svn commit: r243998 - in head: share/man/man9 sys/vm
Pawel Jakub Dawidek
pjd at FreeBSD.org
Fri Dec 7 22:27:14 UTC 2012
Author: pjd
Date: Fri Dec 7 22:27:13 2012
New Revision: 243998
URL: http://svnweb.freebsd.org/changeset/base/243998
Log:
Implemented uma_zone_set_warning(9) function that sets a warning, which
will be printed once the given zone becomes full and cannot allocate an
item. The warning will not be printed more often than every five minutes.
All UMA warnings can be globally turned off by setting sysctl/tunable
vm.zone_warnings to 0.
Discussed on: arch
Obtained from: WHEEL Systems
MFC after: 2 weeks
Modified:
head/share/man/man9/zone.9
head/sys/vm/uma.h
head/sys/vm/uma_core.c
head/sys/vm/uma_int.h
Modified: head/share/man/man9/zone.9
==============================================================================
--- head/share/man/man9/zone.9 Fri Dec 7 22:23:53 2012 (r243997)
+++ head/share/man/man9/zone.9 Fri Dec 7 22:27:13 2012 (r243998)
@@ -25,7 +25,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd October 28, 2012
+.Dd December 7, 2012
.Dt ZONE 9
.Os
.Sh NAME
@@ -37,7 +37,8 @@
.Nm uma_zdestroy ,
.Nm uma_zone_set_max,
.Nm uma_zone_get_max,
-.Nm uma_zone_get_cur
+.Nm uma_zone_get_cur,
+.Nm uma_zone_set_warning
.Nd zone allocator
.Sh SYNOPSIS
.In sys/param.h
@@ -65,6 +66,8 @@
.Fn uma_zone_get_max "uma_zone_t zone"
.Ft int
.Fn uma_zone_get_cur "uma_zone_t zone"
+.Ft void
+.Fn uma_zone_set_warning "uma_zone_t zone" "const char *warning"
.Sh DESCRIPTION
The zone allocator provides an efficient interface for managing
dynamically-sized collections of items of similar size.
@@ -213,6 +216,16 @@ The returned value is approximate becaus
determine an exact value is not performed by the implementation.
This ensures low overhead at the expense of potentially stale data being used
in the calculation.
+.Pp
+The
+.Fn uma_zone_set_warning
+function sets a warning that will be printed on the system console when the
+given zone becomes full and fails to allocate an item.
+The warning will be printed not often than every five minutes.
+Warnings can be turned off globally by setting the
+.Va vm.zone_warnings
+sysctl tunable to
+.Va 0 .
.Sh RETURN VALUES
The
.Fn uma_zalloc
Modified: head/sys/vm/uma.h
==============================================================================
--- head/sys/vm/uma.h Fri Dec 7 22:23:53 2012 (r243997)
+++ head/sys/vm/uma.h Fri Dec 7 22:27:13 2012 (r243998)
@@ -476,6 +476,18 @@ int uma_zone_set_max(uma_zone_t zone, in
int uma_zone_get_max(uma_zone_t zone);
/*
+ * Sets a warning to be printed when limit is reached
+ *
+ * Arguments:
+ * zone The zone we will warn about
+ * warning Warning content
+ *
+ * Returns:
+ * Nothing
+ */
+void uma_zone_set_warning(uma_zone_t zone, const char *warning);
+
+/*
* Obtains the approximate current number of items allocated from a zone
*
* Arguments:
Modified: head/sys/vm/uma_core.c
==============================================================================
--- head/sys/vm/uma_core.c Fri Dec 7 22:23:53 2012 (r243997)
+++ head/sys/vm/uma_core.c Fri Dec 7 22:27:13 2012 (r243998)
@@ -265,6 +265,11 @@ SYSCTL_PROC(_vm, OID_AUTO, zone_count, C
SYSCTL_PROC(_vm, OID_AUTO, zone_stats, CTLFLAG_RD|CTLTYPE_STRUCT,
0, 0, sysctl_vm_zone_stats, "s,struct uma_type_header", "Zone Stats");
+static int zone_warnings = 1;
+TUNABLE_INT("vm.zone_warnings", &zone_warnings);
+SYSCTL_INT(_vm, OID_AUTO, zone_warnings, CTLFLAG_RW, &zone_warnings, 0,
+ "Warn when UMA zones becomes full");
+
/*
* This routine checks to see whether or not it's safe to enable buckets.
*/
@@ -363,6 +368,18 @@ bucket_zone_drain(void)
zone_drain(ubz->ubz_zone);
}
+static void
+zone_log_warning(uma_zone_t zone)
+{
+ static const struct timeval warninterval = { 300, 0 };
+
+ if (!zone_warnings || zone->uz_warning == NULL)
+ return;
+
+ if (ratecheck(&zone->uz_ratecheck, &warninterval))
+ printf("[zone: %s] %s\n", zone->uz_name, zone->uz_warning);
+}
+
static inline uma_keg_t
zone_first_keg(uma_zone_t zone)
{
@@ -1432,6 +1449,8 @@ zone_ctor(void *mem, int size, void *uda
zone->uz_sleeps = 0;
zone->uz_fills = zone->uz_count = 0;
zone->uz_flags = 0;
+ zone->uz_warning = NULL;
+ timevalclear(&zone->uz_ratecheck);
keg = arg->keg;
if (arg->flags & UMA_ZONE_SECONDARY) {
@@ -2191,8 +2210,10 @@ keg_fetch_slab(uma_keg_t keg, uma_zone_t
* If this is not a multi-zone, set the FULL bit.
* Otherwise slab_multi() takes care of it.
*/
- if ((zone->uz_flags & UMA_ZFLAG_MULTI) == 0)
+ if ((zone->uz_flags & UMA_ZFLAG_MULTI) == 0) {
zone->uz_flags |= UMA_ZFLAG_FULL;
+ zone_log_warning(zone);
+ }
if (flags & M_NOWAIT)
break;
zone->uz_sleeps++;
@@ -2339,6 +2360,7 @@ zone_fetch_slab_multi(uma_zone_t zone, u
if (full && !empty) {
zone->uz_flags |= UMA_ZFLAG_FULL;
zone->uz_sleeps++;
+ zone_log_warning(zone);
msleep(zone, zone->uz_lock, PVM, "zonelimit", hz/100);
zone->uz_flags &= ~UMA_ZFLAG_FULL;
continue;
@@ -2881,6 +2903,16 @@ uma_zone_get_max(uma_zone_t zone)
}
/* See uma.h */
+void
+uma_zone_set_warning(uma_zone_t zone, const char *warning)
+{
+
+ ZONE_LOCK(zone);
+ zone->uz_warning = warning;
+ ZONE_UNLOCK(zone);
+}
+
+/* See uma.h */
int
uma_zone_get_cur(uma_zone_t zone)
{
Modified: head/sys/vm/uma_int.h
==============================================================================
--- head/sys/vm/uma_int.h Fri Dec 7 22:23:53 2012 (r243997)
+++ head/sys/vm/uma_int.h Fri Dec 7 22:27:13 2012 (r243998)
@@ -331,6 +331,10 @@ struct uma_zone {
uint16_t uz_fills; /* Outstanding bucket fills */
uint16_t uz_count; /* Highest value ub_ptr can have */
+ /* The next three fields are used to print a rate-limited warnings. */
+ const char *uz_warning; /* Warning to print on failure */
+ struct timeval uz_ratecheck; /* Warnings rate-limiting */
+
/*
* This HAS to be the last item because we adjust the zone size
* based on NCPU and then allocate the space for the zones.
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