diff options
| -rw-r--r-- | Documentation/block/queue-sysfs.txt | 63 | ||||
| -rw-r--r-- | block/blk-core.c | 6 | ||||
| -rw-r--r-- | block/blk.h | 8 | ||||
| -rw-r--r-- | include/linux/bio.h | 10 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 2 |
5 files changed, 81 insertions, 8 deletions
diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt new file mode 100644 index 00000000000..e164403f60e --- /dev/null +++ b/Documentation/block/queue-sysfs.txt @@ -0,0 +1,63 @@ +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 diff --git a/block/blk-core.c b/block/blk-core.c index ca69f3d9410..29bcfac6c68 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -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; /* diff --git a/block/blk.h b/block/blk.h index 6e1ed40534e..0dce92c3749 100644 --- a/block/blk.h +++ b/block/blk.h @@ -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 diff --git a/include/linux/bio.h b/include/linux/bio.h index 0942765cf8c..2aa283ab062 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -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; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index d08c4b8219a..dcaa0fd84b0 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -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) { |