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The target page of pmap_zero_page(), pmap_pageidlezero(), and 

pmap_copy_page() will never have any mappings.  Therefore, it
is unnecessary to do a cache clean for that page.

Add assertions in #ifdef DEBUG that assert this invariant.

This shaves some cycles off the frequently-called pmap_zero_page()
and pmap_copy_page() (no need to look up the dst page's vm_page
structure, and one less function call to clean the page).
This commit is contained in:
thorpej 2002-03-25 17:33:26 +00:00
parent d1f348c04d
commit a2d8f71d01
1 changed files with 30 additions and 31 deletions
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61
sys/arch/arm/arm32/pmap.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: pmap.c,v 1.70 2002/03/25 04:51:20 thorpej Exp $ */
/* $NetBSD: pmap.c,v 1.71 2002/03/25 17:33:26 thorpej Exp $ */
/*
* Copyright (c) 2002 Wasabi Systems, Inc.
@ -143,7 +143,7 @@
#include <machine/param.h>
#include <arm/arm32/katelib.h>
__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.70 2002/03/25 04:51:20 thorpej Exp $");
__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.71 2002/03/25 17:33:26 thorpej Exp $");
#ifdef PMAP_DEBUG
#define PDEBUG(_lev_,_stat_) \
if (pmap_debug_level >= (_lev_)) \
@ -1819,14 +1819,13 @@ void
pmap_zero_page(phys)
paddr_t phys;
{
struct vm_page *pg;
#ifdef DEBUG
struct vm_page *pg = PHYS_TO_VM_PAGE(phys);
if (pg->mdpage.pvh_list != NULL)
panic("pmap_zero_page: page has mappings");
#endif
/* Get an entry for this page, and clean it it. */
pg = PHYS_TO_VM_PAGE(phys);
simple_lock(&pg->mdpage.pvh_slock);
pmap_clean_page(pg->mdpage.pvh_list, FALSE);
simple_unlock(&pg->mdpage.pvh_slock);
/*
* Hook in the page, zero it, and purge the cache for that
* zeroed page. Invalidate the TLB as needed.
@ -1846,17 +1845,16 @@ pmap_zero_page(phys)
*/
boolean_t
pmap_pageidlezero(phys)
paddr_t phys;
paddr_t phys;
{
int i, *ptr;
boolean_t rv = TRUE;
#ifdef DIAGNOSTIC
#ifdef DEBUG
struct vm_page *pg;
pg = PHYS_TO_VM_PAGE(phys);
if (pg->mdpage.pvh_list != NULL)
panic("pmap_pageidlezero: zeroing mapped page\n");
panic("pmap_pageidlezero: page has mappings");
#endif
/*
@ -1899,38 +1897,39 @@ pmap_pageidlezero(phys)
* pmap_zero_page also applies here.
*/
void
pmap_copy_page(src, dest)
pmap_copy_page(src, dst)
paddr_t src;
paddr_t dest;
paddr_t dst;
{
struct vm_page *src_pg, *dest_pg;
boolean_t cleanedcache;
/* Get PV entries for the pages, and clean them if needed. */
src_pg = PHYS_TO_VM_PAGE(src);
simple_lock(&src_pg->mdpage.pvh_slock);
cleanedcache = pmap_clean_page(src_pg->mdpage.pvh_list, TRUE);
simple_unlock(&src_pg->mdpage.pvh_slock);
struct vm_page *src_pg = PHYS_TO_VM_PAGE(src);
#ifdef DEBUG
struct vm_page *dst_pg = PHYS_TO_VM_PAGE(dst);
if (dst_pg->mdpage.pvh_list != NULL)
panic("pmap_copy_page: dst page has mappings");
#endif
/*
* Clean the source page. Hold the source page's lock for
* the duration of the copy so that no other mappings can
* be created while we have a potentially aliased mapping.
*/
simple_lock(&src_pg->mdpage.pvh_slock);
(void) pmap_clean_page(src_pg->mdpage.pvh_list, TRUE);
if (cleanedcache == 0) {
dest_pg = PHYS_TO_VM_PAGE(dest);
simple_lock(&dest_pg->mdpage.pvh_slock);
pmap_clean_page(dest_pg->mdpage.pvh_list, FALSE);
simple_unlock(&dest_pg->mdpage.pvh_slock);
}
/*
* Map the pages into the page hook points, copy them, and purge
* the cache for the appropriate page. Invalidate the TLB
* as required.
*/
*csrc_pte = L2_PTE(src & PG_FRAME, AP_KR);
*cdst_pte = L2_PTE(dest & PG_FRAME, AP_KRW);
*cdst_pte = L2_PTE(dst & PG_FRAME, AP_KRW);
cpu_tlb_flushD_SE(csrcp);
cpu_tlb_flushD_SE(cdstp);
cpu_cpwait();
bcopy_page(csrcp, cdstp);
cpu_dcache_inv_range(csrcp, NBPG);
simple_unlock(&src_pg->mdpage.pvh_slock); /* cache is safe again */
cpu_dcache_wbinv_range(cdstp, NBPG);
}