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Two changes to pmap_remove_all:

Browse Source 
1. Switch to pmap_TLB_invalidate from invltlb, eliminating a full TLB
flush where a single-page flush suffices.  (Also, this eliminates some
unnecessary IPIs.)

2. Use "loadandclear" to update the pte, eliminating a race condition
on SMPs.

Change #2 should be committed to -STABLE.
This commit is contained in:
Alan Cox 1999-04-06 04:52:27 +00:00
parent 5ef4895832
commit 47b9dbd431
2 changed files with 10 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
sys/amd64/amd64/pmap.c
View File

@ -39,7 +39,7 @@
* SUCH DAMAGE.
*
* from: @(#)pmap.c 7.7 (Berkeley) 5/12/91
* $Id: pmap.c,v 1.226 1999/04/02 17:59:38 alc Exp $
* $Id: pmap.c,v 1.227 1999/04/05 19:38:28 julian Exp $
*/
/*
@ -1964,10 +1964,8 @@ pmap_remove_all(pa)
register pv_entry_t pv;
pv_table_t *ppv;
register unsigned *pte, tpte;
int update_needed;
int s;
update_needed = 0;
#if defined(PMAP_DIAGNOSTIC)
/*
* XXX this makes pmap_page_protect(NONE) illegal for non-managed
@ -1981,12 +1979,11 @@ pmap_remove_all(pa)
s = splvm();
ppv = pa_to_pvh(pa);
while ((pv = TAILQ_FIRST(&ppv->pv_list)) != NULL) {
pte = pmap_pte_quick(pv->pv_pmap, pv->pv_va);
pv->pv_pmap->pm_stats.resident_count--;
tpte = *pte;
*pte = 0;
pte = pmap_pte_quick(pv->pv_pmap, pv->pv_va);
tpte = loadandclear(pte);
if (tpte & PG_W)
pv->pv_pmap->pm_stats.wired_count--;
@ -2007,15 +2004,7 @@ pmap_remove_all(pa)
if (pmap_track_modified(pv->pv_va))
vm_page_dirty(ppv->pv_vm_page);
}
#ifdef SMP
update_needed = 1;
#else
if (!update_needed &&
((!curproc || (vmspace_pmap(curproc->p_vmspace) == pv->pv_pmap)) ||
(pv->pv_pmap == kernel_pmap))) {
update_needed = 1;
}
#endif
pmap_TLB_invalidate(pv->pv_pmap, pv->pv_va);
TAILQ_REMOVE(&pv->pv_pmap->pm_pvlist, pv, pv_plist);
TAILQ_REMOVE(&ppv->pv_list, pv, pv_list);
@ -2026,11 +2015,7 @@ pmap_remove_all(pa)
vm_page_flag_clear(ppv->pv_vm_page, PG_MAPPED | PG_WRITEABLE);
if (update_needed)
invltlb();
splx(s);
return;
}
/*

25
sys/i386/i386/pmap.c
View File

@ -39,7 +39,7 @@
* SUCH DAMAGE.
*
* from: @(#)pmap.c 7.7 (Berkeley) 5/12/91
* $Id: pmap.c,v 1.226 1999/04/02 17:59:38 alc Exp $
* $Id: pmap.c,v 1.227 1999/04/05 19:38:28 julian Exp $
*/
/*
@ -1964,10 +1964,8 @@ pmap_remove_all(pa)
register pv_entry_t pv;
pv_table_t *ppv;
register unsigned *pte, tpte;
int update_needed;
int s;
update_needed = 0;
#if defined(PMAP_DIAGNOSTIC)
/*
* XXX this makes pmap_page_protect(NONE) illegal for non-managed
@ -1981,12 +1979,11 @@ pmap_remove_all(pa)
s = splvm();
ppv = pa_to_pvh(pa);
while ((pv = TAILQ_FIRST(&ppv->pv_list)) != NULL) {
pte = pmap_pte_quick(pv->pv_pmap, pv->pv_va);
pv->pv_pmap->pm_stats.resident_count--;
tpte = *pte;
*pte = 0;
pte = pmap_pte_quick(pv->pv_pmap, pv->pv_va);
tpte = loadandclear(pte);
if (tpte & PG_W)
pv->pv_pmap->pm_stats.wired_count--;
@ -2007,15 +2004,7 @@ pmap_remove_all(pa)
if (pmap_track_modified(pv->pv_va))
vm_page_dirty(ppv->pv_vm_page);
}
#ifdef SMP
update_needed = 1;
#else
if (!update_needed &&
((!curproc || (vmspace_pmap(curproc->p_vmspace) == pv->pv_pmap)) ||
(pv->pv_pmap == kernel_pmap))) {
update_needed = 1;
}
#endif
pmap_TLB_invalidate(pv->pv_pmap, pv->pv_va);
TAILQ_REMOVE(&pv->pv_pmap->pm_pvlist, pv, pv_plist);
TAILQ_REMOVE(&ppv->pv_list, pv, pv_list);
@ -2026,11 +2015,7 @@ pmap_remove_all(pa)
vm_page_flag_clear(ppv->pv_vm_page, PG_MAPPED | PG_WRITEABLE);
if (update_needed)
invltlb();
splx(s);
return;
}
/*