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Commit 9a8ff578 authored by Mark Fasheh's avatar Mark Fasheh
Browse files

ocfs2: track local alloc state via debugfs 



A per-mount debugfs file, "local_alloc" is created which when read will
expose live state of the nodes local alloc file. Performance impact is
minimal, only a bit of memory overhead per mount point. Still, the code is
hidden behind CONFIG_OCFS2_FS_STATS. This feature will help us debug
local alloc performance problems on a live system.

Signed-off-by: default avatarMark Fasheh <mfasheh@suse.com>
parent 9c7af40b

fs/ocfs2/localalloc.c

+87 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/slab.h>

#include <linux/highmem.h>

#include <linux/bitops.h>

#include <linux/debugfs.h>



#define MLOG_MASK_PREFIX ML_DISK_ALLOC

#include <cluster/masklog.h>
@@ -73,6 +74,85 @@ static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb, 
static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,

					  struct inode *local_alloc_inode);



#ifdef CONFIG_OCFS2_FS_STATS



DEFINE_MUTEX(la_debug_mutex);



static int ocfs2_la_debug_open(struct inode *inode, struct file *file)

{

	file->private_data = inode->i_private;

	return 0;

}



#define LA_DEBUG_BUF_SZ	PAGE_CACHE_SIZE

#define LA_DEBUG_VER	1

static ssize_t ocfs2_la_debug_read(struct file *file, char __user *userbuf,

				   size_t count, loff_t *ppos)

{

	struct ocfs2_super *osb = file->private_data;

	int written, ret;

	char *buf = osb->local_alloc_debug_buf;



	mutex_lock(&la_debug_mutex);

	memset(buf, 0, LA_DEBUG_BUF_SZ);



	written = snprintf(buf, LA_DEBUG_BUF_SZ,

			   "0x%x\t0x%llx\t%u\t%u\t0x%x\n",

			   LA_DEBUG_VER,

			   (unsigned long long)osb->la_last_gd,

			   osb->local_alloc_default_bits,

			   osb->local_alloc_bits, osb->local_alloc_state);



	ret = simple_read_from_buffer(userbuf, count, ppos, buf, written);



	mutex_unlock(&la_debug_mutex);

	return ret;

}



static const struct file_operations ocfs2_la_debug_fops = {

	.open =		ocfs2_la_debug_open,

	.read =		ocfs2_la_debug_read,

};



static void ocfs2_init_la_debug(struct ocfs2_super *osb)

{

	osb->local_alloc_debug_buf = kmalloc(LA_DEBUG_BUF_SZ, GFP_NOFS);

	if (!osb->local_alloc_debug_buf)

		return;



	osb->local_alloc_debug = debugfs_create_file("local_alloc_stats",

						     S_IFREG|S_IRUSR,

						     osb->osb_debug_root,

						     osb,

						     &ocfs2_la_debug_fops);

	if (!osb->local_alloc_debug) {

		kfree(osb->local_alloc_debug_buf);

		osb->local_alloc_debug_buf = NULL;

	}

}



static void ocfs2_shutdown_la_debug(struct ocfs2_super *osb)

{

	if (osb->local_alloc_debug)

		debugfs_remove(osb->local_alloc_debug);



	if (osb->local_alloc_debug_buf)

		kfree(osb->local_alloc_debug_buf);



	osb->local_alloc_debug_buf = NULL;

	osb->local_alloc_debug = NULL;

}

#else	/* CONFIG_OCFS2_FS_STATS */

static void ocfs2_init_la_debug(struct ocfs2_super *osb)

{

	return;

}

static void ocfs2_shutdown_la_debug(struct ocfs2_super *osb)

{

	return;

}

#endif



static inline int ocfs2_la_state_enabled(struct ocfs2_super *osb)

{

	return (osb->local_alloc_state == OCFS2_LA_THROTTLED ||
@@ -146,6 +226,8 @@ int ocfs2_load_local_alloc(struct ocfs2_super *osb) 


	mlog_entry_void();



	ocfs2_init_la_debug(osb);



	if (osb->local_alloc_bits == 0)

		goto bail;
@@ -218,6 +300,9 @@ bail: 
	if (inode)

		iput(inode);



	if (status < 0)

		ocfs2_shutdown_la_debug(osb);



	mlog(0, "Local alloc window bits = %d\n", osb->local_alloc_bits);



	mlog_exit(status);
@@ -247,6 +332,8 @@ void ocfs2_shutdown_local_alloc(struct ocfs2_super *osb) 
	cancel_delayed_work(&osb->la_enable_wq);

	flush_workqueue(ocfs2_wq);



	ocfs2_shutdown_la_debug(osb);



	if (osb->local_alloc_state == OCFS2_LA_UNUSED)

		goto out;

fs/ocfs2/ocfs2.h

+5 −0
Original line number Diff line number Diff line
@@ -272,6 +272,11 @@ struct ocfs2_super 


	u64 la_last_gd;



#ifdef CONFIG_OCFS2_FS_STATS

	struct dentry *local_alloc_debug;

	char *local_alloc_debug_buf;

#endif



	/* Next two fields are for local node slot recovery during

	 * mount. */

	int dirty;