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Implement pmap_advise(). (Without a working pmap_advise() implementation

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madvise(MADV_DONTNEED) and madvise(MADV_FREE) are NOPs.)

Reviewed by:	markj
X-MFC after:	r350004
Differential Revision:	https://reviews.freebsd.org/D21062
This commit is contained in:
Alan Cox 2019-07-26 05:07:09 +00:00
parent ae8828bad1
commit b3d6ea5bc2
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=350347
1 changed files with 105 additions and 1 deletions
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106
sys/arm64/arm64/pmap.c
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@ -2499,7 +2499,7 @@ pmap_remove_l2(pmap_t pmap, pt_entry_t *l2, vm_offset_t sva,
/*
* pmap_remove_l3: do the things to unmap a page in a process
*/
static int __unused
static int
pmap_remove_l3(pmap_t pmap, pt_entry_t *l3, vm_offset_t va,
pd_entry_t l2e, struct spglist *free, struct rwlock **lockp)
{
@ -4839,6 +4839,110 @@ pmap_ts_referenced(vm_page_t m)
void
pmap_advise(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, int advice)
{
struct rwlock *lock;
vm_offset_t va, va_next;
vm_page_t m;
pd_entry_t *l0, *l1, *l2, oldl2;
pt_entry_t *l3, oldl3;
if (advice != MADV_DONTNEED && advice != MADV_FREE)
return;
PMAP_LOCK(pmap);
for (; sva < eva; sva = va_next) {
l0 = pmap_l0(pmap, sva);
if (pmap_load(l0) == 0) {
va_next = (sva + L0_SIZE) & ~L0_OFFSET;
if (va_next < sva)
va_next = eva;
continue;
}
l1 = pmap_l0_to_l1(l0, sva);
if (pmap_load(l1) == 0) {
va_next = (sva + L1_SIZE) & ~L1_OFFSET;
if (va_next < sva)
va_next = eva;
continue;
}
va_next = (sva + L2_SIZE) & ~L2_OFFSET;
if (va_next < sva)
va_next = eva;
l2 = pmap_l1_to_l2(l1, sva);
oldl2 = pmap_load(l2);
if (oldl2 == 0)
continue;
if ((oldl2 & ATTR_DESCR_MASK) == L2_BLOCK) {
if ((oldl2 & ATTR_SW_MANAGED) == 0)
continue;
lock = NULL;
if (!pmap_demote_l2_locked(pmap, l2, sva, &lock)) {
if (lock != NULL)
rw_wunlock(lock);
/*
* The 2MB page mapping was destroyed.
*/
continue;
}
/*
* Unless the page mappings are wired, remove the
* mapping to a single page so that a subsequent
* access may repromote. Since the underlying page
* table page is fully populated, this removal never
* frees a page table page.
*/
if ((oldl2 & ATTR_SW_WIRED) == 0) {
l3 = pmap_l2_to_l3(l2, sva);
KASSERT(pmap_load(l3) != 0,
("pmap_advise: invalid PTE"));
pmap_remove_l3(pmap, l3, sva, pmap_load(l2),
NULL, &lock);
}
if (lock != NULL)
rw_wunlock(lock);
}
KASSERT((pmap_load(l2) & ATTR_DESCR_MASK) == L2_TABLE,
("pmap_advise: invalid L2 entry after demotion"));
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) {
oldl3 = pmap_load(l3);
if ((oldl3 & (ATTR_SW_MANAGED | ATTR_DESCR_MASK)) !=
(ATTR_SW_MANAGED | L3_PAGE))
goto maybe_invlrng;
else if (pmap_pte_dirty(oldl3)) {
if (advice == MADV_DONTNEED) {
/*
* Future calls to pmap_is_modified()
* can be avoided by making the page
* dirty now.
*/
m = PHYS_TO_VM_PAGE(oldl3 & ~ATTR_MASK);
vm_page_dirty(m);
}
while (!atomic_fcmpset_long(l3, &oldl3,
(oldl3 & ~ATTR_AF) | ATTR_AP(ATTR_AP_RO)))
cpu_spinwait();
} else if ((oldl3 & ATTR_AF) != 0)
pmap_clear_bits(l3, ATTR_AF);
else
goto maybe_invlrng;
if (va == va_next)
va = sva;
continue;
maybe_invlrng:
if (va != va_next) {
pmap_invalidate_range(pmap, va, sva);
va = va_next;
}
}
if (va != va_next)
pmap_invalidate_range(pmap, va, sva);
}
PMAP_UNLOCK(pmap);
}
/*