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[src/trunk]: src/sys/arch/aarch64 - free empty page tables pages if reach a c...
details: https://anonhg.NetBSD.org/src/rev/a822b6d11d61
branches: trunk
changeset: 455645:a822b6d11d61
user: ryo <ryo%NetBSD.org@localhost>
date: Mon Apr 08 21:18:22 2019 +0000
description:
- free empty page tables pages if reach a certain usage.
- need to lock at removing an old pg (_pmap_remove_pv) in _pmap_enter()
diffstat:
sys/arch/aarch64/aarch64/pmap.c | 137 +++++++++++++++++++++++++++++++++------
sys/arch/aarch64/include/asan.h | 4 +-
sys/arch/aarch64/include/pmap.h | 5 +-
3 files changed, 119 insertions(+), 27 deletions(-)
diffs (truncated from 321 to 300 lines):
diff -r 1fd1263a36f4 -r a822b6d11d61 sys/arch/aarch64/aarch64/pmap.c
--- a/sys/arch/aarch64/aarch64/pmap.c Mon Apr 08 20:18:14 2019 +0000
+++ b/sys/arch/aarch64/aarch64/pmap.c Mon Apr 08 21:18:22 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.39 2019/04/06 18:30:20 ryo Exp $ */
+/* $NetBSD: pmap.c,v 1.40 2019/04/08 21:18:22 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 1.39 2019/04/06 18:30:20 ryo Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.40 2019/04/08 21:18:22 ryo Exp $");
#include "opt_arm_debug.h"
#include "opt_ddb.h"
@@ -194,6 +194,7 @@
#define pv_next pv_link.tqe_next
#define L3INDEXMASK (L3_SIZE * Ln_ENTRIES - 1)
+#define PDPSWEEP_TRIGGER 512
void atomic_add_16(volatile uint16_t *, int16_t);
uint16_t atomic_add_16_nv(volatile uint16_t *, int16_t);
@@ -439,6 +440,7 @@
kpm = pmap_kernel();
kpm->pm_asid = 0;
kpm->pm_refcnt = 1;
+ kpm->pm_idlepdp = 0;
kpm->pm_l0table = l0;
kpm->pm_l0table_pa = l0pa;
kpm->pm_activated = true;
@@ -564,7 +566,7 @@
}
paddr_t
-pmap_alloc_pdp(struct pmap *pm, struct vm_page **pgp, bool waitok)
+pmap_alloc_pdp(struct pmap *pm, struct vm_page **pgp, int flags, bool waitok)
{
paddr_t pa;
struct vm_page *pg;
@@ -573,9 +575,10 @@
UVMHIST_CALLED(pmaphist);
if (uvm.page_init_done) {
+ int aflags = ((flags & PMAP_CANFAIL) ? 0 : UVM_PGA_USERESERVE) |
+ UVM_PGA_ZERO;
retry:
- pg = uvm_pagealloc(NULL, 0, NULL,
- UVM_PGA_USERESERVE | UVM_PGA_ZERO);
+ pg = uvm_pagealloc(NULL, 0, NULL, aflags);
if (pg == NULL) {
if (waitok) {
uvm_wait("pmap_alloc_pdp");
@@ -620,6 +623,61 @@
PMAP_COUNT(pdp_free);
}
+/* free empty page table pages */
+static int
+_pmap_sweep_pdp(struct pmap *pm)
+{
+ struct vm_page *pg, *tmp;
+ pd_entry_t *ptep_in_parent, opte;
+ paddr_t pa, pdppa;
+ int nsweep;
+ uint16_t wirecount;
+
+ nsweep = 0;
+ TAILQ_FOREACH_SAFE(pg, &pm->pm_vmlist, mdpage.mdpg_vmlist, tmp) {
+ if (pg->wire_count != 1)
+ continue;
+
+ pa = VM_PAGE_TO_PHYS(pg);
+ if (pa == pm->pm_l0table_pa)
+ continue;
+
+ ptep_in_parent = VM_PAGE_TO_MD(pg)->mdpg_ptep_parent;
+ if (ptep_in_parent == NULL) {
+ /* no parent */
+ pmap_free_pdp(pm, pg);
+ nsweep++;
+ continue;
+ }
+
+ /* unlink from parent */
+ opte = atomic_swap_64(ptep_in_parent, 0);
+ KASSERT(lxpde_valid(opte));
+ wirecount = atomic_add_16_nv(&pg->wire_count, -1); /* 1 -> 0 */
+ KASSERT(wirecount == 0);
+ pmap_free_pdp(pm, pg);
+ nsweep++;
+
+ /* L3->L2->L1. no need for L0 */
+ pdppa = AARCH64_KVA_TO_PA(trunc_page((vaddr_t)ptep_in_parent));
+ if (pdppa == pm->pm_l0table_pa)
+ continue;
+
+ pg = PHYS_TO_VM_PAGE(pdppa);
+ KASSERT(pg != NULL);
+ KASSERTMSG(pg->wire_count >= 1,
+ "wire_count=%d", pg->wire_count);
+ /* decrement wire_count of parent */
+ wirecount = atomic_add_16_nv(&pg->wire_count, -1);
+ KASSERTMSG(pg->wire_count <= (Ln_ENTRIES + 1),
+ "pm=%p[%d], pg=%p, wire_count=%d",
+ pm, pm->pm_asid, pg, pg->wire_count);
+ }
+ atomic_swap_uint(&pm->pm_idlepdp, 0);
+
+ return nsweep;
+}
+
static void
_pmap_free_pdp_all(struct pmap *pm)
{
@@ -1270,11 +1328,12 @@
pm = pool_cache_get(&_pmap_cache, PR_WAITOK);
memset(pm, 0, sizeof(*pm));
pm->pm_refcnt = 1;
+ pm->pm_idlepdp = 0;
pm->pm_asid = -1;
TAILQ_INIT(&pm->pm_vmlist);
mutex_init(&pm->pm_lock, MUTEX_DEFAULT, IPL_VM);
- pm->pm_l0table_pa = pmap_alloc_pdp(pm, NULL, true);
+ pm->pm_l0table_pa = pmap_alloc_pdp(pm, NULL, 0, true);
KASSERT(pm->pm_l0table_pa != POOL_PADDR_INVALID);
pm->pm_l0table = (pd_entry_t *)AARCH64_PA_TO_KVA(pm->pm_l0table_pa);
KASSERT(((vaddr_t)pm->pm_l0table & (PAGE_SIZE - 1)) == 0);
@@ -1379,14 +1438,21 @@
wirecount = atomic_add_16_nv(&pg->wire_count, -1);
- if (!do_free_pdp)
+ if (!do_free_pdp) {
+ /*
+ * pm_idlepdp is counted by only pmap_page_protect() with
+ * VM_PROT_NONE. it is not correct because without considering
+ * pmap_enter(), but useful hint to just sweep.
+ */
+ if (wirecount == 1)
+ atomic_inc_uint(&pm->pm_idlepdp);
return false;
+ }
/* if no reference, free pdp */
removed = false;
while (wirecount == 1) {
pd_entry_t *ptep_in_parent, opte;;
-
ptep_in_parent = VM_PAGE_TO_MD(pg)->mdpg_ptep_parent;
if (ptep_in_parent == NULL) {
/* no parent */
@@ -1426,7 +1492,7 @@
_pmap_enter(struct pmap *pm, vaddr_t va, paddr_t pa, vm_prot_t prot,
u_int flags, bool kenter)
{
- struct vm_page *pg, *pdppg, *pdppg0;
+ struct vm_page *pg, *pgs[2], *pdppg, *pdppg0;
struct pv_entry *spv, *opv = NULL;
pd_entry_t pde;
pt_entry_t attr, pte, opte, *ptep;
@@ -1493,6 +1559,13 @@
pm_lock(pm);
+ if (pm->pm_idlepdp >= PDPSWEEP_TRIGGER) {
+ if (_pmap_sweep_pdp(pm) != 0) {
+ /* several L1-L3 page table pages have been freed */
+ aarch64_tlbi_by_asid(pm->pm_asid);
+ }
+ }
+
/*
* traverse L0 -> L1 -> L2 -> L3 table with growing pdp if needed.
*/
@@ -1502,7 +1575,7 @@
pde = l0[idx];
if (!l0pde_valid(pde)) {
/* no need to increment L0 occupancy. L0 page never freed */
- pdppa = pmap_alloc_pdp(pm, &pdppg, flags); /* L1 pdp */
+ pdppa = pmap_alloc_pdp(pm, &pdppg, flags, false); /* L1 pdp */
if (pdppa == POOL_PADDR_INVALID) {
if (flags & PMAP_CANFAIL) {
error = ENOMEM;
@@ -1525,7 +1598,7 @@
if (!l1pde_valid(pde)) {
pdppa0 = pdppa;
pdppg0 = pdppg;
- pdppa = pmap_alloc_pdp(pm, &pdppg, flags); /* L2 pdp */
+ pdppa = pmap_alloc_pdp(pm, &pdppg, flags, false); /* L2 pdp */
if (pdppa == POOL_PADDR_INVALID) {
if (flags & PMAP_CANFAIL) {
error = ENOMEM;
@@ -1549,7 +1622,7 @@
if (!l2pde_valid(pde)) {
pdppa0 = pdppa;
pdppg0 = pdppg;
- pdppa = pmap_alloc_pdp(pm, &pdppg, flags); /* L3 pdp */
+ pdppa = pmap_alloc_pdp(pm, &pdppg, flags, false); /* L3 pdp */
if (pdppa == POOL_PADDR_INVALID) {
if (flags & PMAP_CANFAIL) {
error = ENOMEM;
@@ -1580,8 +1653,9 @@
}
#endif
- if (pg != NULL)
- pmap_pv_lock(VM_PAGE_TO_MD(pg));
+ /* for lock ordering for pg and opg */
+ pgs[0] = pg;
+ pgs[1] = NULL;
/* remap? */
if (l3pte_valid(opte)) {
@@ -1615,14 +1689,32 @@
} else {
need_remove_pv = true;
}
- if (need_remove_pv) {
- opg = PHYS_TO_VM_PAGE(l3pte_pa(opte));
- if (opg != NULL) {
- opv = _pmap_remove_pv(opg, pm, va, opte);
+
+ if (need_remove_pv &&
+ ((opg = PHYS_TO_VM_PAGE(l3pte_pa(opte))) != NULL)) {
+ /* need to lock both pg and opg against deadlock */
+ if (pg < opg) {
+ pgs[0] = pg;
+ pgs[1] = opg;
+ } else {
+ pgs[0] = opg;
+ pgs[1] = pg;
}
+ pmap_pv_lock(VM_PAGE_TO_MD(pgs[0]));
+ pmap_pv_lock(VM_PAGE_TO_MD(pgs[1]));
+ opv = _pmap_remove_pv(opg, pm, va, opte);
+ } else {
+ if (pg != NULL)
+ pmap_pv_lock(VM_PAGE_TO_MD(pg));
}
+ } else {
+ if (pg != NULL)
+ pmap_pv_lock(VM_PAGE_TO_MD(pg));
}
+ if (!l3pte_valid(opte))
+ _pmap_pdp_addref(pm, pdppa, pdppg); /* L3 occupancy++ */
+
/*
* read permission is treated as an access permission internally.
* require to add PROT_READ even if only PROT_WRITE or PROT_EXEC
@@ -1700,17 +1792,16 @@
AARCH64_TLBI_BY_ASID_VA(pm->pm_asid, va, l3only);
}
- if (!l3pte_valid(opte))
- _pmap_pdp_addref(pm, pdppa, pdppg); /* L3 occupancy++ */
-
if (pte & LX_BLKPAG_OS_WIRED) {
PMSTAT_INC_WIRED_COUNT(pm);
}
PMSTAT_INC_RESIDENT_COUNT(pm);
fail1:
- if (pg != NULL)
- pmap_pv_unlock(VM_PAGE_TO_MD(pg));
+ if (pgs[1] != NULL)
+ pmap_pv_unlock(VM_PAGE_TO_MD(pgs[1]));
+ if (pgs[0] != NULL)
+ pmap_pv_unlock(VM_PAGE_TO_MD(pgs[0]));
fail0:
pm_unlock(pm);
diff -r 1fd1263a36f4 -r a822b6d11d61 sys/arch/aarch64/include/asan.h
--- a/sys/arch/aarch64/include/asan.h Mon Apr 08 20:18:14 2019 +0000
+++ b/sys/arch/aarch64/include/asan.h Mon Apr 08 21:18:22 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: asan.h,v 1.5 2019/03/19 16:05:49 ryo Exp $ */
+/* $NetBSD: asan.h,v 1.6 2019/04/08 21:18:22 ryo Exp $ */
/*
* Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -70,7 +70,7 @@
if (__predict_false(__md_early))
pa = (paddr_t)bootpage_alloc();
else
- pa = pmap_alloc_pdp(pmap_kernel(), NULL, false);
+ pa = pmap_alloc_pdp(pmap_kernel(), NULL, 0, false);
return pa;
}
diff -r 1fd1263a36f4 -r a822b6d11d61 sys/arch/aarch64/include/pmap.h
--- a/sys/arch/aarch64/include/pmap.h Mon Apr 08 20:18:14 2019 +0000
+++ b/sys/arch/aarch64/include/pmap.h Mon Apr 08 21:18:22 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.h,v 1.23 2019/03/19 16:45:28 ryo Exp $ */
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