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Code Issues Releases Activity

Introduce pmap_remove_l3_range() and use it in two places:

Browse Source 
(1) pmap_remove(), where it eliminates redundant TLB invalidations by
pmap_remove() and pmap_remove_l3(), and (2) pmap_enter_l2(), where it may
optimize the TLB invalidations by batching them.

Reviewed by:	markj
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D12725
This commit is contained in:
Alan Cox 2019-06-22 16:26:38 +00:00
parent 6ab631e856
commit 36c5a4cb3f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=349290
1 changed files with 83 additions and 33 deletions
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116
sys/arm64/arm64/pmap.c
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@ -2509,6 +2509,82 @@ pmap_remove_l3(pmap_t pmap, pt_entry_t *l3, vm_offset_t va,
return (pmap_unuse_pt(pmap, va, l2e, free));
}
/*
* Remove the specified range of addresses from the L3 page table that is
* identified by the given L2 entry.
*/
static void
pmap_remove_l3_range(pmap_t pmap, pd_entry_t l2e, vm_offset_t sva,
vm_offset_t eva, struct spglist *free, struct rwlock **lockp)
{
struct md_page *pvh;
struct rwlock *new_lock;
pt_entry_t *l3, old_l3;
vm_offset_t va;
vm_page_t m;
PMAP_LOCK_ASSERT(pmap, MA_OWNED);
KASSERT(rounddown2(sva, L2_SIZE) + L2_SIZE == roundup2(eva, L2_SIZE),
("pmap_remove_l3_range: range crosses an L3 page table boundary"));
va = eva;
for (l3 = pmap_l2_to_l3(&l2e, sva); sva != eva; l3++, sva += L3_SIZE) {
if (!pmap_l3_valid(pmap_load(l3))) {
if (va != eva) {
pmap_invalidate_range(pmap, va, sva);
va = eva;
}
continue;
}
old_l3 = pmap_load_clear(l3);
if ((old_l3 & ATTR_SW_WIRED) != 0)
pmap->pm_stats.wired_count--;
pmap_resident_count_dec(pmap, 1);
if ((old_l3 & ATTR_SW_MANAGED) != 0) {
m = PHYS_TO_VM_PAGE(old_l3 & ~ATTR_MASK);
if (pmap_page_dirty(old_l3))
vm_page_dirty(m);
if ((old_l3 & ATTR_AF) != 0)
vm_page_aflag_set(m, PGA_REFERENCED);
new_lock = PHYS_TO_PV_LIST_LOCK(VM_PAGE_TO_PHYS(m));
if (new_lock != *lockp) {
if (*lockp != NULL) {
/*
* Pending TLB invalidations must be
* performed before the PV list lock is
* released. Otherwise, a concurrent
* pmap_remove_all() on a physical page
* could return while a stale TLB entry
* still provides access to that page.
*/
if (va != eva) {
pmap_invalidate_range(pmap, va,
sva);
va = eva;
}
rw_wunlock(*lockp);
}
*lockp = new_lock;
rw_wlock(*lockp);
}
pmap_pvh_free(&m->md, pmap, sva);
if (TAILQ_EMPTY(&m->md.pv_list) &&
(m->flags & PG_FICTITIOUS) == 0) {
pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
if (TAILQ_EMPTY(&pvh->pv_list))
vm_page_aflag_clear(m, PGA_WRITEABLE);
}
}
if (va == eva)
va = sva;
if (pmap_unuse_pt(pmap, sva, l2e, free)) {
sva += L3_SIZE;
break;
}
}
if (va != eva)
pmap_invalidate_range(pmap, va, sva);
}
/*
* Remove the given range of addresses from the specified map.
*
@ -2519,9 +2595,9 @@ void
pmap_remove(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
{
struct rwlock *lock;
vm_offset_t va, va_next;
vm_offset_t va_next;
pd_entry_t *l0, *l1, *l2;
pt_entry_t l3_paddr, *l3;
pt_entry_t l3_paddr;
struct spglist free;
/*
@ -2594,28 +2670,8 @@ pmap_remove(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
if (va_next > eva)
va_next = eva;
va = va_next;
for (l3 = pmap_l2_to_l3(l2, sva); sva != va_next; l3++,
sva += L3_SIZE) {
if (l3 == NULL)
panic("l3 == NULL");
if (pmap_load(l3) == 0) {
if (va != va_next) {
pmap_invalidate_range(pmap, va, sva);
va = va_next;
}
continue;
}
if (va == va_next)
va = sva;
if (pmap_remove_l3(pmap, l3, sva, l3_paddr, &free,
&lock)) {
sva += L3_SIZE;
break;
}
}
if (va != va_next)
pmap_invalidate_range(pmap, va, sva);
pmap_remove_l3_range(pmap, l3_paddr, sva, va_next, &free,
&lock);
}
if (lock != NULL)
rw_wunlock(lock);
@ -3419,8 +3475,7 @@ pmap_enter_l2(pmap_t pmap, vm_offset_t va, pd_entry_t new_l2, u_int flags,
vm_page_t m, struct rwlock **lockp)
{
struct spglist free;
pd_entry_t *l2, *l3, old_l2;
vm_offset_t sva;
pd_entry_t *l2, old_l2;
vm_page_t l2pg, mt;
PMAP_LOCK_ASSERT(pmap, MA_OWNED);
@ -3449,13 +3504,8 @@ pmap_enter_l2(pmap_t pmap, vm_offset_t va, pd_entry_t new_l2, u_int flags,
(void)pmap_remove_l2(pmap, l2, va,
pmap_load(pmap_l1(pmap, va)), &free, lockp);
else
for (sva = va; sva < va + L2_SIZE; sva += PAGE_SIZE) {
l3 = pmap_l2_to_l3(l2, sva);
if (pmap_l3_valid(pmap_load(l3)) &&
pmap_remove_l3(pmap, l3, sva, old_l2, &free,
lockp) != 0)
break;
}
pmap_remove_l3_range(pmap, old_l2, va, va + L2_SIZE,
&free, lockp);
vm_page_free_pages_toq(&free, true);
if (va >= VM_MAXUSER_ADDRESS) {
/*