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Reduce the size of pv entries by 15%. This saves 1MB of KVA for mapping

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pv entries per 1GB of user virtual memory.  (eg: if we had 1GB file was
mmaped into 30 processes, that would theoretically reduce the KVA demand by
30MB for pv entries.  In reality though, we limit pv entries so we don't
have that many at once.)

We used to store the vm_page_t for the page table page.  But we recently
had the pa of the ptp, or can calculate it fairly quickly.  If we wanted
to avoid the shift/mask operation in pmap_pde(), we could recover the
pa but that means we have to store it for a while.

This does not measurably change performance.

Suggested by:  alc
Tested by:  alc
This commit is contained in:
peter 2004-06-29 15:57:05 +00:00
parent dd192c5d24
commit 486f03d1c3
2 changed files with 15 additions and 17 deletions
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31
sys/i386/i386/pmap.c
View File

@ -256,14 +256,13 @@ static int pmap_remove_pte(pmap_t pmap, pt_entry_t *ptq, vm_offset_t sva);
static void pmap_remove_page(struct pmap *pmap, vm_offset_t va);
static int pmap_remove_entry(struct pmap *pmap, vm_page_t m,
vm_offset_t va);
static void pmap_insert_entry(pmap_t pmap, vm_offset_t va,
vm_page_t mpte, vm_page_t m);
static void pmap_insert_entry(pmap_t pmap, vm_offset_t va, vm_page_t m);
static vm_page_t pmap_allocpte(pmap_t pmap, vm_offset_t va);
static vm_page_t _pmap_allocpte(pmap_t pmap, unsigned ptepindex);
static pt_entry_t *pmap_pte_quick(pmap_t pmap, vm_offset_t va);
static int pmap_unuse_pt(pmap_t, vm_offset_t, vm_page_t);
static int pmap_unuse_pt(pmap_t, vm_offset_t);
static vm_offset_t pmap_kmem_choose(vm_offset_t addr);
#ifdef PAE
static void *pmap_pdpt_allocf(uma_zone_t zone, int bytes, u_int8_t *flags, int wait);
@ -1057,12 +1056,15 @@ pmap_unwire_pte_hold(pmap_t pmap, vm_page_t m)
* conditionally free the page, and manage the hold/wire counts.
*/
static int
pmap_unuse_pt(pmap_t pmap, vm_offset_t va, vm_page_t mpte)
pmap_unuse_pt(pmap_t pmap, vm_offset_t va)
{
pd_entry_t ptepde;
vm_page_t mpte;
if (va >= VM_MAXUSER_ADDRESS)
return 0;
ptepde = *pmap_pde(pmap, va);
mpte = PHYS_TO_VM_PAGE(ptepde & PG_FRAME);
return pmap_unwire_pte_hold(pmap, mpte);
}
@ -1528,7 +1530,7 @@ pmap_remove_entry(pmap_t pmap, vm_page_t m, vm_offset_t va)
rtval = 0;
if (pv) {
rtval = pmap_unuse_pt(pmap, va, pv->pv_ptem);
rtval = pmap_unuse_pt(pmap, va);
TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
m->md.pv_list_count--;
if (TAILQ_FIRST(&m->md.pv_list) == NULL)
@ -1546,7 +1548,7 @@ pmap_remove_entry(pmap_t pmap, vm_page_t m, vm_offset_t va)
* (pmap, va).
*/
static void
pmap_insert_entry(pmap_t pmap, vm_offset_t va, vm_page_t mpte, vm_page_t m)
pmap_insert_entry(pmap_t pmap, vm_offset_t va, vm_page_t m)
{
pv_entry_t pv;
@ -1554,7 +1556,6 @@ pmap_insert_entry(pmap_t pmap, vm_offset_t va, vm_page_t mpte, vm_page_t m)
pv = get_pv_entry();
pv->pv_va = va;
pv->pv_pmap = pmap;
pv->pv_ptem = mpte;
vm_page_lock_queues();
TAILQ_INSERT_TAIL(&pmap->pm_pvlist, pv, pv_plist);
@ -1571,7 +1572,7 @@ static int
pmap_remove_pte(pmap_t pmap, pt_entry_t *ptq, vm_offset_t va)
{
pt_entry_t oldpte;
vm_page_t m, mpte;
vm_page_t m;
PMAP_LOCK_ASSERT(pmap, MA_OWNED);
oldpte = pte_load_clear(ptq);
@ -1601,8 +1602,7 @@ pmap_remove_pte(pmap_t pmap, pt_entry_t *ptq, vm_offset_t va)
vm_page_flag_set(m, PG_REFERENCED);
return pmap_remove_entry(pmap, m, va);
} else {
mpte = PHYS_TO_VM_PAGE(*pmap_pde(pmap, va));
return pmap_unuse_pt(pmap, va, mpte);
return pmap_unuse_pt(pmap, va);
}
}
@ -1770,7 +1770,7 @@ pmap_remove_all(vm_page_t m)
TAILQ_REMOVE(&pv->pv_pmap->pm_pvlist, pv, pv_plist);
TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
m->md.pv_list_count--;
pmap_unuse_pt(pv->pv_pmap, pv->pv_va, pv->pv_ptem);
pmap_unuse_pt(pv->pv_pmap, pv->pv_va);
PMAP_UNLOCK(pv->pv_pmap);
free_pv_entry(pv);
}
@ -2009,7 +2009,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
*/
if (pmap_initialized &&
(m->flags & (PG_FICTITIOUS|PG_UNMANAGED)) == 0) {
pmap_insert_entry(pmap, va, mpte, m);
pmap_insert_entry(pmap, va, m);
pa |= PG_MANAGED;
}
@ -2125,7 +2125,7 @@ pmap_enter_quick(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_page_t mpte)
* called at interrupt time.
*/
if ((m->flags & (PG_FICTITIOUS|PG_UNMANAGED)) == 0)
pmap_insert_entry(pmap, va, mpte, m);
pmap_insert_entry(pmap, va, m);
/*
* Increment counters
@ -2356,8 +2356,7 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_t dst_addr, vm_size_t len,
m = PHYS_TO_VM_PAGE(ptetemp);
*dst_pte = ptetemp & ~(PG_M | PG_A);
dst_pmap->pm_stats.resident_count++;
pmap_insert_entry(dst_pmap, addr,
dstmpte, m);
pmap_insert_entry(dst_pmap, addr, m);
} else {
vm_page_lock_queues();
pmap_unwire_pte_hold(dst_pmap, dstmpte);

1
sys/i386/include/pmap.h
View File

@ -317,7 +317,6 @@ typedef struct pv_entry {
vm_offset_t pv_va; /* virtual address for mapping */
TAILQ_ENTRY(pv_entry) pv_list;
TAILQ_ENTRY(pv_entry) pv_plist;
vm_page_t pv_ptem; /* VM page for pte */
} *pv_entry_t;
#ifdef _KERNEL