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Add some counters for per-VM page events.

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For now, just count batched page queue state operations.
vm.stats.page.queue_ops counts the number of batch entries that
successfully completed, while queue_nops counts entries that had no
effect, which occurs when the queue operation had been completed before
the batch entry was processed.

Reviewed by:	alc, kib
MFC after:	1 week
Sponsored by:	Intel, Netflix
Differential Revision:	https://reviews.freebsd.org/D21782
This commit is contained in:
Mark Johnston 2019-09-25 17:08:35 +00:00
parent ef36db58da
commit 2b93f779d2
1 changed files with 28 additions and 1 deletions
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29
sys/vm/vm_page.c
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@ -73,11 +73,12 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/counter.h>
#include <sys/domainset.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/msgbuf.h>
@ -130,6 +131,28 @@ static int vm_min_waiters;
static int vm_severe_waiters;
static int vm_pageproc_waiters;
static SYSCTL_NODE(_vm_stats, OID_AUTO, page, CTLFLAG_RD, 0,
"VM page statistics");
static counter_u64_t queue_ops = EARLY_COUNTER;
SYSCTL_COUNTER_U64(_vm_stats_page, OID_AUTO, queue_ops,
CTLFLAG_RD, &queue_ops,
"Number of batched queue operations");
static counter_u64_t queue_nops = EARLY_COUNTER;
SYSCTL_COUNTER_U64(_vm_stats_page, OID_AUTO, queue_nops,
CTLFLAG_RD, &queue_nops,
"Number of batched queue operations with no effects");
static void
counter_startup(void)
{
queue_ops = counter_u64_alloc(M_WAITOK);
queue_nops = counter_u64_alloc(M_WAITOK);
}
SYSINIT(page_counters, SI_SUB_CPU, SI_ORDER_ANY, counter_startup, NULL);
/*
* bogus page -- for I/O to/from partially complete buffers,
* or for paging into sparsely invalid regions.
@ -3117,6 +3140,7 @@ vm_pqbatch_process_page(struct vm_pagequeue *pq, vm_page_t m)
if (__predict_true((qflags & PGA_ENQUEUED) != 0))
vm_pagequeue_remove(pq, m);
vm_page_dequeue_complete(m);
counter_u64_add(queue_ops, 1);
} else if ((qflags & (PGA_REQUEUE | PGA_REQUEUE_HEAD)) != 0) {
if ((qflags & PGA_ENQUEUED) != 0)
TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
@ -3141,6 +3165,9 @@ vm_pqbatch_process_page(struct vm_pagequeue *pq, vm_page_t m)
vm_page_aflag_clear(m, qflags & (PGA_REQUEUE |
PGA_REQUEUE_HEAD));
counter_u64_add(queue_ops, 1);
} else {
counter_u64_add(queue_nops, 1);
}
}