Author: kib
Date: Mon Aug 14 11:06:09 2017
New Revision: 322492
URL: https://svnweb.freebsd.org/changeset/base/322492
Log:
MFC r322175:
Avoid DI recursion when reclaim_pv_chunk() is called from
pmap_advise() or pmap_remove().
Modified:
stable/11/sys/amd64/amd64/pmap.c
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/amd64/amd64/pmap.c
==============================================================================
--- stable/11/sys/amd64/amd64/pmap.c Mon Aug 14 11:04:06 2017
(r322491)
+++ stable/11/sys/amd64/amd64/pmap.c Mon Aug 14 11:06:09 2017
(r322492)
@@ -430,8 +430,15 @@ 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
@@ -2847,6 +2854,19 @@ SYSCTL_INT(_vm_pmap, OID_AUTO, pv_entry_spare, CTLFLAG
"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
@@ -2874,6 +2894,7 @@ reclaim_pv_chunk(pmap_t locked_pmap, struct rwlock **l
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"));
@@ -2882,19 +2903,21 @@ reclaim_pv_chunk(pmap_t locked_pmap, struct rwlock **l
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) {
@@ -2911,6 +2934,8 @@ reclaim_pv_chunk(pmap_t locked_pmap, struct rwlock **l
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();
}
/*
@@ -2985,12 +3010,7 @@ reclaim_pv_chunk(pmap_t locked_pmap, struct rwlock **l
}
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);
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