[GFS2] Reduce number of gfs2_scand processes to one
We only need a single gfs2_scand process rather than the one
per filesystem which we had previously. As a result the parameter
determining the frequency of gfs2_scand runs becomes a module
parameter rather than a mount parameter as it was before.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 0054b7d..559937c7 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -25,6 +25,8 @@
#include <asm/uaccess.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
#include "gfs2.h"
#include "incore.h"
@@ -58,6 +60,8 @@
static void gfs2_glock_drop_th(struct gfs2_glock *gl);
static DECLARE_RWSEM(gfs2_umount_flush_sem);
static struct dentry *gfs2_root;
+static struct task_struct *scand_process;
+static unsigned int scand_secs = 5;
#define GFS2_GL_HASH_SHIFT 15
#define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
@@ -1627,7 +1631,7 @@
goto out;
gl = list_entry(head->first, struct gfs2_glock, gl_list);
while(1) {
- if (gl->gl_sbd == sdp) {
+ if (!sdp || gl->gl_sbd == sdp) {
gfs2_glock_hold(gl);
read_unlock(gl_lock_addr(hash));
if (prev)
@@ -1645,6 +1649,7 @@
read_unlock(gl_lock_addr(hash));
if (prev)
gfs2_glock_put(prev);
+ cond_resched();
return has_entries;
}
@@ -1673,20 +1678,6 @@
}
/**
- * gfs2_scand_internal - Look for glocks and inodes to toss from memory
- * @sdp: the filesystem
- *
- */
-
-void gfs2_scand_internal(struct gfs2_sbd *sdp)
-{
- unsigned int x;
-
- for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
- examine_bucket(scan_glock, sdp, x);
-}
-
-/**
* clear_glock - look at a glock and see if we can free it from glock cache
* @gl: the glock to look at
*
@@ -1973,6 +1964,35 @@
return error;
}
+/**
+ * gfs2_scand - Look for cached glocks and inodes to toss from memory
+ * @sdp: Pointer to GFS2 superblock
+ *
+ * One of these daemons runs, finding candidates to add to sd_reclaim_list.
+ * See gfs2_glockd()
+ */
+
+static int gfs2_scand(void *data)
+{
+ unsigned x;
+ unsigned delay;
+
+ while (!kthread_should_stop()) {
+ for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
+ examine_bucket(scan_glock, NULL, x);
+ if (freezing(current))
+ refrigerator();
+ delay = scand_secs;
+ if (delay < 1)
+ delay = 1;
+ schedule_timeout_interruptible(delay * HZ);
+ }
+
+ return 0;
+}
+
+
+
int __init gfs2_glock_init(void)
{
unsigned i;
@@ -1984,9 +2004,22 @@
rwlock_init(&gl_hash_locks[i]);
}
#endif
+
+ scand_process = kthread_run(gfs2_scand, NULL, "gfs2_scand");
+ if (IS_ERR(scand_process))
+ return PTR_ERR(scand_process);
+
return 0;
}
+void gfs2_glock_exit(void)
+{
+ kthread_stop(scand_process);
+}
+
+module_param(scand_secs, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(scand_secs, "The number of seconds between scand runs");
+
static int gfs2_glock_iter_next(struct glock_iter *gi)
{
struct gfs2_glock *gl;