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The pmap code was too generous in the allocation of kva space for

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the pv entries.  This problem has become obvious due to the increase
in the size of the pv entries.  We need to create a more intelligent
policy for pv entry management eventually.
Submitted by:	David Greenman <dg@freebsd.org>
This commit is contained in:
dyson 1997-04-13 03:35:30 +00:00
parent d986da5044
commit 548320010c
2 changed files with 24 additions and 12 deletions
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18
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 1.139 1997/04/07 07:15:52 peter Exp $
* $Id: pmap.c,v 1.140 1997/04/13 01:48:08 dyson Exp $
*/
/*
@ -102,6 +102,7 @@
#include <machine/specialreg.h>
#define PMAP_KEEP_PDIRS
#define PMAP_SHPGPERPROC 200
#if defined(DIAGNOSTIC)
#define PMAP_DIAGNOSTIC
@ -1429,17 +1430,22 @@ pmap_alloc_pv_entry()
/*
* init the pv_entry allocation system
*/
#define PVSPERPAGE 64
void
init_pv_entries(npg)
int npg;
{
/*
* allocate enough kvm space for PVSPERPAGE entries per page (lots)
* kvm space is fairly cheap, be generous!!! (the system can panic if
* this is too small.)
* Allocate enough kvm space for one entry per page, and
* each process having PMAP_SHPGPERPROC pages shared with other
* processes. (The system can panic if this is too small, but also
* can fail on bootup if this is too big.)
* XXX The pv management mechanism needs to be fixed so that systems
* with lots of shared mappings amongst lots of processes will still
* work. The fix will likely be that once we run out of pv entries
* we will free other entries (and the associated mappings), with
* some policy yet to be determined.
*/
npvvapg = ((npg * PVSPERPAGE) * sizeof(struct pv_entry)
npvvapg = ((PMAP_SHPGPERPROC * maxproc + npg) * sizeof(struct pv_entry)
+ PAGE_SIZE - 1) / PAGE_SIZE;
pvva = kmem_alloc_pageable(kernel_map, npvvapg * PAGE_SIZE);
/*

18
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 1.139 1997/04/07 07:15:52 peter Exp $
* $Id: pmap.c,v 1.140 1997/04/13 01:48:08 dyson Exp $
*/
/*
@ -102,6 +102,7 @@
#include <machine/specialreg.h>
#define PMAP_KEEP_PDIRS
#define PMAP_SHPGPERPROC 200
#if defined(DIAGNOSTIC)
#define PMAP_DIAGNOSTIC
@ -1429,17 +1430,22 @@ pmap_alloc_pv_entry()
/*
* init the pv_entry allocation system
*/
#define PVSPERPAGE 64
void
init_pv_entries(npg)
int npg;
{
/*
* allocate enough kvm space for PVSPERPAGE entries per page (lots)
* kvm space is fairly cheap, be generous!!! (the system can panic if
* this is too small.)
* Allocate enough kvm space for one entry per page, and
* each process having PMAP_SHPGPERPROC pages shared with other
* processes. (The system can panic if this is too small, but also
* can fail on bootup if this is too big.)
* XXX The pv management mechanism needs to be fixed so that systems
* with lots of shared mappings amongst lots of processes will still
* work. The fix will likely be that once we run out of pv entries
* we will free other entries (and the associated mappings), with
* some policy yet to be determined.
*/
npvvapg = ((npg * PVSPERPAGE) * sizeof(struct pv_entry)
npvvapg = ((PMAP_SHPGPERPROC * maxproc + npg) * sizeof(struct pv_entry)
+ PAGE_SIZE - 1) / PAGE_SIZE;
pvva = kmem_alloc_pageable(kernel_map, npvvapg * PAGE_SIZE);
/*