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Code Issues Releases Activity

Add support for writing blocks to the loader's disk cache.

Browse Source 
PR:		kern/32389
Submitted by:	Jonathan Mini <mini@haikugeek.com>
Sponsored by:	ClickArray, Inc.
This commit is contained in:
John Baldwin 2001-12-11 00:10:00 +00:00
parent 3c3a6fe0e0
commit 4543c86ece
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=87634
1 changed files with 92 additions and 21 deletions
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113
sys/boot/common/bcache.c
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@ -63,6 +63,7 @@ static u_int bcache_hits, bcache_misses, bcache_ops, bcache_bypasses;
static u_int bcache_flushes;
static u_int bcache_bcount;
static void bcache_invalidate(daddr_t blkno);
static void bcache_insert(caddr_t buf, daddr_t blkno);
static int bcache_lookup(caddr_t buf, daddr_t blkno);
@ -116,16 +117,45 @@ bcache_flush(void)
}
}
/*
* Handle a transfer request; fill in parts of the request that can
/*
* Handle a write request; write directly to the disk, and populate the
* cache with the new values.
*/
static int
write_strategy(void *devdata, int unit, int rw, daddr_t blk, size_t size,
char *buf, size_t *rsize)
{
struct bcache_devdata *dd = (struct bcache_devdata *)devdata;
daddr_t i, nblk;
int err;
nblk = size / bcache_blksize;
/* Invalidate the blocks being written */
for (i = 0; i < nblk; i++) {
bcache_invalidate(blk + i);
}
/* Write the blocks */
err = dd->dv_strategy(dd->dv_devdata, rw, blk, size, buf, rsize);
/* Populate the block cache with the new data */
if (err == 0) {
for (i = 0; i < nblk; i++) {
bcache_insert(buf + (i * bcache_blksize),blk + i);
}
}
return err;
}
/*
* Handle a read request; fill in parts of the request that can
* be satisfied by the cache, use the supplied strategy routine to do
* device I/O and then use the I/O results to populate the cache.
*
* Requests larger than 1/2 the cache size will be bypassed and go
* directly to the disk. XXX tune this.
*/
int
bcache_strategy(void *devdata, int unit, int rw, daddr_t blk, size_t size,
static int
read_strategy(void *devdata, int unit, int rw, daddr_t blk, size_t size,
char *buf, size_t *rsize)
{
static int bcache_unit = -1;
@ -134,20 +164,6 @@ bcache_strategy(void *devdata, int unit, int rw, daddr_t blk, size_t size,
daddr_t p_blk, i, j, nblk;
caddr_t p_buf;
bcache_ops++;
if(bcache_unit != unit) {
bcache_flush();
bcache_unit = unit;
}
/* bypass large requests, or when the cache is inactive */
if ((bcache_data == NULL) || ((size * 2 / bcache_blksize) > bcache_nblks)) {
DEBUG("bypass %d from %d", size / bcache_blksize, blk);
bcache_bypasses++;
return(dd->dv_strategy(dd->dv_devdata, rw, blk, size, buf, rsize));
}
nblk = size / bcache_blksize;
result = 0;
@ -201,6 +217,43 @@ bcache_strategy(void *devdata, int unit, int rw, daddr_t blk, size_t size,
return(result);
}
/*
* Requests larger than 1/2 the cache size will be bypassed and go
* directly to the disk. XXX tune this.
*/
int
bcache_strategy(void *devdata, int unit, int rw, daddr_t blk, size_t size,
char *buf, size_t *rsize)
{
static int bcache_unit = -1;
struct bcache_devdata *dd = (struct bcache_devdata *)devdata;
int p_size, result;
daddr_t p_blk, i, j, nblk;
caddr_t p_buf;
bcache_ops++;
if(bcache_unit != unit) {
bcache_flush();
bcache_unit = unit;
}
/* bypass large requests, or when the cache is inactive */
if ((bcache_data == NULL) || ((size * 2 / bcache_blksize) > bcache_nblks)) {
DEBUG("bypass %d from %d", size / bcache_blksize, blk);
bcache_bypasses++;
return(dd->dv_strategy(dd->dv_devdata, rw, blk, size, buf, rsize));
}
switch (rw) {
case F_READ:
return read_strategy(devdata, unit, rw, blk, size, buf, rsize);
case F_WRITE:
return write_strategy(devdata, unit, rw, blk, size, buf, rsize);
}
return -1;
}
/*
* Insert a block into the cache. Retire the oldest block to do so, if required.
@ -261,6 +314,24 @@ bcache_lookup(caddr_t buf, daddr_t blkno)
return(ENOENT);
}
/*
* Invalidate a block from the cache.
*/
static void
bcache_invalidate(daddr_t blkno)
{
u_int i;
for (i = 0; i < bcache_nblks; i++) {
if (bcache_ctl[i].bc_blkno == blkno) {
bcache_ctl[i].bc_count = -1;
bcache_ctl[i].bc_blkno = -1;
DEBUG("invalidate blk %d", blkno);
break;
}
}
}
COMMAND_SET(bcachestat, "bcachestat", "get disk block cache stats", command_bcache);
static int