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Change vmapbuf() to use pmap_qenter() and vunmapbuf() to use pmap_qremove().

Browse Source 
This significantly reduces the number of TLB shootdowns caused by
vmapbuf/vunmapbuf when performing many large reads from raw disk devices.

Reviewed by:	dillon
This commit is contained in:
Tor Egge 2001-10-14 21:09:04 +00:00
parent 2334091845
commit 10ad529832
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=84935
2 changed files with 48 additions and 30 deletions
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39
sys/amd64/amd64/vm_machdep.c
View File

@ -344,15 +344,19 @@ vmapbuf(bp)
{
register caddr_t addr, v, kva;
vm_offset_t pa;
int pidx;
struct vm_page *m;
GIANT_REQUIRED;
if ((bp->b_flags & B_PHYS) == 0)
panic("vmapbuf");
for (v = bp->b_saveaddr, addr = (caddr_t)trunc_page((vm_offset_t)bp->b_data);
addr < bp->b_data + bp->b_bufsize;
addr += PAGE_SIZE, v += PAGE_SIZE) {
for (v = bp->b_saveaddr,
addr = (caddr_t)trunc_page((vm_offset_t)bp->b_data),
pidx = 0;
addr < bp->b_data + bp->b_bufsize;
addr += PAGE_SIZE, v += PAGE_SIZE, pidx++) {
/*
* Do the vm_fault if needed; do the copy-on-write thing
* when reading stuff off device into memory.
@ -362,11 +366,16 @@ vmapbuf(bp)
pa = trunc_page(pmap_kextract((vm_offset_t) addr));
if (pa == 0)
panic("vmapbuf: page not present");
vm_page_hold(PHYS_TO_VM_PAGE(pa));
pmap_kenter((vm_offset_t) v, pa);
m = PHYS_TO_VM_PAGE(pa);
vm_page_hold(m);
bp->b_pages[pidx] = m;
}
if (pidx > btoc(MAXPHYS))
panic("vmapbuf: mapped more than MAXPHYS");
pmap_qenter((vm_offset_t)bp->b_saveaddr, bp->b_pages, pidx);
kva = bp->b_saveaddr;
bp->b_npages = pidx;
bp->b_saveaddr = bp->b_data;
bp->b_data = kva + (((vm_offset_t) bp->b_data) & PAGE_MASK);
}
@ -379,21 +388,21 @@ void
vunmapbuf(bp)
register struct buf *bp;
{
register caddr_t addr;
vm_offset_t pa;
int pidx;
int npages;
vm_page_t *m;
GIANT_REQUIRED;
if ((bp->b_flags & B_PHYS) == 0)
panic("vunmapbuf");
for (addr = (caddr_t)trunc_page((vm_offset_t)bp->b_data);
addr < bp->b_data + bp->b_bufsize;
addr += PAGE_SIZE) {
pa = trunc_page(pmap_kextract((vm_offset_t) addr));
pmap_kremove((vm_offset_t) addr);
vm_page_unhold(PHYS_TO_VM_PAGE(pa));
}
npages = bp->b_npages;
pmap_qremove(trunc_page((vm_offset_t)bp->b_data),
npages);
m = bp->b_pages;
for (pidx = 0; pidx < npages; pidx++)
vm_page_unhold(*m++);
bp->b_data = bp->b_saveaddr;
}

39
sys/i386/i386/vm_machdep.c
View File

@ -344,15 +344,19 @@ vmapbuf(bp)
{
register caddr_t addr, v, kva;
vm_offset_t pa;
int pidx;
struct vm_page *m;
GIANT_REQUIRED;
if ((bp->b_flags & B_PHYS) == 0)
panic("vmapbuf");
for (v = bp->b_saveaddr, addr = (caddr_t)trunc_page((vm_offset_t)bp->b_data);
addr < bp->b_data + bp->b_bufsize;
addr += PAGE_SIZE, v += PAGE_SIZE) {
for (v = bp->b_saveaddr,
addr = (caddr_t)trunc_page((vm_offset_t)bp->b_data),
pidx = 0;
addr < bp->b_data + bp->b_bufsize;
addr += PAGE_SIZE, v += PAGE_SIZE, pidx++) {
/*
* Do the vm_fault if needed; do the copy-on-write thing
* when reading stuff off device into memory.
@ -362,11 +366,16 @@ vmapbuf(bp)
pa = trunc_page(pmap_kextract((vm_offset_t) addr));
if (pa == 0)
panic("vmapbuf: page not present");
vm_page_hold(PHYS_TO_VM_PAGE(pa));
pmap_kenter((vm_offset_t) v, pa);
m = PHYS_TO_VM_PAGE(pa);
vm_page_hold(m);
bp->b_pages[pidx] = m;
}
if (pidx > btoc(MAXPHYS))
panic("vmapbuf: mapped more than MAXPHYS");
pmap_qenter((vm_offset_t)bp->b_saveaddr, bp->b_pages, pidx);
kva = bp->b_saveaddr;
bp->b_npages = pidx;
bp->b_saveaddr = bp->b_data;
bp->b_data = kva + (((vm_offset_t) bp->b_data) & PAGE_MASK);
}
@ -379,21 +388,21 @@ void
vunmapbuf(bp)
register struct buf *bp;
{
register caddr_t addr;
vm_offset_t pa;
int pidx;
int npages;
vm_page_t *m;
GIANT_REQUIRED;
if ((bp->b_flags & B_PHYS) == 0)
panic("vunmapbuf");
for (addr = (caddr_t)trunc_page((vm_offset_t)bp->b_data);
addr < bp->b_data + bp->b_bufsize;
addr += PAGE_SIZE) {
pa = trunc_page(pmap_kextract((vm_offset_t) addr));
pmap_kremove((vm_offset_t) addr);
vm_page_unhold(PHYS_TO_VM_PAGE(pa));
}
npages = bp->b_npages;
pmap_qremove(trunc_page((vm_offset_t)bp->b_data),
npages);
m = bp->b_pages;
for (pidx = 0; pidx < npages; pidx++)
vm_page_unhold(*m++);
bp->b_data = bp->b_saveaddr;
}