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Fix 4 problems:

Browse Source 
Major: When blocking occurs in allocbuf() for VMIO files,
	       excess wire counts could accumulate.
	Major: Pages are incorrectly accumulated into the physical
	       buffer for clustered reads.  This happens when bogus
	       page is needed.
	Minor: When reclaiming buffers, the async flag on the buffer
	       needs to be zero, or the reclaim is not optimal.
	Minor: The age flag should be cleared, if a buffer is wanted.
This commit is contained in:
John Dyson 1996-10-06 07:50:05 +00:00
parent 1f3a0ea7fd
commit ffe2522e29
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=18737
2 changed files with 29 additions and 14 deletions
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29
sys/kern/vfs_bio.c
View File

@ -18,7 +18,7 @@
* 5. Modifications may be freely made to this file if the above conditions
* are met.
*
* $Id: vfs_bio.c,v 1.101 1996/09/18 15:57:41 dyson Exp $
* $Id: vfs_bio.c,v 1.102 1996/09/20 02:26:35 dyson Exp $
*/
/*
@ -112,10 +112,7 @@ static struct bqueues bufqueues[BUFFER_QUEUES];
extern int vm_swap_size;
#define BUF_MAXUSE 8
/*
#define NO_B_MALLOC
*/
#define BUF_MAXUSE 16
/*
* Initialize buffer headers and related structures.
@ -464,7 +461,7 @@ brelse(struct buf * bp)
/* anyone need this block? */
if (bp->b_flags & B_WANTED) {
bp->b_flags &= ~B_WANTED;
bp->b_flags &= ~(B_WANTED | B_AGE);
wakeup(bp);
}
@ -664,9 +661,9 @@ vfs_vmio_release(bp)
tsleep(m, PVM, "vmiorl", 0);
}
}
vm_page_unwire(m);
if (m->wire_count == 0) {
if (m->flags & PG_WANTED) {
@ -860,6 +857,12 @@ getnewbuf(int slpflag, int slptimeo, int doingvmio)
return (0);
}
#if defined(DIAGNOSTIC)
if (bp->b_flags & B_BUSY) {
panic("getnewbuf: busy buffer on free list\n");
}
#endif
/*
* We are fairly aggressive about freeing VMIO buffers, but since
* the buffering is intact without buffer headers, there is not
@ -894,8 +897,10 @@ getnewbuf(int slpflag, int slptimeo, int doingvmio)
bremfree(bp);
bp->b_flags |= B_BUSY;
if (bp->b_flags & B_VMIO)
if (bp->b_flags & B_VMIO) {
bp->b_flags &= ~B_ASYNC;
vfs_vmio_release(bp);
}
if (bp->b_vp)
brelvp(bp);
@ -1303,6 +1308,10 @@ allocbuf(struct buf * bp, int size)
* is the responsibility of vnode_pager_setsize
*/
m = bp->b_pages[i];
#if defined(DIAGNOSTIC)
if (m == bogus_page)
panic("allocbuf: bogus page found");
#endif
s = splvm();
while ((m->flags & PG_BUSY) || (m->busy != 0)) {
m->flags |= PG_WANTED;
@ -1339,8 +1348,8 @@ allocbuf(struct buf * bp, int size)
if (tinc > bsize)
tinc = bsize;
off = (vm_ooffset_t) bp->b_lblkno * bsize;
doretry:
curbpnpages = bp->b_npages;
doretry:
bp->b_flags |= B_CACHE;
for (toff = 0; toff < newbsize; toff += tinc) {
int bytesinpage;

14
sys/kern/vfs_cluster.c
View File

@ -33,7 +33,7 @@
* SUCH DAMAGE.
*
* @(#)vfs_cluster.c 8.7 (Berkeley) 2/13/94
* $Id: vfs_cluster.c,v 1.36 1996/06/03 04:40:35 dyson Exp $
* $Id: vfs_cluster.c,v 1.37 1996/07/27 18:49:18 dyson Exp $
*/
#include <sys/param.h>
@ -368,18 +368,24 @@ cluster_rbuild(vp, filesize, lbn, blkno, size, run)
m = tbp->b_pages[j];
++m->busy;
++m->object->paging_in_progress;
if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) {
m = bogus_page;
}
if ((bp->b_npages == 0) ||
(bp->b_pages[bp->b_npages-1] != m)) {
bp->b_pages[bp->b_npages] = m;
bp->b_npages++;
}
if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL)
tbp->b_pages[j] = bogus_page;
}
bp->b_bcount += tbp->b_bcount;
bp->b_bufsize += tbp->b_bufsize;
}
for(j=0;j<bp->b_npages;j++) {
if ((bp->b_pages[j]->valid & VM_PAGE_BITS_ALL) ==
VM_PAGE_BITS_ALL)
bp->b_pages[j] = bogus_page;
}
pmap_qenter(trunc_page((vm_offset_t) bp->b_data),
(vm_page_t *)bp->b_pages, bp->b_npages);
return (bp);