[src/trunk]: src/sys/arch/alpha Keep track of a pmap's PV entries with a list...

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

details:   https://anonhg.NetBSD.org/src/rev/eb941c21a185
branches:  trunk
changeset: 1021440:eb941c21a185
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sun May 30 13:34:21 2021 +0000

description:
Keep track of a pmap's PV entries with a list hanging off the pmap.

diffstat:

 sys/arch/alpha/alpha/pmap.c   |  14 ++++++++++++--
 sys/arch/alpha/include/pmap.h |   7 ++++---
 2 files changed, 16 insertions(+), 5 deletions(-)

diffs (86 lines):

diff -r a19e5b92b961 -r eb941c21a185 sys/arch/alpha/alpha/pmap.c
--- a/sys/arch/alpha/alpha/pmap.c       Sun May 30 13:20:01 2021 +0000
+++ b/sys/arch/alpha/alpha/pmap.c       Sun May 30 13:34:21 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.287 2021/05/30 06:41:19 thorpej Exp $ */
+/* $NetBSD: pmap.c,v 1.288 2021/05/30 13:34:21 thorpej Exp $ */
 
 /*-
  * Copyright (c) 1998, 1999, 2000, 2001, 2007, 2008, 2020
@@ -135,7 +135,7 @@
 
 #include <sys/cdefs.h>                 /* RCS ID & Copyright macro defns */
 
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.287 2021/05/30 06:41:19 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.288 2021/05/30 13:34:21 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1384,6 +1384,7 @@
         */
        memset(pmap_kernel(), 0, sizeof(struct pmap));
        LIST_INIT(&pmap_kernel()->pm_ptpages);
+       LIST_INIT(&pmap_kernel()->pm_pvents);
        atomic_store_relaxed(&pmap_kernel()->pm_count, 1);
        /* Kernel pmap does not have per-CPU info. */
        TAILQ_INSERT_TAIL(&pmap_all_pmaps, pmap_kernel(), pm_list);
@@ -1568,6 +1569,7 @@
        pmap = pool_cache_get(&pmap_pmap_cache, PR_WAITOK);
        memset(pmap, 0, sizeof(*pmap));
        LIST_INIT(&pmap->pm_ptpages);
+       LIST_INIT(&pmap->pm_pvents);
 
        atomic_store_relaxed(&pmap->pm_count, 1);
 
@@ -3278,6 +3280,7 @@
        uintptr_t const attrs = md->pvh_listx & PGA_ATTRS;
        newpv->pv_next = (struct pv_entry *)(md->pvh_listx & ~PGA_ATTRS);
        md->pvh_listx = (uintptr_t)newpv | attrs;
+       LIST_INSERT_HEAD(&pmap->pm_pvents, newpv, pv_link);
 
        if (dolock) {
                mutex_exit(lock);
@@ -3316,8 +3319,15 @@
 
        KASSERT(pv != NULL);
 
+       /*
+        * The page attributes are in the lower 2 bits of the first
+        * PV entry pointer.  Rather than comparing the pointer address
+        * and branching, we just always preserve what might be there
+        * (either attribute bits or zero bits).
+        */
        *pvp = (pv_entry_t)((uintptr_t)pv->pv_next |
                            (((uintptr_t)*pvp) & PGA_ATTRS));
+       LIST_REMOVE(pv, pv_link);
 
        if (dolock) {
                mutex_exit(lock);
diff -r a19e5b92b961 -r eb941c21a185 sys/arch/alpha/include/pmap.h
--- a/sys/arch/alpha/include/pmap.h     Sun May 30 13:20:01 2021 +0000
+++ b/sys/arch/alpha/include/pmap.h     Sun May 30 13:34:21 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.h,v 1.93 2021/05/30 06:41:19 thorpej Exp $ */
+/* $NetBSD: pmap.h,v 1.94 2021/05/30 13:34:21 thorpej Exp $ */
 
 /*-
  * Copyright (c) 1998, 1999, 2000, 2001, 2007 The NetBSD Foundation, Inc.
@@ -151,7 +151,7 @@
        unsigned int            pm_count;       /* [24] reference count */
        unsigned int            __pm_spare0;    /* [28] spare field */
        struct pmap_pagelist    pm_ptpages;     /* [32] list of PT pages */
-       unsigned long           __pm_spare1;    /* [40] spare field */
+       LIST_HEAD(, pv_entry)   pm_pvents;      /* [40] list of PV entries */
        TAILQ_ENTRY(pmap)       pm_list;        /* [48] list of all pmaps */
        /* -- COHERENCY_UNIT boundary -- */
        struct pmap_percpu      pm_percpu[];    /* [64] per-CPU data */
@@ -171,7 +171,8 @@
  * mappings of that page.  An entry is a pv_entry_t, the list is pv_table.
  */
 typedef struct pv_entry {
-       struct pv_entry *pv_next;       /* next pv_entry on list */
+       struct pv_entry *pv_next;       /* next pv_entry on page list */
+       LIST_ENTRY(pv_entry) pv_link;   /* link on owning pmap's list */
        struct pmap     *pv_pmap;       /* pmap where mapping lies */
        vaddr_t         pv_va;          /* virtual address for mapping */
        pt_entry_t      *pv_pte;        /* PTE that maps the VA */