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Avoid pointless zeroing of the bogus page in vfs_bio_clrbuf().

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Suggested by:	tegge@	(from October of last year)
This commit is contained in:
Alan Cox 2004-05-08 06:46:40 +00:00
parent c7a0a4c076
commit ec1100fc6e
1 changed files with 8 additions and 6 deletions
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14
sys/kern/vfs_bio.c
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@ -3522,7 +3522,7 @@ vfs_bio_set_validclean(struct buf *bp, int base, int size)
void
vfs_bio_clrbuf(struct buf *bp)
{
int i, mask = 0;
int i, j, mask = 0;
caddr_t sa, ea;
GIANT_REQUIRED;
@ -3533,9 +3533,10 @@ vfs_bio_clrbuf(struct buf *bp)
VM_OBJECT_LOCK(bp->b_object);
if( (bp->b_npages == 1) && (bp->b_bufsize < PAGE_SIZE) &&
(bp->b_offset & PAGE_MASK) == 0) {
if (bp->b_pages[0] == bogus_page)
goto unlock;
mask = (1 << (bp->b_bufsize / DEV_BSIZE)) - 1;
if (bp->b_pages[0] != bogus_page)
VM_OBJECT_LOCK_ASSERT(bp->b_pages[0]->object, MA_OWNED);
VM_OBJECT_LOCK_ASSERT(bp->b_pages[0]->object, MA_OWNED);
if ((bp->b_pages[0]->valid & mask) == mask)
goto unlock;
if (((bp->b_pages[0]->flags & PG_ZERO) == 0) &&
@ -3547,14 +3548,15 @@ vfs_bio_clrbuf(struct buf *bp)
}
ea = sa = bp->b_data;
for(i=0;i<bp->b_npages;i++,sa=ea) {
int j = ((vm_offset_t)sa & PAGE_MASK) / DEV_BSIZE;
if (bp->b_pages[i] == bogus_page)
continue;
j = ((vm_offset_t)sa & PAGE_MASK) / DEV_BSIZE;
ea = (caddr_t)trunc_page((vm_offset_t)sa + PAGE_SIZE);
ea = (caddr_t)(vm_offset_t)ulmin(
(u_long)(vm_offset_t)ea,
(u_long)(vm_offset_t)bp->b_data + bp->b_bufsize);
mask = ((1 << ((ea - sa) / DEV_BSIZE)) - 1) << j;
if (bp->b_pages[i] != bogus_page)
VM_OBJECT_LOCK_ASSERT(bp->b_pages[i]->object, MA_OWNED);
VM_OBJECT_LOCK_ASSERT(bp->b_pages[i]->object, MA_OWNED);
if ((bp->b_pages[i]->valid & mask) == mask)
continue;
if ((bp->b_pages[i]->valid & mask) == 0) {