kernel/linux.git/include/linux/blkdev.h, branch v3.6.6

block: disable discard request merge temporarily

2012-08-09T13:20:23+00:00

The SCSI discard request merge never worked, and looks no solution for in future, let's disable it temporarily. Signed-off-by: Shaohua Li Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: Add blk_bio_map_sg() helper

2012-08-02T21:42:04+00:00

Add a helper to map a bio to a scatterlist, modelled after blk_rq_map_sg. This helper is useful for any driver that wants to create a scatterlist from its ->make_request_fn method. Changes in v2: - Use __blk_segment_map_sg to avoid duplicated code - Add cocbook style function comment Cc: Rusty Russell Cc: Christoph Hellwig Cc: Tejun Heo Cc: Shaohua Li Cc: "Michael S. Tsirkin" Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: virtualization@lists.linux-foundation.org Signed-off-by: Christoph Hellwig Signed-off-by: Minchan Kim Signed-off-by: Asias He Signed-off-by: Jens Axboe

block: split discard into aligned requests

2012-08-02T07:48:50+00:00

When a disk has large discard_granularity and small max_discard_sectors, discards are not split with optimal alignment. In the limit case of discard_granularity == max_discard_sectors, no request could be aligned correctly, so in fact you might end up with no discarded logical blocks at all. Another example that helps showing the condition in the patch is with discard_granularity == 64, max_discard_sectors == 128. A request that is submitted for 256 sectors 2..257 will be split in two: 2..129, 130..257. However, only 2 aligned blocks out of 3 are included in the request; 128..191 may be left intact and not discarded. With this patch, the first request will be truncated to ensure good alignment of what's left, and the split will be 2..127, 128..255, 256..257. The patch will also take into account the discard_alignment. At most one extra request will be introduced, because the first request will be reduced by at most granularity-1 sectors, and granularity must be less than max_discard_sectors. Subsequent requests will run on round_down(max_discard_sectors, granularity) sectors, as in the current code. Signed-off-by: Paolo Bonzini Acked-by: Vivek Goyal Tested-by: Mike Snitzer Signed-off-by: Jens Axboe

blk: pass from_schedule to non-request unplug functions.

2012-07-31T07:08:15+00:00

This will allow md/raid to know why the unplug was called, and will be able to act according - if !from_schedule it is safe to perform tasks which could themselves schedule. Signed-off-by: NeilBrown Signed-off-by: Jens Axboe

blk: centralize non-request unplug handling.

2012-07-31T07:08:14+00:00

Both md and umem has similar code for getting notified on an blk_finish_plug event. Centralize this code in block/ and allow each driver to provide its distinctive difference. Signed-off-by: NeilBrown Signed-off-by: Jens Axboe

blkcg: implement per-blkg request allocation

2012-06-26T22:42:49+00:00

Currently, request_queue has one request_list to allocate requests from regardless of blkcg of the IO being issued. When the unified request pool is used up, cfq proportional IO limits become meaningless - whoever grabs the next request being freed wins the race regardless of the configured weights. This can be easily demonstrated by creating a blkio cgroup w/ very low weight, put a program which can issue a lot of random direct IOs there and running a sequential IO from a different cgroup. As soon as the request pool is used up, the sequential IO bandwidth crashes. This patch implements per-blkg request_list. Each blkg has its own request_list and any IO allocates its request from the matching blkg making blkcgs completely isolated in terms of request allocation. * Root blkcg uses the request_list embedded in each request_queue, which was renamed to @q->root_rl from @q->rq. While making blkcg rl handling a bit harier, this enables avoiding most overhead for root blkcg. * Queue fullness is properly per request_list but bdi isn't blkcg aware yet, so congestion state currently just follows the root blkcg. As writeback isn't aware of blkcg yet, this works okay for async congestion but readahead may get the wrong signals. It's better than blkcg completely collapsing with shared request_list but needs to be improved with future changes. * After this change, each block cgroup gets a full request pool making resource consumption of each cgroup higher. This makes allowing non-root users to create cgroups less desirable; however, note that allowing non-root users to directly manage cgroups is already severely broken regardless of this patch - each block cgroup consumes kernel memory and skews IO weight (IO weights are not hierarchical). v2: queue-sysfs.txt updated and patch description udpated as suggested by Vivek. v3: blk_get_rl() wasn't checking error return from blkg_lookup_create() and may cause oops on lookup failure. Fix it by falling back to root_rl on blkg lookup failures. This problem was spotted by Rakesh Iyer . v4: Updated to accomodate 458f27a982 "block: Avoid missed wakeup in request waitqueue". blk_drain_queue() now wakes up waiters on all blkg->rl on the target queue. Signed-off-by: Tejun Heo Acked-by: Vivek Goyal Cc: Wu Fengguang Signed-off-by: Jens Axboe

block: prepare for multiple request_lists

2012-06-25T09:53:52+00:00

Request allocation is about to be made per-blkg meaning that there'll be multiple request lists. * Make queue full state per request_list. blk_*queue_full() functions are renamed to blk_*rl_full() and takes @rl instead of @q. * Rename blk_init_free_list() to blk_init_rl() and make it take @rl instead of @q. Also add @gfp_mask parameter. * Add blk_exit_rl() instead of destroying rl directly from blk_release_queue(). * Add request_list->q and make request alloc/free functions - blk_free_request(), [__]freed_request(), __get_request() - take @rl instead of @q. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo Acked-by: Vivek Goyal Signed-off-by: Jens Axboe

block: add q->nr_rqs[] and move q->rq.elvpriv to q->nr_rqs_elvpriv

2012-06-25T09:53:51+00:00

Add q->nr_rqs[] which currently behaves the same as q->rq.count[] and move q->rq.elvpriv to q->nr_rqs_elvpriv. blk_drain_queue() is updated to use q->nr_rqs[] instead of q->rq.count[]. These counters separates queue-wide request statistics from the request list and allow implementation of per-queue request allocation. While at it, properly indent fields of struct request_list. Signed-off-by: Tejun Heo Acked-by: Vivek Goyal Signed-off-by: Jens Axboe

block: Drop dead function blk_abort_queue()

2012-06-15T06:46:23+00:00

This function was only used by btrfs code in btrfs_abort_devices() (seems in a wrong way). It was removed in commit d07eb9117050c9ed3f78296ebcc06128b52693be, So, Let's remove the dead code to avoid any confusion. Changes in v2: update commit log, btrfs_abort_devices() was removed already. Cc: Jens Axboe Cc: linux-kernel@vger.kernel.org Cc: Chris Mason Cc: linux-btrfs@vger.kernel.org Cc: David Sterba Signed-off-by: Asias He Signed-off-by: Jens Axboe

Merge branch 'for-3.5/core' of git://git.kernel.dk/linux-block

2012-05-30T15:52:42+00:00

Merge block/IO core bits from Jens Axboe: "This is a bit bigger on the core side than usual, but that is purely because we decided to hold off on parts of Tejun's submission on 3.4 to give it a bit more time to simmer. As a consequence, it's seen a long cycle in for-next. It contains: - Bug fix from Dan, wrong locking type. - Relax splice gifting restriction from Eric. - A ton of updates from Tejun, primarily for blkcg. This improves the code a lot, making the API nicer and cleaner, and also includes fixes for how we handle and tie policies and re-activate on switches. The changes also include generic bug fixes. - A simple fix from Vivek, along with a fix for doing proper delayed allocation of the blkcg stats." Fix up annoying conflict just due to different merge resolution in Documentation/feature-removal-schedule.txt * 'for-3.5/core' of git://git.kernel.dk/linux-block: (92 commits) blkcg: tg_stats_alloc_lock is an irq lock vmsplice: relax alignement requirements for SPLICE_F_GIFT blkcg: use radix tree to index blkgs from blkcg blkcg: fix blkcg->css ref leak in __blkg_lookup_create() block: fix elvpriv allocation failure handling block: collapse blk_alloc_request() into get_request() blkcg: collapse blkcg_policy_ops into blkcg_policy blkcg: embed struct blkg_policy_data in policy specific data blkcg: mass rename of blkcg API blkcg: style cleanups for blk-cgroup.h blkcg: remove blkio_group->path[] blkcg: blkg_rwstat_read() was missing inline blkcg: shoot down blkgs if all policies are deactivated blkcg: drop stuff unused after per-queue policy activation update blkcg: implement per-queue policy activation blkcg: add request_queue->root_blkg blkcg: make request_queue bypassing on allocation blkcg: make sure blkg_lookup() returns %NULL if @q is bypassing blkcg: make blkg_conf_prep() take @pol and return with queue lock held blkcg: remove static policy ID enums ...