[src/trunk]: src/sys/uvm uvm_fault: Clarify when to wire what.

[uebayasi <uebayasi%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/0495cc11b726
branches:  trunk
changeset: 751349:0495cc11b726
user:      uebayasi <uebayasi%NetBSD.org@localhost>
date:      Mon Feb 01 10:22:40 2010 +0000

description:
uvm_fault: Clarify when to wire what.

diffstat:

 sys/uvm/uvm_fault.c |  38 +++++++++++++++++++++-----------------
 1 files changed, 21 insertions(+), 17 deletions(-)

diffs (116 lines):

diff -r ea3d175bd129 -r 0495cc11b726 sys/uvm/uvm_fault.c
--- a/sys/uvm/uvm_fault.c       Mon Feb 01 09:56:58 2010 +0000
+++ b/sys/uvm/uvm_fault.c       Mon Feb 01 10:22:40 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_fault.c,v 1.145 2010/02/01 09:18:41 uebayasi Exp $ */
+/*     $NetBSD: uvm_fault.c,v 1.146 2010/02/01 10:22:40 uebayasi Exp $ */
 
 /*
  *
@@ -39,7 +39,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_fault.c,v 1.145 2010/02/01 09:18:41 uebayasi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_fault.c,v 1.146 2010/02/01 10:22:40 uebayasi Exp $");
 
 #include "opt_uvmhist.h"
 
@@ -695,9 +695,9 @@
 struct uvm_faultctx {
        vm_prot_t access_type;
        vm_prot_t enter_prot;
-       bool wired;
+       bool wire_mapping;
        bool narrow;
-       bool wire_fault;
+       bool wire_paging;
        bool maxprot;
        bool cow_now;
        int npages;
@@ -731,7 +731,14 @@
        struct uvm_faultinfo ufi;
        struct uvm_faultctx flt = {
                .access_type = access_type,
-               .wire_fault = (fault_flag & UVM_FAULT_WIRE) != 0,
+
+               /* don't look for neighborhood * pages on "wire" fault */
+               .narrow = (fault_flag & UVM_FAULT_WIRE) != 0,
+
+               /* "wire" fault causes wiring of both mapping and paging */
+               .wire_mapping = (fault_flag & UVM_FAULT_WIRE) != 0,
+               .wire_paging = (fault_flag & UVM_FAULT_WIRE) != 0,
+
                .maxprot = (fault_flag & UVM_FAULT_MAXPROT) != 0,
        };
        struct vm_anon *anons_store[UVM_MAXRANGE], **anons;
@@ -751,11 +758,6 @@
        ufi.orig_map = orig_map;
        ufi.orig_rvaddr = trunc_page(vaddr);
        ufi.orig_size = PAGE_SIZE;      /* can't get any smaller than this */
-       if (flt.wire_fault)
-               flt.narrow = true;      /* don't look for neighborhood
-                                        * pages on wire */
-       else
-               flt.narrow = false;     /* normal fault */
 
        error = ERESTART;
        while (error == ERESTART) {
@@ -835,8 +837,10 @@
         */
 
        flt->enter_prot = ufi->entry->protection;
-       flt->wired = VM_MAPENT_ISWIRED(ufi->entry) || flt->wire_fault;
-       if (flt->wired) {
+       if (VM_MAPENT_ISWIRED(ufi->entry))
+               flt->wire_mapping = true;
+
+       if (flt->wire_mapping) {
                flt->access_type = flt->enter_prot; /* full access for wired */
                flt->cow_now = (check_prot & VM_PROT_WRITE) != 0;
        } else {
@@ -1252,7 +1256,7 @@
                    VM_PAGE_TO_PHYS(curpg),
                    readonly ?  flt->enter_prot & ~VM_PROT_WRITE :
                    flt->enter_prot & MASK(ufi->entry),
-                   PMAP_CANFAIL | (flt->wired ? PMAP_WIRED : 0));
+                   PMAP_CANFAIL | (flt->wire_mapping ? PMAP_WIRED : 0));
 
                /*
                 * NOTE: page can't be PG_WANTED or PG_RELEASED because we've
@@ -1528,7 +1532,7 @@
        UVMHIST_LOG(maphist, "  MAPPING: anon: pm=0x%x, va=0x%x, pg=0x%x",
            ufi->orig_map->pmap, ufi->orig_rvaddr, pg, 0);
        if (pmap_enter(ufi->orig_map->pmap, ufi->orig_rvaddr, VM_PAGE_TO_PHYS(pg),
-           flt->enter_prot, flt->access_type | PMAP_CANFAIL | (flt->wired ? PMAP_WIRED : 0))
+           flt->enter_prot, flt->access_type | PMAP_CANFAIL | (flt->wire_mapping ? PMAP_WIRED : 0))
            != 0) {
 
                /*
@@ -1559,7 +1563,7 @@
         */
 
        mutex_enter(&uvm_pageqlock);
-       if (flt->wire_fault) {
+       if (flt->wire_paging) {
                uvm_pagewire(pg);
 
                /*
@@ -1929,7 +1933,7 @@
                (pg->flags & PG_RDONLY) == 0);
        if (pmap_enter(ufi->orig_map->pmap, ufi->orig_rvaddr, VM_PAGE_TO_PHYS(pg),
            pg->flags & PG_RDONLY ? flt->enter_prot & ~VM_PROT_WRITE : flt->enter_prot,
-           flt->access_type | PMAP_CANFAIL | (flt->wired ? PMAP_WIRED : 0)) != 0) {
+           flt->access_type | PMAP_CANFAIL | (flt->wire_mapping ? PMAP_WIRED : 0)) != 0) {
 
                /*
                 * No need to undo what we did; we can simply think of
@@ -1964,7 +1968,7 @@
        }
 
        mutex_enter(&uvm_pageqlock);
-       if (flt->wire_fault) {
+       if (flt->wire_paging) {
                uvm_pagewire(pg);
                if (pg->pqflags & PQ_AOBJ) {