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Commit 6c0c42cd authored by Artem Bityutskiy's avatar Artem Bityutskiy
Browse files

UBIFS: do not allocate too much 



Bulk-read allocates 128KiB or more using kmalloc. The allocation
starts failing often when the memory gets fragmented. UBIFS still
works fine in this case, because it falls-back to standard
(non-optimized) read method, though. This patch teaches bulk-read
to allocate exactly the amount of memory it needs, instead of
allocating 128KiB every time.

This patch is also a preparation to the further fix where we'll
have a pre-allocated bulk-read buffer as well. For example, now
the @bu object is prepared in 'ubifs_bulk_read()', so we could
path either pre-allocated or allocated information to
'ubifs_do_bulk_read()' later. Or teaching 'ubifs_do_bulk_read()'
not to allocate 'bu->buf' if it is already there.

Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent 39ce81ce

fs/ubifs/file.c

+46 −24
Original line number Original line Diff line number Diff line
@@ -691,32 +691,22 @@ static int populate_page(struct ubifs_info *c, struct page *page, 
/**

/**

 * ubifs_do_bulk_read - do bulk-read.

 * ubifs_do_bulk_read - do bulk-read.

 * @c: UBIFS file-system description object

 * @c: UBIFS file-system description object

 * @page1: first page

 * @bu: bulk-read information

 * @page1: first page to read

 *

 *

 * This function returns %1 if the bulk-read is done, otherwise %0 is returned.

 * This function returns %1 if the bulk-read is done, otherwise %0 is returned.

 */

 */

static int ubifs_do_bulk_read(struct ubifs_info *c, struct page *page1)

static int ubifs_do_bulk_read(struct ubifs_info *c, struct bu_info *bu,

			      struct page *page1)

{

{

	pgoff_t offset = page1->index, end_index;

	pgoff_t offset = page1->index, end_index;

	struct address_space *mapping = page1->mapping;

	struct address_space *mapping = page1->mapping;

	struct inode *inode = mapping->host;

	struct inode *inode = mapping->host;

	struct ubifs_inode *ui = ubifs_inode(inode);

	struct ubifs_inode *ui = ubifs_inode(inode);

	struct bu_info *bu;

	int err, page_idx, page_cnt, ret = 0, n = 0;

	int err, page_idx, page_cnt, ret = 0, n = 0;

	int allocate = bu->buf ? 0 : 1;

	loff_t isize;

	loff_t isize;





	bu = kmalloc(sizeof(struct bu_info), GFP_NOFS | __GFP_NOWARN);

	if (!bu)

		return 0;



	bu->buf_len = c->bulk_read_buf_size;

	bu->buf = kmalloc(bu->buf_len, GFP_NOFS | __GFP_NOWARN);

	if (!bu->buf)

		goto out_free;



	data_key_init(c, &bu->key, inode->i_ino,

		      offset << UBIFS_BLOCKS_PER_PAGE_SHIFT);



	err = ubifs_tnc_get_bu_keys(c, bu);

	err = ubifs_tnc_get_bu_keys(c, bu);

	if (err)

	if (err)

		goto out_warn;

		goto out_warn;
@@ -735,12 +725,25 @@ static int ubifs_do_bulk_read(struct ubifs_info *c, struct page *page1) 
		 * together. If all the pages were like this, bulk-read would

		 * together. If all the pages were like this, bulk-read would

		 * reduce performance, so we turn it off for a while.

		 * reduce performance, so we turn it off for a while.

		 */

		 */

		ui->read_in_a_row = 0;

		goto out_bu_off;

		ui->bulk_read = 0;

		goto out_free;

	}

	}





	if (bu->cnt) {

	if (bu->cnt) {

		if (allocate) {

			/*

			 * Allocate bulk-read buffer depending on how many data

			 * nodes we are going to read.

			 */

			bu->buf_len = bu->zbranch[bu->cnt - 1].offs +

				      bu->zbranch[bu->cnt - 1].len -

				      bu->zbranch[0].offs;

			ubifs_assert(bu->buf_len > 0);

			ubifs_assert(bu->buf_len <= c->leb_size);

			bu->buf = kmalloc(bu->buf_len, GFP_NOFS | __GFP_NOWARN);

			if (!bu->buf)

				goto out_bu_off;

		}



		err = ubifs_tnc_bulk_read(c, bu);

		err = ubifs_tnc_bulk_read(c, bu);

		if (err)

		if (err)

			goto out_warn;

			goto out_warn;
@@ -779,13 +782,17 @@ static int ubifs_do_bulk_read(struct ubifs_info *c, struct page *page1) 
	ui->last_page_read = offset + page_idx - 1;

	ui->last_page_read = offset + page_idx - 1;





out_free:

out_free:

	if (allocate)

		kfree(bu->buf);

		kfree(bu->buf);

	kfree(bu);

	return ret;

	return ret;





out_warn:

out_warn:

	ubifs_warn("ignoring error %d and skipping bulk-read", err);

	ubifs_warn("ignoring error %d and skipping bulk-read", err);

	goto out_free;

	goto out_free;



out_bu_off:

	ui->read_in_a_row = ui->bulk_read = 0;

	goto out_free;

}

}





/**

/**
@@ -803,18 +810,20 @@ static int ubifs_bulk_read(struct page *page) 
	struct ubifs_info *c = inode->i_sb->s_fs_info;

	struct ubifs_info *c = inode->i_sb->s_fs_info;

	struct ubifs_inode *ui = ubifs_inode(inode);

	struct ubifs_inode *ui = ubifs_inode(inode);

	pgoff_t index = page->index, last_page_read = ui->last_page_read;

	pgoff_t index = page->index, last_page_read = ui->last_page_read;

	int ret = 0;

	struct bu_info *bu;

	int err = 0;





	ui->last_page_read = index;

	ui->last_page_read = index;



	if (!c->bulk_read)

	if (!c->bulk_read)

		return 0;

		return 0;



	/*

	/*

	 * Bulk-read is protected by ui_mutex, but it is an optimization, so

	 * Bulk-read is protected by ui_mutex, but it is an optimization, so

	 * don't bother if we cannot lock the mutex.

	 * don't bother if we cannot lock the mutex.

	 */

	 */

	if (!mutex_trylock(&ui->ui_mutex))

	if (!mutex_trylock(&ui->ui_mutex))

		return 0;

		return 0;



	if (index != last_page_read + 1) {

	if (index != last_page_read + 1) {

		/* Turn off bulk-read if we stop reading sequentially */

		/* Turn off bulk-read if we stop reading sequentially */

		ui->read_in_a_row = 1;

		ui->read_in_a_row = 1;
@@ -822,6 +831,7 @@ static int ubifs_bulk_read(struct page *page) 
			ui->bulk_read = 0;

			ui->bulk_read = 0;

		goto out_unlock;

		goto out_unlock;

	}

	}



	if (!ui->bulk_read) {

	if (!ui->bulk_read) {

		ui->read_in_a_row += 1;

		ui->read_in_a_row += 1;

		if (ui->read_in_a_row < 3)

		if (ui->read_in_a_row < 3)
@@ -829,10 +839,22 @@ static int ubifs_bulk_read(struct page *page) 
		/* Three reads in a row, so switch on bulk-read */

		/* Three reads in a row, so switch on bulk-read */

		ui->bulk_read = 1;

		ui->bulk_read = 1;

	}

	}

	ret = ubifs_do_bulk_read(c, page);



	bu = kmalloc(sizeof(struct bu_info), GFP_NOFS | __GFP_NOWARN);

	if (!bu)

		return 0;



	bu->buf = NULL;

	bu->buf_len = c->max_bu_buf_len;

	data_key_init(c, &bu->key, inode->i_ino,

		      page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT);



	err = ubifs_do_bulk_read(c, bu, page);

	kfree(bu);



out_unlock:

out_unlock:

	mutex_unlock(&ui->ui_mutex);

	mutex_unlock(&ui->ui_mutex);

	return ret;

	return err;

}

}





static int ubifs_readpage(struct file *file, struct page *page)

static int ubifs_readpage(struct file *file, struct page *page)

fs/ubifs/super.c

+6 −6
Original line number Original line Diff line number Diff line
@@ -569,16 +569,16 @@ static int init_constants_early(struct ubifs_info *c) 
	c->leb_overhead = c->leb_size % UBIFS_MAX_DATA_NODE_SZ;

	c->leb_overhead = c->leb_size % UBIFS_MAX_DATA_NODE_SZ;





	/* Buffer size for bulk-reads */

	/* Buffer size for bulk-reads */

	c->bulk_read_buf_size = UBIFS_MAX_BULK_READ * UBIFS_MAX_DATA_NODE_SZ;

	c->max_bu_buf_len = UBIFS_MAX_BULK_READ * UBIFS_MAX_DATA_NODE_SZ;

	if (c->bulk_read_buf_size > c->leb_size)

	if (c->max_bu_buf_len > c->leb_size)

		c->bulk_read_buf_size = c->leb_size;

		c->max_bu_buf_len = c->leb_size;

	if (c->bulk_read_buf_size > UBIFS_KMALLOC_OK) {

	if (c->max_bu_buf_len > UBIFS_KMALLOC_OK) {

		/* Check if we can kmalloc that much */

		/* Check if we can kmalloc that much */

		void *try = kmalloc(c->bulk_read_buf_size,

		void *try = kmalloc(c->max_bu_buf_len,

				    GFP_KERNEL | __GFP_NOWARN);

				    GFP_KERNEL | __GFP_NOWARN);

		kfree(try);

		kfree(try);

		if (!try)

		if (!try)

			c->bulk_read_buf_size = UBIFS_KMALLOC_OK;

			c->max_bu_buf_len = UBIFS_KMALLOC_OK;

	}

	}

	return 0;

	return 0;

}

}

fs/ubifs/tnc.c

+6 −1
Original line number Original line Diff line number Diff line
@@ -1501,7 +1501,12 @@ int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key, 
 * @bu: bulk-read parameters and results

 * @bu: bulk-read parameters and results

 *

 *

 * Lookup consecutive data node keys for the same inode that reside

 * Lookup consecutive data node keys for the same inode that reside

 * consecutively in the same LEB.

 * consecutively in the same LEB. This function returns zero in case of success

 * and a negative error code in case of failure.

 *

 * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function

 * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares

 * maxumum possible amount of nodes for bulk-read.

 */

 */

int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)

int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)

{

{

fs/ubifs/ubifs.h

+2 −2
Original line number Original line Diff line number Diff line
@@ -969,7 +969,7 @@ struct ubifs_mount_opts { 
 * @mst_node: master node

 * @mst_node: master node

 * @mst_offs: offset of valid master node

 * @mst_offs: offset of valid master node

 * @mst_mutex: protects the master node area, @mst_node, and @mst_offs

 * @mst_mutex: protects the master node area, @mst_node, and @mst_offs

 * @bulk_read_buf_size: buffer size for bulk-reads

 * @max_bu_buf_len: maximum bulk-read buffer length

 *

 *

 * @log_lebs: number of logical eraseblocks in the log

 * @log_lebs: number of logical eraseblocks in the log

 * @log_bytes: log size in bytes

 * @log_bytes: log size in bytes
@@ -1217,7 +1217,7 @@ struct ubifs_info { 
	struct ubifs_mst_node *mst_node;

	struct ubifs_mst_node *mst_node;

	int mst_offs;

	int mst_offs;

	struct mutex mst_mutex;

	struct mutex mst_mutex;

	int bulk_read_buf_size;

	int max_bu_buf_len;





	int log_lebs;

	int log_lebs;

	long long log_bytes;

	long long log_bytes;