diff options
Diffstat (limited to 'Documentation/block')
-rw-r--r-- | Documentation/block/as-iosched.txt | 4 | ||||
-rw-r--r-- | Documentation/block/barrier.txt | 6 | ||||
-rw-r--r-- | Documentation/block/biodoc.txt | 10 | ||||
-rw-r--r-- | Documentation/block/deadline-iosched.txt | 4 |
4 files changed, 12 insertions, 12 deletions
diff --git a/Documentation/block/as-iosched.txt b/Documentation/block/as-iosched.txt index 6f47332c883..e2a66f8143c 100644 --- a/Documentation/block/as-iosched.txt +++ b/Documentation/block/as-iosched.txt @@ -99,8 +99,8 @@ contrast, many write requests may be dispatched to the disk controller at a time during a write batch. It is this characteristic that can make the anticipatory scheduler perform anomalously with controllers supporting TCQ, or with hardware striped RAID devices. Setting the antic_expire -queue paramter (see below) to zero disables this behavior, and the anticipatory -scheduler behaves essentially like the deadline scheduler. +queue parameter (see below) to zero disables this behavior, and the +anticipatory scheduler behaves essentially like the deadline scheduler. When read anticipation is enabled (antic_expire is not zero), reads are dispatched to the disk controller one at a time. diff --git a/Documentation/block/barrier.txt b/Documentation/block/barrier.txt index 03971518b22..a272c3db809 100644 --- a/Documentation/block/barrier.txt +++ b/Documentation/block/barrier.txt @@ -25,7 +25,7 @@ of the following three ways. i. For devices which have queue depth greater than 1 (TCQ devices) and support ordered tags, block layer can just issue the barrier as an ordered request and the lower level driver, controller and drive -itself are responsible for making sure that the ordering contraint is +itself are responsible for making sure that the ordering constraint is met. Most modern SCSI controllers/drives should support this. NOTE: SCSI ordered tag isn't currently used due to limitation in the @@ -42,7 +42,7 @@ iii. Devices which have queue depth of 1. This is a degenerate case of ii. Just keeping issue order suffices. Ancient SCSI controllers/drives and IDE drives are in this category. -2. Forced flushing to physcial medium +2. Forced flushing to physical medium Again, if you're not gonna do synchronization with disk drives (dang, it sounds even more appealing now!), the reason you use I/O barriers @@ -56,7 +56,7 @@ There are four cases, i. No write-back cache. Keeping requests ordered is enough. ii. Write-back cache but no flush operation. There's no way to -gurantee physical-medium commit order. This kind of devices can't to +guarantee physical-medium commit order. This kind of devices can't to I/O barriers. iii. Write-back cache and flush operation but no FUA (forced unit diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt index f989a9e839b..34bf8f60d8f 100644 --- a/Documentation/block/biodoc.txt +++ b/Documentation/block/biodoc.txt @@ -135,7 +135,7 @@ Some new queue property settings: Sets two variables that limit the size of the request. - The request queue's max_sectors, which is a soft size in - in units of 512 byte sectors, and could be dynamically varied + units of 512 byte sectors, and could be dynamically varied by the core kernel. - The request queue's max_hw_sectors, which is a hard limit @@ -783,7 +783,7 @@ all the outstanding requests. There's a third helper to do that: blk_queue_invalidate_tags(request_queue_t *q) - Clear the internal block tag queue and readd all the pending requests + Clear the internal block tag queue and re-add all the pending requests to the request queue. The driver will receive them again on the next request_fn run, just like it did the first time it encountered them. @@ -890,7 +890,7 @@ Aside: Kvec i/o: - Ben LaHaise's aio code uses a slighly different structure instead + Ben LaHaise's aio code uses a slightly different structure instead of kiobufs, called a kvec_cb. This contains an array of <page, offset, len> tuples (very much like the networking code), together with a callback function and data pointer. This is embedded into a brw_cb structure when passed @@ -988,7 +988,7 @@ elevator_exit_fn Allocate and free any elevator specific storage for a queue. 4.2 Request flows seen by I/O schedulers -All requests seens by I/O schedulers strictly follow one of the following three +All requests seen by I/O schedulers strictly follow one of the following three flows. set_req_fn -> @@ -1203,6 +1203,6 @@ temporarily map a bio into the virtual address space. and Linus' comments - Jan 2001) 9.2 Discussions about kiobuf and bh design on lkml between sct, linus, alan et al - Feb-March 2001 (many of the initial thoughts that led to bio were -brought up in this discusion thread) +brought up in this discussion thread) 9.3 Discussions on mempool on lkml - Dec 2001. diff --git a/Documentation/block/deadline-iosched.txt b/Documentation/block/deadline-iosched.txt index c918b3a6022..be08ffd1e9b 100644 --- a/Documentation/block/deadline-iosched.txt +++ b/Documentation/block/deadline-iosched.txt @@ -23,11 +23,11 @@ you can do so by typing: read_expire (in ms) ----------- -The goal of the deadline io scheduler is to attempt to guarentee a start +The goal of the deadline io scheduler is to attempt to guarantee a start service time for a request. As we focus mainly on read latencies, this is tunable. When a read request first enters the io scheduler, it is assigned a deadline that is the current time + the read_expire value in units of -miliseconds. +milliseconds. write_expire (in ms) |