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Commit 86adf8ad authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block 

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: add text file detailing queue/ sysfs files
  bio.h: If they MUST be inlined, then use __always_inline
  Fix misleading comment in bio.h
  block: fix inconsistent parenthesisation of QUEUE_FLAG_DEFAULT
  block: fix oops in blk_queue_io_stat()
parents 3fff0179 cbb5901b

Documentation/block/queue-sysfs.txt

0 → 100644
+63 −0
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Queue sysfs files

=================



This text file will detail the queue files that are located in the sysfs tree

for each block device. Note that stacked devices typically do not export

any settings, since their queue merely functions are a remapping target.

These files are the ones found in the /sys/block/xxx/queue/ directory.



Files denoted with a RO postfix are readonly and the RW postfix means

read-write.



hw_sector_size (RO)

-------------------

This is the hardware sector size of the device, in bytes.



max_hw_sectors_kb (RO)

----------------------

This is the maximum number of kilobytes supported in a single data transfer.



max_sectors_kb (RW)

-------------------

This is the maximum number of kilobytes that the block layer will allow

for a filesystem request. Must be smaller than or equal to the maximum

size allowed by the hardware.



nomerges (RW)

-------------

This enables the user to disable the lookup logic involved with IO merging

requests in the block layer. Merging may still occur through a direct

1-hit cache, since that comes for (almost) free. The IO scheduler will not

waste cycles doing tree/hash lookups for merges if nomerges is 1. Defaults

to 0, enabling all merges.



nr_requests (RW)

----------------

This controls how many requests may be allocated in the block layer for

read or write requests. Note that the total allocated number may be twice

this amount, since it applies only to reads or writes (not the accumulated

sum).



read_ahead_kb (RW)

------------------

Maximum number of kilobytes to read-ahead for filesystems on this block

device.



rq_affinity (RW)

----------------

If this option is enabled, the block layer will migrate request completions

to the CPU that originally submitted the request. For some workloads

this provides a significant reduction in CPU cycles due to caching effects.



scheduler (RW)

--------------

When read, this file will display the current and available IO schedulers

for this block device. The currently active IO scheduler will be enclosed

in [] brackets. Writing an IO scheduler name to this file will switch

control of this block device to that new IO scheduler. Note that writing

an IO scheduler name to this file will attempt to load that IO scheduler

module, if it isn't already present in the system.







Jens Axboe <jens.axboe@oracle.com>, February 2009

block/blk-core.c

+3 −3
Original line number Diff line number Diff line
@@ -69,7 +69,7 @@ static void drive_stat_acct(struct request *rq, int new_io) 
	int rw = rq_data_dir(rq);

	int cpu;



	if (!blk_fs_request(rq) || !disk || !blk_queue_io_stat(disk->queue))

	if (!blk_fs_request(rq) || !disk || !blk_do_io_stat(disk->queue))

		return;



	cpu = part_stat_lock();
@@ -1667,7 +1667,7 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes) 
{

	struct gendisk *disk = req->rq_disk;



	if (!disk || !blk_queue_io_stat(disk->queue))

	if (!disk || !blk_do_io_stat(disk->queue))

		return;



	if (blk_fs_request(req)) {
@@ -1686,7 +1686,7 @@ static void blk_account_io_done(struct request *req) 
{

	struct gendisk *disk = req->rq_disk;



	if (!disk || !blk_queue_io_stat(disk->queue))

	if (!disk || !blk_do_io_stat(disk->queue))

		return;



	/*

block/blk.h

+8 −0
Original line number Diff line number Diff line
@@ -108,4 +108,12 @@ static inline int blk_cpu_to_group(int cpu) 
#endif

}



static inline int blk_do_io_stat(struct request_queue *q)

{

	if (q)

		return blk_queue_io_stat(q);



	return 0;

}



#endif

include/linux/bio.h

+6 −4
Original line number Diff line number Diff line
@@ -451,12 +451,13 @@ extern struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly; 


#ifdef CONFIG_HIGHMEM

/*

 * remember to add offset! and never ever reenable interrupts between a

 * bvec_kmap_irq and bvec_kunmap_irq!!

 * remember never ever reenable interrupts between a bvec_kmap_irq and

 * bvec_kunmap_irq!

 *

 * This function MUST be inlined - it plays with the CPU interrupt flags.

 */

static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)

static __always_inline char *bvec_kmap_irq(struct bio_vec *bvec,

		unsigned long *flags)

{

	unsigned long addr;
@@ -472,7 +473,8 @@ static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags) 
	return (char *) addr + bvec->bv_offset;

}



static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)

static __always_inline void bvec_kunmap_irq(char *buffer,

		unsigned long *flags)

{

	unsigned long ptr = (unsigned long) buffer & PAGE_MASK;

include/linux/blkdev.h

+1 −1
Original line number Diff line number Diff line
@@ -455,7 +455,7 @@ struct request_queue 


#define QUEUE_FLAG_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\

				 (1 << QUEUE_FLAG_CLUSTER) |		\

				  1 << QUEUE_FLAG_STACKABLE)

				 (1 << QUEUE_FLAG_STACKABLE))



static inline int queue_is_locked(struct request_queue *q)

{