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Implemented uma_zone_set_warning(9) function that sets a warning, which

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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
This commit is contained in:
Pawel Jakub Dawidek 2012-12-07 22:27:13 +00:00
parent 45fe0bf7e4
commit 2f891cd504
4 changed files with 64 additions and 3 deletions
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17
share/man/man9/zone.9
View File

@ -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 because appropriate synchronisation to
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

12
sys/vm/uma.h
View File

@ -475,6 +475,18 @@ int uma_zone_set_max(uma_zone_t zone, int nitems);
*/
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
*

34
sys/vm/uma_core.c
View File

@ -265,6 +265,11 @@ SYSCTL_PROC(_vm, OID_AUTO, zone_count, CTLFLAG_RD|CTLTYPE_INT,
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 *udata, int flags)
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 zone, int flags)
* 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, uma_keg_t last, int rflags)
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;
@ -2880,6 +2902,16 @@ uma_zone_get_max(uma_zone_t zone)
return (nitems);
}
/* 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)

4
sys/vm/uma_int.h
View File

@ -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.