Revision 2cc78eb52bc1ae89f0a4fa5a00eb998dffde4a9f authored by Linus Torvalds on 17 October 2005, 16:10:15 UTC, committed by Linus Torvalds on 17 October 2005, 16:10:15 UTC
Dipankar made RCU limit the batch size to improve latency, but that approach is unworkable: it can cause the RCU queues to grow without bounds, since the batch limiter ended up limiting the callbacks. So make the limit much higher, and start planning on instead limiting the batch size by doing RCU callbacks more often if the queue looks like it might be growing too long. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1 parent de21eb6
bfind.c
/*
* linux/fs/hfs/bfind.c
*
* Copyright (C) 2001
* Brad Boyer (flar@allandria.com)
* (C) 2003 Ardis Technologies <roman@ardistech.com>
*
* Search routines for btrees
*/
#include <linux/slab.h>
#include "btree.h"
int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
{
void *ptr;
fd->tree = tree;
fd->bnode = NULL;
ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
if (!ptr)
return -ENOMEM;
fd->search_key = ptr;
fd->key = ptr + tree->max_key_len + 2;
dprint(DBG_BNODE_REFS, "find_init: %d (%p)\n", tree->cnid, __builtin_return_address(0));
down(&tree->tree_lock);
return 0;
}
void hfs_find_exit(struct hfs_find_data *fd)
{
hfs_bnode_put(fd->bnode);
kfree(fd->search_key);
dprint(DBG_BNODE_REFS, "find_exit: %d (%p)\n", fd->tree->cnid, __builtin_return_address(0));
up(&fd->tree->tree_lock);
fd->tree = NULL;
}
/* Find the record in bnode that best matches key (not greater than...)*/
int __hfs_brec_find(struct hfs_bnode *bnode, struct hfs_find_data *fd)
{
int cmpval;
u16 off, len, keylen;
int rec;
int b, e;
int res;
b = 0;
e = bnode->num_recs - 1;
res = -ENOENT;
do {
rec = (e + b) / 2;
len = hfs_brec_lenoff(bnode, rec, &off);
keylen = hfs_brec_keylen(bnode, rec);
hfs_bnode_read(bnode, fd->key, off, keylen);
cmpval = bnode->tree->keycmp(fd->key, fd->search_key);
if (!cmpval) {
e = rec;
res = 0;
goto done;
}
if (cmpval < 0)
b = rec + 1;
else
e = rec - 1;
} while (b <= e);
//printk("%d: %d,%d,%d\n", bnode->this, b, e, rec);
if (rec != e && e >= 0) {
len = hfs_brec_lenoff(bnode, e, &off);
keylen = hfs_brec_keylen(bnode, e);
hfs_bnode_read(bnode, fd->key, off, keylen);
}
done:
fd->record = e;
fd->keyoffset = off;
fd->keylength = keylen;
fd->entryoffset = off + keylen;
fd->entrylength = len - keylen;
return res;
}
/* Traverse a B*Tree from the root to a leaf finding best fit to key */
/* Return allocated copy of node found, set recnum to best record */
int hfs_brec_find(struct hfs_find_data *fd)
{
struct hfs_btree *tree;
struct hfs_bnode *bnode;
u32 nidx, parent;
__be32 data;
int height, res;
tree = fd->tree;
if (fd->bnode)
hfs_bnode_put(fd->bnode);
fd->bnode = NULL;
nidx = tree->root;
if (!nidx)
return -ENOENT;
height = tree->depth;
res = 0;
parent = 0;
for (;;) {
bnode = hfs_bnode_find(tree, nidx);
if (IS_ERR(bnode)) {
res = PTR_ERR(bnode);
bnode = NULL;
break;
}
if (bnode->height != height)
goto invalid;
if (bnode->type != (--height ? HFS_NODE_INDEX : HFS_NODE_LEAF))
goto invalid;
bnode->parent = parent;
res = __hfs_brec_find(bnode, fd);
if (!height)
break;
if (fd->record < 0)
goto release;
parent = nidx;
hfs_bnode_read(bnode, &data, fd->entryoffset, 4);
nidx = be32_to_cpu(data);
hfs_bnode_put(bnode);
}
fd->bnode = bnode;
return res;
invalid:
printk("HFS: inconsistency in B*Tree (%d,%d,%d,%u,%u)\n",
height, bnode->height, bnode->type, nidx, parent);
res = -EIO;
release:
hfs_bnode_put(bnode);
return res;
}
int hfs_brec_read(struct hfs_find_data *fd, void *rec, int rec_len)
{
int res;
res = hfs_brec_find(fd);
if (res)
return res;
if (fd->entrylength > rec_len)
return -EINVAL;
hfs_bnode_read(fd->bnode, rec, fd->entryoffset, fd->entrylength);
return 0;
}
int hfs_brec_goto(struct hfs_find_data *fd, int cnt)
{
struct hfs_btree *tree;
struct hfs_bnode *bnode;
int idx, res = 0;
u16 off, len, keylen;
bnode = fd->bnode;
tree = bnode->tree;
if (cnt < 0) {
cnt = -cnt;
while (cnt > fd->record) {
cnt -= fd->record + 1;
fd->record = bnode->num_recs - 1;
idx = bnode->prev;
if (!idx) {
res = -ENOENT;
goto out;
}
hfs_bnode_put(bnode);
bnode = hfs_bnode_find(tree, idx);
if (IS_ERR(bnode)) {
res = PTR_ERR(bnode);
bnode = NULL;
goto out;
}
}
fd->record -= cnt;
} else {
while (cnt >= bnode->num_recs - fd->record) {
cnt -= bnode->num_recs - fd->record;
fd->record = 0;
idx = bnode->next;
if (!idx) {
res = -ENOENT;
goto out;
}
hfs_bnode_put(bnode);
bnode = hfs_bnode_find(tree, idx);
if (IS_ERR(bnode)) {
res = PTR_ERR(bnode);
bnode = NULL;
goto out;
}
}
fd->record += cnt;
}
len = hfs_brec_lenoff(bnode, fd->record, &off);
keylen = hfs_brec_keylen(bnode, fd->record);
fd->keyoffset = off;
fd->keylength = keylen;
fd->entryoffset = off + keylen;
fd->entrylength = len - keylen;
hfs_bnode_read(bnode, fd->key, off, keylen);
out:
fd->bnode = bnode;
return res;
}
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