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Change the implementation of vm_hold_free_pages() so that it performs at

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most one call to pmap_qremove(), and thus one TLB shootdown, instead of one
call and TLB shootdown per page.

Simplify the interface to vm_hold_free_pages().

MFC after:	3 weeks
This commit is contained in:
Alan Cox 2010-07-11 20:11:44 +00:00
parent a2d81f6d1f
commit 2882388376
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=209902
1 changed files with 16 additions and 26 deletions
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42
sys/kern/vfs_bio.c
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@ -95,8 +95,7 @@ struct buf *buf; /* buffer header pool */
static struct proc *bufdaemonproc;
static int inmem(struct vnode *vp, daddr_t blkno);
static void vm_hold_free_pages(struct buf *bp, vm_offset_t from,
vm_offset_t to);
static void vm_hold_free_pages(struct buf *bp, int newbsize);
static void vm_hold_load_pages(struct buf *bp, vm_offset_t from,
vm_offset_t to);
static void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m);
@ -2888,10 +2887,7 @@ allocbuf(struct buf *bp, int size)
}
return 1;
}
vm_hold_free_pages(
bp,
(vm_offset_t) bp->b_data + newbsize,
(vm_offset_t) bp->b_data + bp->b_bufsize);
vm_hold_free_pages(bp, newbsize);
} else if (newbsize > bp->b_bufsize) {
/*
* We only use malloced memory on the first allocation.
@ -3766,31 +3762,25 @@ vm_hold_load_pages(struct buf *bp, vm_offset_t from, vm_offset_t to)
/* Return pages associated with this buf to the vm system */
static void
vm_hold_free_pages(struct buf *bp, vm_offset_t from, vm_offset_t to)
vm_hold_free_pages(struct buf *bp, int newbsize)
{
vm_offset_t pg;
vm_offset_t from;
vm_page_t p;
int index, newnpages;
from = round_page(from);
to = round_page(to);
newnpages = index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT;
for (pg = from; pg < to; pg += PAGE_SIZE, index++) {
from = round_page((vm_offset_t)bp->b_data + newbsize);
newnpages = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT;
if (bp->b_npages > newnpages)
pmap_qremove(from, bp->b_npages - newnpages);
for (index = newnpages; index < bp->b_npages; index++) {
p = bp->b_pages[index];
if (p && (index < bp->b_npages)) {
if (p->busy) {
printf(
"vm_hold_free_pages: blkno: %jd, lblkno: %jd\n",
(intmax_t)bp->b_blkno,
(intmax_t)bp->b_lblkno);
}
bp->b_pages[index] = NULL;
pmap_qremove(pg, 1);
p->wire_count--;
vm_page_free(p);
atomic_subtract_int(&cnt.v_wire_count, 1);
}
bp->b_pages[index] = NULL;
if (p->busy != 0)
printf("vm_hold_free_pages: blkno: %jd, lblkno: %jd\n",
(intmax_t)bp->b_blkno, (intmax_t)bp->b_lblkno);
p->wire_count--;
vm_page_free(p);
atomic_subtract_int(&cnt.v_wire_count, 1);
}
bp->b_npages = newnpages;
}