Commit 2baba250 authored by Yehuda Sadeh's avatar Yehuda Sadeh Committed by Sage Weil
Browse files

ceph: writeback congestion control 



Set bdi congestion bit when amount of write data in flight exceeds adjustable
threshold.

Signed-off-by: default avatarYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent dbd646a8

fs/ceph/addr.c

+33 −2
Original line number Diff line number Diff line
@@ -47,6 +47,12 @@ 
 * accounting is preserved.

 */



#define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))

#define CONGESTION_OFF_THRESH(congestion_kb)				\

	(CONGESTION_ON_THRESH(congestion_kb) -				\

	 (CONGESTION_ON_THRESH(congestion_kb) >> 2))







/*

 * Dirty a page.  Optimistically adjust accounting, on the assumption
@@ -377,6 +383,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc) 
{

	struct inode *inode;

	struct ceph_inode_info *ci;

	struct ceph_client *client;

	struct ceph_osd_client *osdc;

	loff_t page_off = page->index << PAGE_CACHE_SHIFT;

	int len = PAGE_CACHE_SIZE;
@@ -384,6 +391,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc) 
	int err = 0;

	struct ceph_snap_context *snapc;

	u64 snap_size = 0;

	long writeback_stat;



	dout("writepage %p idx %lu\n", page, page->index);
@@ -393,7 +401,8 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc) 
	}

	inode = page->mapping->host;

	ci = ceph_inode(inode);

	osdc = &ceph_inode_to_client(inode)->osdc;

	client = ceph_inode_to_client(inode);

	osdc = &client->osdc;



	/* verify this is a writeable snap context */

	snapc = (void *)page->private;
@@ -420,6 +429,11 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc) 
	dout("writepage %p page %p index %lu on %llu~%u\n",

	     inode, page, page->index, page_off, len);



	writeback_stat = atomic_long_inc_return(&client->writeback_count);

	if (writeback_stat >

	    CONGESTION_ON_THRESH(client->mount_args->congestion_kb))

		set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);



	set_page_writeback(page);

	err = ceph_osdc_writepages(osdc, ceph_vino(inode),

				   &ci->i_layout, snapc,
@@ -499,6 +513,8 @@ static void writepages_finish(struct ceph_osd_request *req, 
	struct writeback_control *wbc = req->r_wbc;

	__s32 rc = -EIO;

	u64 bytes = 0;

	struct ceph_client *client = ceph_inode_to_client(inode);

	long writeback_stat;



	/* parse reply */

	replyhead = msg->front.iov_base;
@@ -524,6 +540,13 @@ static void writepages_finish(struct ceph_osd_request *req, 
		BUG_ON(!page);

		WARN_ON(!PageUptodate(page));



		writeback_stat =

			atomic_long_dec_return(&client->writeback_count);

		if (writeback_stat <

		    CONGESTION_OFF_THRESH(client->mount_args->congestion_kb))

			clear_bdi_congested(&client->backing_dev_info,

					    BLK_RW_ASYNC);



		if (i >= wrote) {

			dout("inode %p skipping page %p\n", inode, page);

			wbc->pages_skipped++;
@@ -666,6 +689,7 @@ static int ceph_writepages_start(struct address_space *mapping, 
		u64 offset, len;

		struct ceph_osd_request_head *reqhead;

		struct ceph_osd_op *op;

		long writeback_stat;



		next = 0;

		locked_pages = 0;
@@ -773,6 +797,12 @@ static int ceph_writepages_start(struct address_space *mapping, 
				first = i;

			dout("%p will write page %p idx %lu\n",

			     inode, page, page->index);



			writeback_stat = atomic_long_inc_return(&client->writeback_count);

			if (writeback_stat > CONGESTION_ON_THRESH(client->mount_args->congestion_kb)) {

				set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);

			}



			set_page_writeback(page);

			req->r_pages[locked_pages] = page;

			locked_pages++;
@@ -998,7 +1028,8 @@ static int ceph_write_end(struct file *file, struct address_space *mapping, 
			  struct page *page, void *fsdata)

{

	struct inode *inode = file->f_dentry->d_inode;

	struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;

	struct ceph_client *client = ceph_inode_to_client(inode);

	struct ceph_mds_client *mdsc = &client->mdsc;

	unsigned from = pos & (PAGE_CACHE_SIZE - 1);

	int check_cap = 0;

fs/ceph/debugfs.c

+33 −0
Original line number Diff line number Diff line
@@ -320,6 +320,30 @@ DEFINE_SHOW_FUNC(osdc_show) 
DEFINE_SHOW_FUNC(dentry_lru_show)

DEFINE_SHOW_FUNC(caps_show)



static int congestion_kb_set(void *data, u64 val)

{

	struct ceph_client *client = (struct ceph_client *)data;



	if (client)

		client->mount_args->congestion_kb = (int)val;



	return 0;

}



static int congestion_kb_get(void *data, u64 *val)

{

	struct ceph_client *client = (struct ceph_client *)data;



	if (client)

		*val = (u64)client->mount_args->congestion_kb;



	return 0;

}





DEFINE_SIMPLE_ATTRIBUTE(congestion_kb_fops, congestion_kb_get,

			congestion_kb_set, "%llu\n");



int __init ceph_debugfs_init(void)

{

	ceph_debugfs_dir = debugfs_create_dir("ceph", NULL);
@@ -409,6 +433,14 @@ int ceph_debugfs_client_init(struct ceph_client *client) 
	if (!client->debugfs_caps)

		goto out;



	client->debugfs_congestion_kb = debugfs_create_file("writeback_congestion_kb",

						   0600,

						   client->debugfs_dir,

						   client,

						   &congestion_kb_fops);

	if (!client->debugfs_congestion_kb)

		goto out;



	sprintf(name, "../../bdi/%s", dev_name(client->sb->s_bdi->dev));

	client->debugfs_bdi = debugfs_create_symlink("bdi", client->debugfs_dir,

						     name);
@@ -431,6 +463,7 @@ void ceph_debugfs_client_cleanup(struct ceph_client *client) 
	debugfs_remove(client->osdc.debugfs_file);

	debugfs_remove(client->mdsc.debugfs_file);

	debugfs_remove(client->monc.debugfs_file);

	debugfs_remove(client->debugfs_congestion_kb);

	debugfs_remove(client->debugfs_dir);

}

fs/ceph/super.c

+36 −0
Original line number Diff line number Diff line
@@ -150,6 +150,35 @@ static void ceph_inode_init_once(void *foo) 
	inode_init_once(&ci->vfs_inode);

}



static int default_congestion_kb(void)

{

	int congestion_kb;



	/*

	 * Copied from NFS

	 *

	 * congestion size, scale with available memory.

	 *

	 *  64MB:    8192k

	 * 128MB:   11585k

	 * 256MB:   16384k

	 * 512MB:   23170k

	 *   1GB:   32768k

	 *   2GB:   46340k

	 *   4GB:   65536k

	 *   8GB:   92681k

	 *  16GB:  131072k

	 *

	 * This allows larger machines to have larger/more transfers.

	 * Limit the default to 256M

	 */

	congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);

	if (congestion_kb > 256*1024)

		congestion_kb = 256*1024;



	return congestion_kb;

}



static int __init init_caches(void)

{

	ceph_inode_cachep = kmem_cache_create("ceph_inode_info",
@@ -267,6 +296,7 @@ enum { 
	Opt_caps_wanted_delay_min,

	Opt_caps_wanted_delay_max,

	Opt_readdir_max_entries,

	Opt_congestion_kb,

	Opt_last_int,

	/* int args above */

	Opt_snapdirname,
@@ -295,6 +325,7 @@ static match_table_t arg_tokens = { 
	{Opt_caps_wanted_delay_min, "caps_wanted_delay_min=%d"},

	{Opt_caps_wanted_delay_max, "caps_wanted_delay_max=%d"},

	{Opt_readdir_max_entries, "readdir_max_entries=%d"},

	{Opt_congestion_kb, "write_congestion_kb=%d"},

	/* int args above */

	{Opt_snapdirname, "snapdirname=%s"},

	{Opt_name, "name=%s"},
@@ -342,6 +373,7 @@ static struct ceph_mount_args *parse_mount_args(int flags, char *options, 
	args->snapdir_name = kstrdup(CEPH_SNAPDIRNAME_DEFAULT, GFP_KERNEL);

	args->cap_release_safety = CEPH_CAPS_PER_RELEASE * 4;

	args->max_readdir = 1024;

	args->congestion_kb = default_congestion_kb();



	/* ip1[:port1][,ip2[:port2]...]:/subdir/in/fs */

	err = -EINVAL;
@@ -445,6 +477,9 @@ static struct ceph_mount_args *parse_mount_args(int flags, char *options, 
		case Opt_readdir_max_entries:

			args->max_readdir = intval;

			break;

		case Opt_congestion_kb:

			args->congestion_kb = intval;

			break;



		case Opt_noshare:

			args->flags |= CEPH_OPT_NOSHARE;
@@ -516,6 +551,7 @@ static struct ceph_client *ceph_create_client(struct ceph_mount_args *args) 
	client->msgr = NULL;



	client->mount_err = 0;

	atomic_long_set(&client->writeback_count, 0);



	err = bdi_init(&client->backing_dev_info);

	if (err < 0)

fs/ceph/super.h

+3 −0
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ struct ceph_mount_args { 
	int wsize;

	int rsize;            /* max readahead */

	int max_readdir;      /* max readdir size */

	int congestion_kb;      /* max readdir size */

	int osd_timeout;

	char *snapdir_name;   /* default ".snap" */

	char *name;
@@ -136,6 +137,7 @@ struct ceph_client { 
	struct workqueue_struct *wb_wq;

	struct workqueue_struct *pg_inv_wq;

	struct workqueue_struct *trunc_wq;

	atomic_long_t writeback_count;



	struct backing_dev_info backing_dev_info;
@@ -143,6 +145,7 @@ struct ceph_client { 
	struct dentry *debugfs_monmap;

	struct dentry *debugfs_mdsmap, *debugfs_osdmap;

	struct dentry *debugfs_dir, *debugfs_dentry_lru, *debugfs_caps;

	struct dentry *debugfs_congestion_kb;

	struct dentry *debugfs_bdi;

#endif

};