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Avoid DI recursion when reclaim_pv_chunk() is called from

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pmap_advise() or pmap_remove().

Reported and tested by:	pho (previous version)
Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
kib 2017-08-07 17:29:54 +00:00
parent fdfd6e6d57
commit e8a9dbdea0
1 changed files with 35 additions and 15 deletions
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50
sys/amd64/amd64/pmap.c
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@ -428,8 +428,15 @@ static struct lock_object invl_gen_ts = {
.lo_name = "invlts",
};
static bool
pmap_not_in_di(void)
{
return (curthread->td_md.md_invl_gen.gen == 0);
}
#define PMAP_ASSERT_NOT_IN_DI() \
KASSERT(curthread->td_md.md_invl_gen.gen == 0, ("DI already started"))
KASSERT(pmap_not_in_di(), ("DI already started"))
/*
* Start a new Delayed Invalidation (DI) block of code, executed by
@ -2856,6 +2863,19 @@ SYSCTL_INT(_vm_pmap, OID_AUTO, pv_entry_spare, CTLFLAG_RD, &pv_entry_spare, 0,
"Current number of spare pv entries");
#endif
static void
reclaim_pv_chunk_leave_pmap(pmap_t pmap, pmap_t locked_pmap, bool start_di)
{
if (pmap == NULL)
return;
pmap_invalidate_all(pmap);
if (pmap != locked_pmap)
PMAP_UNLOCK(pmap);
if (start_di)
pmap_delayed_invl_finished();
}
/*
* We are in a serious low memory condition. Resort to
* drastic measures to free some pages so we can allocate
@ -2883,6 +2903,7 @@ reclaim_pv_chunk(pmap_t locked_pmap, struct rwlock **lockp)
struct spglist free;
uint64_t inuse;
int bit, field, freed;
bool start_di;
PMAP_LOCK_ASSERT(locked_pmap, MA_OWNED);
KASSERT(lockp != NULL, ("reclaim_pv_chunk: lockp is NULL"));
@ -2891,19 +2912,21 @@ reclaim_pv_chunk(pmap_t locked_pmap, struct rwlock **lockp)
PG_G = PG_A = PG_M = PG_RW = 0;
SLIST_INIT(&free);
TAILQ_INIT(&new_tail);
pmap_delayed_invl_started();
/*
* A delayed invalidation block should already be active if
* pmap_advise() or pmap_remove() called this function by way
* of pmap_demote_pde_locked().
*/
start_di = pmap_not_in_di();
mtx_lock(&pv_chunks_mutex);
while ((pc = TAILQ_FIRST(&pv_chunks)) != NULL && SLIST_EMPTY(&free)) {
TAILQ_REMOVE(&pv_chunks, pc, pc_lru);
mtx_unlock(&pv_chunks_mutex);
if (pmap != pc->pc_pmap) {
if (pmap != NULL) {
pmap_invalidate_all(pmap);
if (pmap != locked_pmap)
PMAP_UNLOCK(pmap);
}
pmap_delayed_invl_finished();
pmap_delayed_invl_started();
reclaim_pv_chunk_leave_pmap(pmap, locked_pmap,
start_di);
pmap = pc->pc_pmap;
/* Avoid deadlock and lock recursion. */
if (pmap > locked_pmap) {
@ -2920,6 +2943,8 @@ reclaim_pv_chunk(pmap_t locked_pmap, struct rwlock **lockp)
PG_A = pmap_accessed_bit(pmap);
PG_M = pmap_modified_bit(pmap);
PG_RW = pmap_rw_bit(pmap);
if (start_di)
pmap_delayed_invl_started();
}
/*
@ -2994,12 +3019,7 @@ reclaim_pv_chunk(pmap_t locked_pmap, struct rwlock **lockp)
}
TAILQ_CONCAT(&pv_chunks, &new_tail, pc_lru);
mtx_unlock(&pv_chunks_mutex);
if (pmap != NULL) {
pmap_invalidate_all(pmap);
if (pmap != locked_pmap)
PMAP_UNLOCK(pmap);
}
pmap_delayed_invl_finished();
reclaim_pv_chunk_leave_pmap(pmap, locked_pmap, start_di);
if (m_pc == NULL && !SLIST_EMPTY(&free)) {
m_pc = SLIST_FIRST(&free);
SLIST_REMOVE_HEAD(&free, plinks.s.ss);