YAMAMOTO Takashi,
@@ -51,6 +51,7 @@
void uvmpdpol_tune(void);
void uvmpdpol_scaninit(void);
+void uvmpdpol_scanfini(void);
struct vm_page *uvmpdpol_selectvictim(kmutex_t **lock);
void uvmpdpol_balancequeue(int);
diff -r 7782638fa43c -r 03df87768c80 sys/uvm/uvm_pdpolicy_clock.c
--- a/sys/uvm/uvm_pdpolicy_clock.c Mon Dec 30 17:47:06 2019 +0000
+++ b/sys/uvm/uvm_pdpolicy_clock.c Mon Dec 30 18:08:37 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_pdpolicy_clock.c,v 1.23 2019/12/27 13:13:17 ad Exp $ */
+/* $NetBSD: uvm_pdpolicy_clock.c,v 1.24 2019/12/30 18:08:38 ad Exp $ */
/* NetBSD: uvm_pdaemon.c,v 1.72 2006/01/05 10:47:33 yamt Exp $ */
/*
@@ -69,7 +69,7 @@
#else /* defined(PDSIM) */
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_pdpolicy_clock.c,v 1.23 2019/12/27 13:13:17 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_pdpolicy_clock.c,v 1.24 2019/12/30 18:08:38 ad Exp $");
#include <sys/param.h>
#include <sys/proc.h>
@@ -110,9 +110,8 @@
};
struct uvmpdpol_scanstate {
- bool ss_first;
bool ss_anonreact, ss_filereact, ss_execreact;
- struct vm_page *ss_nextpg;
+ struct vm_page ss_marker;
};
static void uvmpdpol_pageactivate_locked(struct vm_page *);
@@ -177,8 +176,20 @@
ss->ss_anonreact = anonreact;
ss->ss_filereact = filereact;
ss->ss_execreact = execreact;
+ memset(&ss->ss_marker, 0, sizeof(ss->ss_marker));
+ ss->ss_marker.flags = PG_MARKER;
+ TAILQ_INSERT_HEAD(&pdpol_state.s_inactiveq, &ss->ss_marker, pdqueue);
+ mutex_exit(&s->lock);
+}
- ss->ss_first = true;
+void
+uvmpdpol_scanfini(void)
+{
+ struct uvmpdpol_globalstate *s = &pdpol_state;
+ struct uvmpdpol_scanstate *ss = &pdpol_scanstate;
+
+ mutex_enter(&s->lock);
+ TAILQ_REMOVE(&pdpol_state.s_inactiveq, &ss->ss_marker, pdqueue);
mutex_exit(&s->lock);
}
@@ -195,19 +206,11 @@
struct vm_anon *anon;
struct uvm_object *uobj;
- if (ss->ss_first) {
- pg = TAILQ_FIRST(&pdpol_state.s_inactiveq);
- ss->ss_first = false;
- } else {
- pg = ss->ss_nextpg;
- if (pg != NULL && (pg->pqflags & PQ_INACTIVE) == 0) {
- pg = TAILQ_FIRST(&pdpol_state.s_inactiveq);
- }
- }
+ pg = TAILQ_NEXT(&ss->ss_marker, pdqueue);
if (pg == NULL) {
break;
}
- ss->ss_nextpg = TAILQ_NEXT(pg, pdqueue);
+ KASSERT((pg->flags & PG_MARKER) == 0);
uvmexp.pdscans++;
/*
@@ -225,6 +228,14 @@
}
/*
+ * now prepare to move on to the next page.
+ */
+ TAILQ_REMOVE(&pdpol_state.s_inactiveq, &ss->ss_marker,
+ pdqueue);
+ TAILQ_INSERT_AFTER(&pdpol_state.s_inactiveq, pg,
+ &ss->ss_marker, pdqueue);
+
+ /*
* enforce the minimum thresholds on different
* types of memory usage. if reusing the current
* page would reduce that type of usage below its
@@ -300,7 +311,7 @@
{
struct uvmpdpol_globalstate *s = &pdpol_state;
int inactive_shortage;
- struct vm_page *p, *nextpg;
+ struct vm_page *p, marker;
kmutex_t *lock;
/*
@@ -308,34 +319,22 @@
* our inactive target.
*/
- mutex_enter(&s->lock);
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