xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

jbd2: convert instrumentation from markers to tracepoints

Browse Source 
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o
2009-06-17 11:47:48 -04:00
parent 65795efbd3
commit 879c5e6b7c
5 changed files with 252 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

69
fs/jbd2/journal.c
View File

@@ -38,6 +38,10 @@
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/math64.h>
#include <linux/hash.h>
#define CREATE_TRACE_POINTS
#include <trace/events/jbd2.h>
#include <asm/uaccess.h>
#include <asm/page.h>
@@ -2377,6 +2381,71 @@ static void __exit journal_exit(void)
jbd2_journal_destroy_caches();
}
/*
* jbd2_dev_to_name is a utility function used by the jbd2 and ext4
* tracing infrastructure to map a dev_t to a device name.
*
* The caller should use rcu_read_lock() in order to make sure the
* device name stays valid until its done with it. We use
* rcu_read_lock() as well to make sure we're safe in case the caller
* gets sloppy, and because rcu_read_lock() is cheap and can be safely
* nested.
*/
struct devname_cache {
struct rcu_head rcu;
dev_t device;
char devname[BDEVNAME_SIZE];
};
#define CACHE_SIZE_BITS 6
static struct devname_cache *devcache[1 << CACHE_SIZE_BITS];
static DEFINE_SPINLOCK(devname_cache_lock);
static void free_devcache(struct rcu_head *rcu)
{
kfree(rcu);
}
const char *jbd2_dev_to_name(dev_t device)
{
int i = hash_32(device, CACHE_SIZE_BITS);
char *ret;
struct block_device *bd;
rcu_read_lock();
if (devcache[i] && devcache[i]->device == device) {
ret = devcache[i]->devname;
rcu_read_unlock();
return ret;
}
rcu_read_unlock();
spin_lock(&devname_cache_lock);
if (devcache[i]) {
if (devcache[i]->device == device) {
ret = devcache[i]->devname;
spin_unlock(&devname_cache_lock);
return ret;
}
call_rcu(&devcache[i]->rcu, free_devcache);
}
devcache[i] = kmalloc(sizeof(struct devname_cache), GFP_KERNEL);
if (!devcache[i]) {
spin_unlock(&devname_cache_lock);
return "NODEV-ALLOCFAILURE"; /* Something non-NULL */
}
devcache[i]->device = device;
bd = bdget(device);
if (bd) {
bdevname(bd, devcache[i]->devname);
bdput(bd);
} else
__bdevname(device, devcache[i]->devname);
ret = devcache[i]->devname;
spin_unlock(&devname_cache_lock);
return ret;
}
EXPORT_SYMBOL(jbd2_dev_to_name);
MODULE_LICENSE("GPL");
module_init(journal_init);
module_exit(journal_exit);