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[src/trunk]: src/sys/arch/alpha/alpha Use a pool cache for L1 PT pages. When...
details: https://anonhg.NetBSD.org/src/rev/817020807293
branches: trunk
changeset: 500166:817020807293
user: thorpej <thorpej%NetBSD.org@localhost>
date: Thu Dec 07 05:59:07 2000 +0000
description:
Use a pool cache for L1 PT pages. When we can allocate a cached,
constructed L1 PT page, this saves us from having to copy the kernel
L1 PTEs into the user L1 PT page at fork time (it's already set up).
A simple test shows a 1 second improvement of a rapid fork/exit operation
10000 times on a 533MHz 21164A (12s to 11s).
diffstat:
sys/arch/alpha/alpha/pmap.c | 143 ++++++++++++++++++++++++++++++++-----------
1 files changed, 106 insertions(+), 37 deletions(-)
diffs (234 lines):
diff -r 147928e628c2 -r 817020807293 sys/arch/alpha/alpha/pmap.c
--- a/sys/arch/alpha/alpha/pmap.c Thu Dec 07 05:45:57 2000 +0000
+++ b/sys/arch/alpha/alpha/pmap.c Thu Dec 07 05:59:07 2000 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.151 2000/11/24 22:41:38 chs Exp $ */
+/* $NetBSD: pmap.c,v 1.152 2000/12/07 05:59:07 thorpej Exp $ */
/*-
* Copyright (c) 1998, 1999, 2000 The NetBSD Foundation, Inc.
@@ -156,7 +156,7 @@
#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.151 2000/11/24 22:41:38 chs Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.152 2000/12/07 05:59:07 thorpej Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -277,6 +277,8 @@
* The pools from which pmap structures and sub-structures are allocated.
*/
struct pool pmap_pmap_pool;
+struct pool pmap_l1pt_pool;
+struct pool_cache pmap_l1pt_cache;
struct pool pmap_asn_pool;
struct pool pmap_asngen_pool;
struct pool pmap_pv_pool;
@@ -515,6 +517,11 @@
void pmap_l2pt_delref(pmap_t, pt_entry_t *, pt_entry_t *, long);
void pmap_l1pt_delref(pmap_t, pt_entry_t *, long);
+void *pmap_l1pt_alloc(unsigned long, int, int);
+void pmap_l1pt_free(void *, unsigned long, int);
+
+int pmap_l1pt_ctor(void *, void *, int);
+
/*
* PV table management functions.
*/
@@ -945,6 +952,10 @@
pmap_ncpuids = ncpuids;
pool_init(&pmap_pmap_pool, sizeof(struct pmap), 0, 0, 0, "pmappl",
0, pool_page_alloc_nointr, pool_page_free_nointr, M_VMPMAP);
+ pool_init(&pmap_l1pt_pool, PAGE_SIZE, 0, 0, 0, "l1ptpl",
+ 0, pmap_l1pt_alloc, pmap_l1pt_free, M_VMPMAP);
+ pool_cache_init(&pmap_l1pt_cache, &pmap_l1pt_pool, pmap_l1pt_ctor,
+ NULL, NULL);
pool_init(&pmap_asn_pool, pmap_ncpuids * sizeof(u_int), 0, 0, 0,
"pmasnpl",
0, pool_page_alloc_nointr, pool_page_free_nointr, M_VMPMAP);
@@ -3274,7 +3285,13 @@
struct pv_head *pvh;
paddr_t pa;
- pg = uvm_pagealloc(NULL, 0, NULL, UVM_PGA_USERESERVE|UVM_PGA_ZERO);
+ /*
+ * Don't ask for a zero'd page in the L1PT case -- we will
+ * properly initialize it in the constructor.
+ */
+
+ pg = uvm_pagealloc(NULL, 0, NULL, usage == PGU_L1PT ?
+ UVM_PGA_USERESERVE : UVM_PGA_USERESERVE|UVM_PGA_ZERO);
if (pg != NULL) {
pa = VM_PAGE_TO_PHYS(pg);
@@ -3445,8 +3462,9 @@
l1idx = l1pte_index(va);
+ simple_lock(&pmap_all_pmaps_slock);
+
/* Update all the user pmaps. */
- simple_lock(&pmap_all_pmaps_slock);
for (pm = TAILQ_FIRST(&pmap_all_pmaps);
pm != NULL; pm = TAILQ_NEXT(pm, pm_list)) {
/* Skip the kernel pmap. */
@@ -3461,6 +3479,10 @@
pm->pm_lev1map[l1idx] = pte;
PMAP_UNLOCK(pm);
}
+
+ /* Invalidate the L1 PT cache. */
+ pool_cache_invalidate(&pmap_l1pt_cache);
+
simple_unlock(&pmap_all_pmaps_slock);
}
@@ -3504,9 +3526,7 @@
int
pmap_lev1map_create(pmap_t pmap, long cpu_id)
{
- paddr_t ptpa;
- pt_entry_t pte;
- int i;
+ pt_entry_t *l1pt;
#ifdef DIAGNOSTIC
if (pmap == pmap_kernel())
@@ -3516,32 +3536,11 @@
panic("pmap_lev1map_create: pmap uses non-reserved ASN");
#endif
- /*
- * Allocate a page for the level 1 table.
- */
- if (pmap_physpage_alloc(PGU_L1PT, &ptpa) == FALSE) {
- /*
- * Yow! No free pages! Try to steal a PT page from
- * another pmap!
- */
- if (pmap_ptpage_steal(pmap, PGU_L1PT, &ptpa) == FALSE)
- return (KERN_RESOURCE_SHORTAGE);
- }
- pmap->pm_lev1map = (pt_entry_t *) ALPHA_PHYS_TO_K0SEG(ptpa);
-
- /*
- * Initialize the new level 1 table by copying the
- * kernel mappings into it.
- */
- for (i = l1pte_index(VM_MIN_KERNEL_ADDRESS);
- i <= l1pte_index(VM_MAX_KERNEL_ADDRESS); i++)
- pmap->pm_lev1map[i] = kernel_lev1map[i];
-
- /*
- * Now, map the new virtual page table. NOTE: NO ASM!
- */
- pte = ((ptpa >> PGSHIFT) << PG_SHIFT) | PG_V | PG_KRE | PG_KWE;
- pmap->pm_lev1map[l1pte_index(VPTBASE)] = pte;
+ l1pt = pool_cache_get(&pmap_l1pt_cache, PR_NOWAIT);
+ if (l1pt == NULL)
+ return (KERN_RESOURCE_SHORTAGE);
+
+ pmap->pm_lev1map = l1pt;
/*
* The page table base has changed; if the pmap was active,
@@ -3564,15 +3563,13 @@
void
pmap_lev1map_destroy(pmap_t pmap, long cpu_id)
{
- paddr_t ptpa;
+ pt_entry_t *l1pt = pmap->pm_lev1map;
#ifdef DIAGNOSTIC
if (pmap == pmap_kernel())
panic("pmap_lev1map_destroy: got kernel pmap");
#endif
- ptpa = ALPHA_K0SEG_TO_PHYS((vaddr_t)pmap->pm_lev1map);
-
/*
* Go back to referencing the global kernel_lev1map.
*/
@@ -3603,7 +3600,79 @@
/*
* Free the old level 1 page table page.
*/
- pmap_physpage_free(ptpa);
+ pool_cache_put(&pmap_l1pt_cache, l1pt);
+}
+
+/*
+ * pmap_l1pt_ctor:
+ *
+ * Pool cache constructor for L1 PT pages.
+ */
+int
+pmap_l1pt_ctor(void *arg, void *object, int flags)
+{
+ pt_entry_t *l1pt = object, pte;
+ int i;
+
+ /*
+ * Initialize the new level 1 table by zeroing the
+ * user portion and copying the kernel mappings into
+ * the kernel portion.
+ */
+ for (i = 0; i < l1pte_index(VM_MIN_KERNEL_ADDRESS); i++)
+ l1pt[i] = 0;
+
+ for (i = l1pte_index(VM_MIN_KERNEL_ADDRESS);
+ i <= l1pte_index(VM_MAX_KERNEL_ADDRESS); i++)
+ l1pt[i] = kernel_lev1map[i];
+
+ /*
+ * Now, map the new virtual page table. NOTE: NO ASM!
+ */
+ pte = ((ALPHA_K0SEG_TO_PHYS((vaddr_t) l1pt) >> PGSHIFT) << PG_SHIFT) |
+ PG_V | PG_KRE | PG_KWE;
+ l1pt[l1pte_index(VPTBASE)] = pte;
+
+ return (0);
+}
+
+/*
+ * pmap_l1pt_alloc:
+ *
+ * Page alloctor for L1 PT pages.
+ */
+void *
+pmap_l1pt_alloc(unsigned long sz, int flags, int mtype)
+{
+ paddr_t ptpa;
+
+ /*
+ * Attempt to allocate a free page.
+ */
+ if (pmap_physpage_alloc(PGU_L1PT, &ptpa) == FALSE) {
+#if 0
+ /*
+ * Yow! No free pages! Try to steal a PT page from
+ * another pmap!
+ */
+ if (pmap_ptpage_steal(pmap, PGU_L1PT, &ptpa) == FALSE)
+#endif
+ return (NULL);
+ }
+
+ return ((void *) ALPHA_PHYS_TO_K0SEG(ptpa));
+}
+
+/*
+ * pmap_l1pt_free:
+ *
+ * Page freer for L1 PT pages.
+ */
+void
+pmap_l1pt_free(void *v, unsigned long sz, int mtype)
+{
+
+ pmap_physpage_free(ALPHA_K0SEG_TO_PHYS((vaddr_t) v));
}
/*
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