Commit 3fcfab16 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
Browse files

[PATCH] separate bdi congestion functions from queue congestion functions 



Separate out the concept of "queue congestion" from "backing-dev congestion".
Congestion is a backing-dev concept, not a queue concept.

The blk_* congestion functions are retained, as wrappers around the core
backing-dev congestion functions.

This proper layering is needed so that NFS can cleanly use the congestion
functions, and so that CONFIG_BLOCK=n actually links.

Cc: "Thomas Maier" <balagi@justmail.de>
Cc: "Jens Axboe" <jens.axboe@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: David Howells <dhowells@redhat.com>
Cc: Peter Osterlund <petero2@telia.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 79e2de4b

arch/i386/lib/usercopy.c

+2 −1
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <linux/highmem.h>

#include <linux/blkdev.h>

#include <linux/module.h>

#include <linux/backing-dev.h>

#include <asm/uaccess.h>

#include <asm/mmx.h>
@@ -741,7 +742,7 @@ unsigned long __copy_to_user_ll(void __user *to, const void *from, 


			if (retval == -ENOMEM && is_init(current)) {

				up_read(&current->mm->mmap_sem);

				blk_congestion_wait(WRITE, HZ/50);

				congestion_wait(WRITE, HZ/50);

				goto survive;

			}

block/ll_rw_blk.c

+0 −71
Original line number Diff line number Diff line
@@ -56,11 +56,6 @@ static kmem_cache_t *requestq_cachep; 
 */

static kmem_cache_t *iocontext_cachep;



static wait_queue_head_t congestion_wqh[2] = {

		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),

		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])

	};



/*

 * Controlling structure to kblockd

 */
@@ -112,37 +107,6 @@ static void blk_queue_congestion_threshold(struct request_queue *q) 
	q->nr_congestion_off = nr;

}



/*

 * A queue has just exitted congestion.  Note this in the global counter of

 * congested queues, and wake up anyone who was waiting for requests to be

 * put back.

 */

void blk_clear_queue_congested(request_queue_t *q, int rw)

{

	enum bdi_state bit;

	wait_queue_head_t *wqh = &congestion_wqh[rw];



	bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested;

	clear_bit(bit, &q->backing_dev_info.state);

	smp_mb__after_clear_bit();

	if (waitqueue_active(wqh))

		wake_up(wqh);

}

EXPORT_SYMBOL(blk_clear_queue_congested);



/*

 * A queue has just entered congestion.  Flag that in the queue's VM-visible

 * state flags and increment the global gounter of congested queues.

 */

void blk_set_queue_congested(request_queue_t *q, int rw)

{

	enum bdi_state bit;



	bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested;

	set_bit(bit, &q->backing_dev_info.state);

}

EXPORT_SYMBOL(blk_set_queue_congested);



/**

 * blk_get_backing_dev_info - get the address of a queue's backing_dev_info

 * @bdev:	device
@@ -2755,41 +2719,6 @@ void blk_end_sync_rq(struct request *rq, int error) 
}

EXPORT_SYMBOL(blk_end_sync_rq);



/**

 * blk_congestion_wait - wait for a queue to become uncongested

 * @rw: READ or WRITE

 * @timeout: timeout in jiffies

 *

 * Waits for up to @timeout jiffies for a queue (any queue) to exit congestion.

 * If no queues are congested then just wait for the next request to be

 * returned.

 */

long blk_congestion_wait(int rw, long timeout)

{

	long ret;

	DEFINE_WAIT(wait);

	wait_queue_head_t *wqh = &congestion_wqh[rw];



	prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE);

	ret = io_schedule_timeout(timeout);

	finish_wait(wqh, &wait);

	return ret;

}



EXPORT_SYMBOL(blk_congestion_wait);



/**

 * blk_congestion_end - wake up sleepers on a congestion queue

 * @rw: READ or WRITE

 */

void blk_congestion_end(int rw)

{

	wait_queue_head_t *wqh = &congestion_wqh[rw];



	if (waitqueue_active(wqh))

		wake_up(wqh);

}



/*

 * Has to be called with the request spinlock acquired

 */

drivers/md/dm-crypt.c

+2 −1
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/slab.h>

#include <linux/crypto.h>

#include <linux/workqueue.h>

#include <linux/backing-dev.h>

#include <asm/atomic.h>

#include <linux/scatterlist.h>

#include <asm/page.h>
@@ -602,7 +603,7 @@ static void process_write(struct crypt_io *io) 


		/* out of memory -> run queues */

		if (remaining)

			blk_congestion_wait(bio_data_dir(clone), HZ/100);

			congestion_wait(bio_data_dir(clone), HZ/100);

	}

}

fs/fat/file.c

+2 −1
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/smp_lock.h>

#include <linux/buffer_head.h>

#include <linux/writeback.h>

#include <linux/backing-dev.h>

#include <linux/blkdev.h>



int fat_generic_ioctl(struct inode *inode, struct file *filp,
@@ -118,7 +119,7 @@ static int fat_file_release(struct inode *inode, struct file *filp) 
	if ((filp->f_mode & FMODE_WRITE) &&

	     MSDOS_SB(inode->i_sb)->options.flush) {

		fat_flush_inodes(inode->i_sb, inode, NULL);

		blk_congestion_wait(WRITE, HZ/10);

		congestion_wait(WRITE, HZ/10);

	}

	return 0;

}

fs/nfs/write.c

+3 −1
Original line number Diff line number Diff line
@@ -57,6 +57,8 @@ 
#include <linux/nfs_fs.h>

#include <linux/nfs_mount.h>

#include <linux/nfs_page.h>

#include <linux/backing-dev.h>



#include <asm/uaccess.h>

#include <linux/smp_lock.h>
@@ -395,7 +397,7 @@ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc) 
out:

	clear_bit(BDI_write_congested, &bdi->state);

	wake_up_all(&nfs_write_congestion);

	writeback_congestion_end();

	congestion_end(WRITE);

	return err;

}