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[src/trunk]: src/sys/arch/aarch64 rather than using flags to resolve nested l...
details: https://anonhg.NetBSD.org/src/rev/92613b9fabf9
branches: trunk
changeset: 324830:92613b9fabf9
user: ryo <ryo%NetBSD.org@localhost>
date: Mon Jul 23 22:32:22 2018 +0000
description:
rather than using flags to resolve nested locks, reserve pool_cache before locking.
diffstat:
sys/arch/aarch64/aarch64/pmap.c | 82 +++++++++++++---------------------------
sys/arch/aarch64/include/cpu.h | 5 +--
2 files changed, 28 insertions(+), 59 deletions(-)
diffs (194 lines):
diff -r 5ea7cfe2ff7e -r 92613b9fabf9 sys/arch/aarch64/aarch64/pmap.c
--- a/sys/arch/aarch64/aarch64/pmap.c Mon Jul 23 00:51:40 2018 +0000
+++ b/sys/arch/aarch64/aarch64/pmap.c Mon Jul 23 22:32:22 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.11 2018/07/21 13:08:35 ryo Exp $ */
+/* $NetBSD: pmap.c,v 1.12 2018/07/23 22:32:22 ryo Exp $ */
/*
* Copyright (c) 2017 Ryo Shimizu <ryo%nerv.org@localhost>
@@ -27,7 +27,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.11 2018/07/21 13:08:35 ryo Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.12 2018/07/23 22:32:22 ryo Exp $");
#include "opt_arm_debug.h"
#include "opt_ddb.h"
@@ -149,10 +149,6 @@
#define LX_BLKPAG_ATTR_DEVICE_MEM __SHIFTIN(3, LX_BLKPAG_ATTR_INDX)
#define LX_BLKPAG_ATTR_MASK LX_BLKPAG_ATTR_INDX
-/* flags for cpu_info->ci_pmap_flags */
-#define CI_PMAP_FLAGS_KPM_OWNLOCKED 0x00000001
-
-
struct pv_entry {
TAILQ_ENTRY(pv_entry) pv_link;
struct pmap *pv_pmap;
@@ -194,33 +190,15 @@
}
-static inline int
-pm_kpm_ownlocked(struct pmap *pm)
-{
- if (pm != pmap_kernel())
- return false;
-
- return curcpu()->ci_pmap_flags & CI_PMAP_FLAGS_KPM_OWNLOCKED;
-}
-
static inline void
pm_lock(struct pmap *pm)
{
mutex_enter(&pm->pm_lock);
-
- /*
- * remember locking myself if pm is pmap_kernel.
- * mutex_owned() works only for adaptive lock, therefore we cannot use.
- */
- if (pm == pmap_kernel())
- curcpu()->ci_pmap_flags |= CI_PMAP_FLAGS_KPM_OWNLOCKED;
}
static inline void
pm_unlock(struct pmap *pm)
{
- if (pm == pmap_kernel())
- curcpu()->ci_pmap_flags &= ~CI_PMAP_FLAGS_KPM_OWNLOCKED;
mutex_exit(&pm->pm_lock);
}
@@ -973,7 +951,7 @@
#endif /* PMAP_PV_DEBUG & DDB */
static int
-_pmap_enter_pv(struct vm_page *pg, struct pmap *pm, vaddr_t va,
+_pmap_enter_pv(struct vm_page *pg, struct pmap *pm, struct pv_entry **pvp, vaddr_t va,
pt_entry_t *ptep, paddr_t pa, u_int flags)
{
struct vm_page_md *md;
@@ -999,10 +977,14 @@
if (pv == NULL) {
pmap_pv_unlock(md);
- /* create and link new pv */
- pv = pool_cache_get(&_pmap_pv_pool, PR_NOWAIT);
+ /*
+ * create and link new pv.
+ * pv is already allocated at beginning of _pmap_enter().
+ */
+ pv = *pvp;
if (pv == NULL)
return ENOMEM;
+ *pvp = NULL;
pv->pv_pmap = pm;
pv->pv_va = va;
@@ -1300,6 +1282,7 @@
u_int flags, bool kenter)
{
struct vm_page *pg;
+ struct pv_entry *spv;
pd_entry_t pde;
pt_entry_t attr, pte, *ptep;
pd_entry_t *l0, *l1, *l2, *l3;
@@ -1307,7 +1290,6 @@
uint32_t mdattr;
unsigned int idx;
int error = 0;
- int pm_locked;
const bool user = (pm != pmap_kernel());
bool executable;
@@ -1348,21 +1330,19 @@
else
pg = PHYS_TO_VM_PAGE(pa);
-#ifdef PMAPCOUNTERS
- if (pg == NULL) {
- PMAP_COUNT(unmanaged_mappings);
+ if (pg != NULL) {
+ PMAP_COUNT(managed_mappings);
+ /*
+ * allocate pv in advance of pm_lock() to avoid locking myself.
+ * pool_cache_get() may call pmap_kenter() internally.
+ */
+ spv = pool_cache_get(&_pmap_pv_pool, PR_NOWAIT);
} else {
- PMAP_COUNT(managed_mappings);
+ PMAP_COUNT(unmanaged_mappings);
+ spv = NULL;
}
-#endif
- /*
- * _pmap_enter() may be called recursively. In case of
- * pmap_enter() -> _pmap_enter_pv() -> pool_cache_get() -> pmap_kenter()
- */
- pm_locked = pm_kpm_ownlocked(pm);
- if (!pm_locked)
- pm_lock(pm);
+ pm_lock(pm);
/*
* traverse L0 -> L1 -> L2 -> L3 table with growing pdp if needed.
@@ -1440,21 +1420,9 @@
pm->pm_stats.resident_count--;
}
- /*
- * _pmap_enter_pv() may call pmap_kenter() internally.
- * don't allocate pv_entry (don't call _pmap_enter_pv) when kenter mode.
- * `pg' have got to be NULL if (kenter).
- */
mdattr = VM_PROT_READ | VM_PROT_WRITE;
if (pg != NULL) {
- if (pm != pmap_kernel()) {
- /* avoid deadlock (see above comment) */
- pm_lock(pmap_kernel());
- }
- error = _pmap_enter_pv(pg, pm, va, ptep, pa, flags);
- if (pm != pmap_kernel()) {
- pm_unlock(pmap_kernel());
- }
+ error = _pmap_enter_pv(pg, pm, &spv, va, ptep, pa, flags);
if (error != 0) {
/*
@@ -1515,8 +1483,12 @@
pm->pm_stats.resident_count++;
done:
- if (!pm_locked)
- pm_unlock(pm);
+ pm_unlock(pm);
+
+ /* spare pv was not used. discard */
+ if (spv != NULL)
+ pool_cache_put(&_pmap_pv_pool, spv);
+
return error;
}
diff -r 5ea7cfe2ff7e -r 92613b9fabf9 sys/arch/aarch64/include/cpu.h
--- a/sys/arch/aarch64/include/cpu.h Mon Jul 23 00:51:40 2018 +0000
+++ b/sys/arch/aarch64/include/cpu.h Mon Jul 23 22:32:22 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cpu.h,v 1.4 2018/07/21 13:08:35 ryo Exp $ */
+/* $NetBSD: cpu.h,v 1.5 2018/07/23 22:32:22 ryo Exp $ */
/*-
* Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -78,9 +78,6 @@
struct evcnt ci_vfp_reuse;
struct evcnt ci_vfp_save;
struct evcnt ci_vfp_release;
-
- /* per cpu pmap private */
- uint64_t ci_pmap_flags;
};
static inline struct cpu_info *
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