Author: raj
Date: Mon Aug 19 14:56:17 2013
New Revision: 254531
URL: http://svnweb.freebsd.org/changeset/base/254531
Log:
Simplify pv_entry removal or ARMv6/v7:
- PGA_WRITEABLE indicates that there *might be* a writable mapping for the
particular page, so to avoid frequent sweeping of the pv_entries whenever
pmap_nuke_pv(), pmap_modify_pv(), etc. is called, it is sufficient to
clear that flag if there are no managed mappings for that page anymore
(notice that only pmap_enter is authorized to set this flag).
- Avoid redundant checking for PVF_WIRED flag when this flag cannot be set
anyway.
- Clear PGA_WRITEABLE only once for each vm_page instead of multiple,
redundant clearing it in loop when there are no writeable mappings
to that page anymore.
Submitted by: Zbigniew Bodek <z...@semihalf.com>
Reviewed by: gber
Sponsored by: The FreeBSD Foundation, Semihalf
Modified:
head/sys/arm/arm/pmap-v6.c
Modified: head/sys/arm/arm/pmap-v6.c
==============================================================================
--- head/sys/arm/arm/pmap-v6.c Mon Aug 19 14:42:39 2013 (r254530)
+++ head/sys/arm/arm/pmap-v6.c Mon Aug 19 14:56:17 2013 (r254531)
@@ -1072,39 +1072,22 @@ pmap_set_prot(pt_entry_t *ptep, vm_prot_
* => caller should NOT adjust pmap's wire_count
* => we return the removed pve
*/
-
-static void
-pmap_nuke_pv(struct vm_page *m, pmap_t pmap, struct pv_entry *pve)
-{
-
- rw_assert(&pvh_global_lock, RA_WLOCKED);
- PMAP_ASSERT_LOCKED(pmap);
-
- TAILQ_REMOVE(&m->md.pv_list, pve, pv_list);
-
- if (pve->pv_flags & PVF_WIRED)
- --pmap->pm_stats.wired_count;
-
- if (pve->pv_flags & PVF_WRITE) {
- TAILQ_FOREACH(pve, &m->md.pv_list, pv_list)
- if (pve->pv_flags & PVF_WRITE)
- break;
- if (!pve) {
- vm_page_aflag_clear(m, PGA_WRITEABLE);
- }
- }
-}
-
static struct pv_entry *
pmap_remove_pv(struct vm_page *m, pmap_t pmap, vm_offset_t va)
{
struct pv_entry *pve;
rw_assert(&pvh_global_lock, RA_WLOCKED);
+ PMAP_ASSERT_LOCKED(pmap);
pve = pmap_find_pv(m, pmap, va); /* find corresponding pve */
- if (pve != NULL)
- pmap_nuke_pv(m, pmap, pve);
+ if (pve != NULL) {
+ TAILQ_REMOVE(&m->md.pv_list, pve, pv_list);
+ if (pve->pv_flags & PVF_WIRED)
+ --pmap->pm_stats.wired_count;
+ }
+ if (TAILQ_EMPTY(&m->md.pv_list))
+ vm_page_aflag_clear(m, PGA_WRITEABLE);
return(pve); /* return removed pve */
}
@@ -1143,14 +1126,6 @@ pmap_modify_pv(struct vm_page *m, pmap_t
else
--pmap->pm_stats.wired_count;
}
- if ((oflags & PVF_WRITE) && !(flags & PVF_WRITE)) {
- TAILQ_FOREACH(npv, &m->md.pv_list, pv_list) {
- if (npv->pv_flags & PVF_WRITE)
- break;
- }
- if (!npv)
- vm_page_aflag_clear(m, PGA_WRITEABLE);
- }
return (oflags);
}
@@ -2062,7 +2037,9 @@ pmap_remove_pages(pmap_t pmap)
pv_entry_count--;
pmap->pm_stats.resident_count--;
pc->pc_map[field] |= bitmask;
- pmap_nuke_pv(m, pmap, pv);
+ TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
+ if (TAILQ_EMPTY(&m->md.pv_list))
+ vm_page_aflag_clear(m, PGA_WRITEABLE);
pmap_free_l2_bucket(pmap, l2b, 1);
}
}
@@ -2458,7 +2435,9 @@ pmap_remove_all(vm_page_t m)
PTE_SYNC(ptep);
pmap_free_l2_bucket(pmap, l2b, 1);
pmap->pm_stats.resident_count--;
- pmap_nuke_pv(m, pmap, pv);
+ TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
+ if (pv->pv_flags & PVF_WIRED)
+ pmap->pm_stats.wired_count--;
pmap_free_pv_entry(pmap, pv);
PMAP_UNLOCK(pmap);
}
@@ -2469,6 +2448,7 @@ pmap_remove_all(vm_page_t m)
else
cpu_tlb_flushD();
}
+ vm_page_aflag_clear(m, PGA_WRITEABLE);
rw_wunlock(&pvh_global_lock);
}
@@ -3338,7 +3318,9 @@ pmap_pv_reclaim(pmap_t locked_pmap)
"va %x pte %x", va, *ptep));
*ptep = 0;
PTE_SYNC(ptep);
- pmap_nuke_pv(m, pmap, pv);
+ TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
+ if (TAILQ_EMPTY(&m->md.pv_list))
+ vm_page_aflag_clear(m, PGA_WRITEABLE);
pc->pc_map[field] |= 1UL << bit;
freed++;
}
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