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Ensure that deactivated pages that are not expected to be reused are

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reclaimed in FIFO order by the pagedaemon.  Previously we would enqueue
such pages at the head of the inactive queue, yielding a LIFO reclaim order.

Reviewed by:	alc
MFC after:	2 weeks
Sponsored by:	EMC / Isilon Storage Division
This commit is contained in:
Mark Johnston 2015-11-08 01:36:18 +00:00
parent 1c01e4f876
commit 7e78597f04
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=290529
3 changed files with 16 additions and 9 deletions
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21
sys/vm/vm_page.c
View File

@ -2536,14 +2536,16 @@ vm_page_unwire(vm_page_t m, uint8_t queue)
* processes. This optimization causes one-time-use metadata to be
* reused more quickly.
*
* Normally athead is 0 resulting in LRU operation. athead is set
* to 1 if we want this page to be 'as if it were placed in the cache',
* except without unmapping it from the process address space.
* Normally noreuse is FALSE, resulting in LRU operation. noreuse is set
* to TRUE if we want this page to be 'as if it were placed in the cache',
* except without unmapping it from the process address space. In
* practice this is implemented by inserting the page at the head of the
* queue, using a marker page to guide FIFO insertion ordering.
*
* The page must be locked.
*/
static inline void
_vm_page_deactivate(vm_page_t m, int athead)
_vm_page_deactivate(vm_page_t m, boolean_t noreuse)
{
struct vm_pagequeue *pq;
int queue;
@ -2554,7 +2556,7 @@ _vm_page_deactivate(vm_page_t m, int athead)
* Ignore if the page is already inactive, unless it is unlikely to be
* reactivated.
*/
if ((queue = m->queue) == PQ_INACTIVE && !athead)
if ((queue = m->queue) == PQ_INACTIVE && !noreuse)
return;
if (m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0) {
pq = &vm_phys_domain(m)->vmd_pagequeues[PQ_INACTIVE];
@ -2569,8 +2571,9 @@ _vm_page_deactivate(vm_page_t m, int athead)
vm_pagequeue_lock(pq);
}
m->queue = PQ_INACTIVE;
if (athead)
TAILQ_INSERT_HEAD(&pq->pq_pl, m, plinks.q);
if (noreuse)
TAILQ_INSERT_BEFORE(&vm_phys_domain(m)->vmd_inacthead,
m, plinks.q);
else
TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
vm_pagequeue_cnt_inc(pq);
@ -2587,7 +2590,7 @@ void
vm_page_deactivate(vm_page_t m)
{
_vm_page_deactivate(m, 0);
_vm_page_deactivate(m, FALSE);
}
/*
@ -2600,7 +2603,7 @@ void
vm_page_deactivate_noreuse(vm_page_t m)
{
_vm_page_deactivate(m, 1);
_vm_page_deactivate(m, TRUE);
}
/*

1
sys/vm/vm_page.h
View File

@ -229,6 +229,7 @@ struct vm_domain {
int vmd_pass; /* local pagedaemon pass */
int vmd_last_active_scan;
struct vm_page vmd_marker; /* marker for pagedaemon private use */
struct vm_page vmd_inacthead; /* marker for LRU-defeating insertions */
};
extern struct vm_domain vm_dom[MAXMEMDOM];

3
sys/vm/vm_pageout.c
View File

@ -1630,6 +1630,9 @@ vm_pageout_worker(void *arg)
KASSERT(domain->vmd_segs != 0, ("domain without segments"));
domain->vmd_last_active_scan = ticks;
vm_pageout_init_marker(&domain->vmd_marker, PQ_INACTIVE);
vm_pageout_init_marker(&domain->vmd_inacthead, PQ_INACTIVE);
TAILQ_INSERT_HEAD(&domain->vmd_pagequeues[PQ_INACTIVE].pq_pl,
&domain->vmd_inacthead, plinks.q);
/*
* The pageout daemon worker is never done, so loop forever.