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* block: fix bogus EFAULT error from SG_IO ioctlPaolo Bonzini2015-06-271-2/+2
| | | | | | | | | | | | | | | Whenever blk_fill_sghdr_rq fails, its errno code is ignored and changed to EFAULT. This can cause very confusing errors: $ sg_persist -k /dev/sda persistent reservation in: pass through os error: Bad address The fix is trivial, just propagate the return value from blk_fill_sghdr_rq. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* Merge tag 'dm-4.2-fixes' of ↵Linus Torvalds2015-06-261-11/+83
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper fixes from Mike Snitzer: "Apologies for not pressing this request-based DM partial completion issue further, it was an oversight on my part. We'll have to get it fixed up properly and revisit for a future release. - Revert block and DM core changes the removed request-based DM's ability to handle partial request completions -- otherwise with the current SCSI LLDs these changes could lead to silent data corruption. - Fix two DM version bumps that were missing from the initial 4.2 DM pull request (enabled userspace lvm2 to know certain changes have been made)" * tag 'dm-4.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm cache policy smq: fix "default" version to be 1.4.0 dm: bump the ioctl version to 4.32.0 Revert "block, dm: don't copy bios for request clones" Revert "dm: do not allocate any mempools for blk-mq request-based DM"
| * Revert "block, dm: don't copy bios for request clones"Mike Snitzer2015-06-261-11/+83
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 5f1b670d0bef508a5554d92525f5f6d00d640b38. Justification for revert as reported in this dm-devel post: https://www.redhat.com/archives/dm-devel/2015-June/msg00160.html this change should not be pushed to mainline yet. Firstly, Christoph has a newer version of the patch that fixes silent data corruption problem: https://www.redhat.com/archives/dm-devel/2015-May/msg00229.html And the new version still depends on LLDDs to always complete requests to the end when error happens, while block API doesn't enforce such a requirement. If the assumption is ever broken, the inconsistency between request and bio (e.g. rq->__sector and rq->bio) will cause silent data corruption: https://www.redhat.com/archives/dm-devel/2015-June/msg00022.html Reported-by: Junichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
| * Merge remote-tracking branch 'jens/for-4.2/core' into dm-4.2Mike Snitzer2015-05-298-212/+208
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* | \ Merge branch 'for-4.2/writeback' of git://git.kernel.dk/linux-blockLinus Torvalds2015-06-2511-728/+139
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull cgroup writeback support from Jens Axboe: "This is the big pull request for adding cgroup writeback support. This code has been in development for a long time, and it has been simmering in for-next for a good chunk of this cycle too. This is one of those problems that has been talked about for at least half a decade, finally there's a solution and code to go with it. Also see last weeks writeup on LWN: http://lwn.net/Articles/648292/" * 'for-4.2/writeback' of git://git.kernel.dk/linux-block: (85 commits) writeback, blkio: add documentation for cgroup writeback support vfs, writeback: replace FS_CGROUP_WRITEBACK with SB_I_CGROUPWB writeback: do foreign inode detection iff cgroup writeback is enabled v9fs: fix error handling in v9fs_session_init() bdi: fix wrong error return value in cgwb_create() buffer: remove unusued 'ret' variable writeback: disassociate inodes from dying bdi_writebacks writeback: implement foreign cgroup inode bdi_writeback switching writeback: add lockdep annotation to inode_to_wb() writeback: use unlocked_inode_to_wb transaction in inode_congested() writeback: implement unlocked_inode_to_wb transaction and use it for stat updates writeback: implement [locked_]inode_to_wb_and_lock_list() writeback: implement foreign cgroup inode detection writeback: make writeback_control track the inode being written back writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb() mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use writeback: implement memcg writeback domain based throttling writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes writeback: implement memcg wb_domain writeback: update wb_over_bg_thresh() to use wb_domain aware operations ...
| * | | writeback, blkcg: propagate non-root blkcg congestion stateTejun Heo2015-06-021-6/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that bdi layer can handle per-blkcg bdi_writeback_congested state, blk_{set|clear}_congested() can propagate non-root blkcg congestion state to them. This can be easily achieved by disabling the root_rl tests in blk_{set|clear}_congested(). Note that we still need those tests when !CONFIG_CGROUP_WRITEBACK as otherwise we'll end up flipping root blkcg wb's congestion state for events happening on other blkcgs. v2: Updated for bdi_writeback_congested. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | writeback, blkcg: restructure blk_{set|clear}_queue_congested()Tejun Heo2015-06-021-25/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blk_{set|clear}_queue_congested() take @q and set or clear, respectively, the congestion state of its bdi's root wb. Because bdi used to be able to handle congestion state only on the root wb, the callers of those functions tested whether the congestion is on the root blkcg and skipped if not. This is cumbersome and makes implementation of per cgroup bdi_writeback congestion state propagation difficult. This patch renames blk_{set|clear}_queue_congested() to blk_{set|clear}_congested(), and makes them take request_list instead of request_queue and test whether the specified request_list is the root one before updating bdi_writeback congestion state. This makes the tests in the callers unnecessary and simplifies them. As there are no external users of these functions, the definitions are moved from include/linux/blkdev.h to block/blk-core.c. This patch doesn't introduce any noticeable behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | writeback, blkcg: associate each blkcg_gq with the corresponding ↵Tejun Heo2015-06-021-2/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bdi_writeback_congested A blkg (blkcg_gq) can be congested and decongested independently from other blkgs on the same request_queue. Accordingly, for cgroup writeback support, the congestion status at bdi (backing_dev_info) should be split and updated separately from matching blkg's. This patch prepares by adding blkg->wb_congested and associating a blkg with its matching per-blkcg bdi_writeback_congested on creation. v2: Updated to associate bdi_writeback_congested instead of bdi_writeback. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | writeback: make backing_dev_info host cgroup-specific bdi_writebacksTejun Heo2015-06-021-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For the planned cgroup writeback support, on each bdi (backing_dev_info), each memcg will be served by a separate wb (bdi_writeback). This patch updates bdi so that a bdi can host multiple wbs (bdi_writebacks). On the default hierarchy, blkcg implicitly enables memcg. This allows using memcg's page ownership for attributing writeback IOs, and every memcg - blkcg combination can be served by its own wb by assigning a dedicated wb to each memcg. This means that there may be multiple wb's of a bdi mapped to the same blkcg. As congested state is per blkcg - bdi combination, those wb's should share the same congested state. This is achieved by tracking congested state via bdi_writeback_congested structs which are keyed by blkcg. bdi->wb remains unchanged and will keep serving the root cgroup. cgwb's (cgroup wb's) for non-root cgroups are created on-demand or looked up while dirtying an inode according to the memcg of the page being dirtied or current task. Each cgwb is indexed on bdi->cgwb_tree by its memcg id. Once an inode is associated with its wb, it can be retrieved using inode_to_wb(). Currently, none of the filesystems has FS_CGROUP_WRITEBACK and all pages will keep being associated with bdi->wb. v3: inode_attach_wb() in account_page_dirtied() moved inside mapping_cap_account_dirty() block where it's known to be !NULL. Also, an unnecessary NULL check before kfree() removed. Both detected by the kbuild bot. v2: Updated so that wb association is per inode and wb is per memcg rather than blkcg. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: kbuild test robot <fengguang.wu@intel.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | writeback: add {CONFIG|BDI_CAP|FS}_CGROUP_WRITEBACKTejun Heo2015-06-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup writeback requires support from both bdi and filesystem sides. Add BDI_CAP_CGROUP_WRITEBACK and FS_CGROUP_WRITEBACK to indicate support and enable BDI_CAP_CGROUP_WRITEBACK on block based bdi's by default. Also, define CONFIG_CGROUP_WRITEBACK which is enabled if both MEMCG and BLK_CGROUP are enabled. inode_cgwb_enabled() which determines whether a given inode's both bdi and fs support cgroup writeback is added. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | writeback: separate out include/linux/backing-dev-defs.hTejun Heo2015-06-024-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the planned cgroup writeback support, backing-dev related declarations will be more widely used across block and cgroup; unfortunately, including backing-dev.h from include/linux/blkdev.h makes cyclic include dependency quite likely. This patch separates out backing-dev-defs.h which only has the essential definitions and updates blkdev.h to include it. c files which need access to more backing-dev details now include backing-dev.h directly. This takes backing-dev.h off the common include dependency chain making it a lot easier to use it across block and cgroup. v2: fs/fat build failure fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | writeback: move backing_dev_info->state into bdi_writebackTejun Heo2015-06-021-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback) and the role of the separation is unclear. For cgroup support for writeback IOs, a bdi will be updated to host multiple wb's where each wb serves writeback IOs of a different cgroup on the bdi. To achieve that, a wb should carry all states necessary for servicing writeback IOs for a cgroup independently. This patch moves bdi->state into wb. * enum bdi_state is renamed to wb_state and the prefix of all enums is changed from BDI_ to WB_. * Explicit zeroing of bdi->state is removed without adding zeoring of wb->state as the whole data structure is zeroed on init anyway. * As there's still only one bdi_writeback per backing_dev_info, all uses of bdi->state are mechanically replaced with bdi->wb.state introducing no behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: drbd-dev@lists.linbit.com Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blkcg: implement bio_associate_blkcg()Tejun Heo2015-06-021-1/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, a bio can only be associated with the io_context and blkcg of %current using bio_associate_current(). This is too restrictive for cgroup writeback support. Implement bio_associate_blkcg() which associates a bio with the specified blkcg. bio_associate_blkcg() leaves the io_context unassociated. bio_associate_current() is updated so that it considers a bio as already associated if it has a blkcg_css, instead of an io_context, associated with it. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | cgroup, block: implement task_get_css() and use it in bio_associate_current()Tejun Heo2015-06-021-10/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bio_associate_current() currently open codes task_css() and css_tryget_online() to find and pin $current's blkcg css. Abstract it into task_get_css() which is implemented from cgroup side. As a task is always associated with an online css for every subsystem except while the css_set update is propagating, task_get_css() retries till css_tryget_online() succeeds. This is a cleanup and shouldn't lead to noticeable behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blkcg: add blkcg_root_cssTejun Heo2015-06-021-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add global constant blkcg_root_css which points to &blkcg_root.css. This will be used by cgroup writeback support. If blkcg is disabled, it's defined as ERR_PTR(-EINVAL). v2: The declarations moved to include/linux/blk-cgroup.h as suggested by Vivek. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blkcg: always create the blkcg_gq for the root blkcgTejun Heo2015-06-021-55/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, blkcg does a minor optimization where the root blkcg is created when the first blkcg policy is activated on a queue and destroyed on the deactivation of the last. On systems where blkcg is configured but not used, this saves one blkcg_gq struct per queue. On systems where blkcg is actually used, there's no difference. The only case where this can lead to any meaninful, albeit still minute, save in memory consumption is when all blkcg policies are deactivated after being widely used in the system, which is a hihgly unlikely scenario. The conditional existence of root blkcg_gq has already created several bugs in blkcg and became an issue once again for the new per-cgroup wb_congested mechanism for cgroup writeback support leading to a NULL dereference when no blkcg policy is active. This is really not worth bothering with. This patch makes blkcg always allocate and link the root blkcg_gq and release it only on queue destruction. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blkcg: move block/blk-cgroup.h to include/linux/blk-cgroup.hTejun Heo2015-06-027-609/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup aware writeback support will require exposing some of blkcg details. In preprataion, move block/blk-cgroup.h to include/linux/blk-cgroup.h. This patch is pure file move. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | | | Merge branch 'for-4.2/core' of git://git.kernel.dk/linux-blockLinus Torvalds2015-06-2515-255/+478
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull core block IO update from Jens Axboe: "Nothing really major in here, mostly a collection of smaller optimizations and cleanups, mixed with various fixes. In more detail, this contains: - Addition of policy specific data to blkcg for block cgroups. From Arianna Avanzini. - Various cleanups around command types from Christoph. - Cleanup of the suspend block I/O path from Christoph. - Plugging updates from Shaohua and Jeff Moyer, for blk-mq. - Eliminating atomic inc/dec of both remaining IO count and reference count in a bio. From me. - Fixes for SG gap and chunk size support for data-less (discards) IO, so we can merge these better. From me. - Small restructuring of blk-mq shared tag support, freeing drivers from iterating hardware queues. From Keith Busch. - A few cfq-iosched tweaks, from Tahsin Erdogan and me. Makes the IOPS mode the default for non-rotational storage" * 'for-4.2/core' of git://git.kernel.dk/linux-block: (35 commits) cfq-iosched: fix other locations where blkcg_to_cfqgd() can return NULL cfq-iosched: fix sysfs oops when attempting to read unconfigured weights cfq-iosched: move group scheduling functions under ifdef cfq-iosched: fix the setting of IOPS mode on SSDs blktrace: Add blktrace.c to BLOCK LAYER in MAINTAINERS file block, cgroup: implement policy-specific per-blkcg data block: Make CFQ default to IOPS mode on SSDs block: add blk_set_queue_dying() to blkdev.h blk-mq: Shared tag enhancements block: don't honor chunk sizes for data-less IO block: only honor SG gap prevention for merges that contain data block: fix returnvar.cocci warnings block, dm: don't copy bios for request clones block: remove management of bi_remaining when restoring original bi_end_io block: replace trylock with mutex_lock in blkdev_reread_part() block: export blkdev_reread_part() and __blkdev_reread_part() suspend: simplify block I/O handling block: collapse bio bit space block: remove unused BIO_RW_BLOCK and BIO_EOF flags block: remove BIO_EOPNOTSUPP ...
| * | | | cfq-iosched: fix other locations where blkcg_to_cfqgd() can return NULLJens Axboe2015-06-201-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 9470e4a693db only covered the initial bug report, there are other spots in CFQ where we need to check that we actually have a valid cfq_group_data structure. Fixes: e48453c3 ("block, cgroup: implement policy-specific per-blkcg data") Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | cfq-iosched: fix sysfs oops when attempting to read unconfigured weightsJens Axboe2015-06-191-2/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If none of the devices in the system are using CFQ, then attempting to read: /sys/fs/cgroup/blkio/blkio.leaf_weight will results in a NULL dereference. Check for a valid cfq_group_data struct before attempting to dereference it. Reported-by: Andrey Wagin <avagin@gmail.com> Fixes: e48453c3 ("block, cgroup: implement policy-specific per-blkcg data") Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | cfq-iosched: move group scheduling functions under ifdefJens Axboe2015-06-191-16/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If CFQ_GROUP_IOSCHED is not set, the compiler produces the following warning: CC block/cfq-iosched.o linux/block/cfq-iosched.c:469:2: warning: 'cpd_to_cfqgd' defined but not used [-Wunused-function] *cpd_to_cfqgd(struct blkcg_policy_data *cpd) ^ In reality, two other lookup functions aren't used either if CFQ_GROUP_IOSCHED isn't set. Move all three under one of the CFQ_GROUP_IOSCHED sections in the code. Reported-by: Vladimir Zapolskiy <vz@mleia.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | cfq-iosched: fix the setting of IOPS mode on SSDsJens Axboe2015-06-102-1/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A previous commit wanted to make CFQ default to IOPS mode on non-rotational storage, however it did so when the queue was initialized and the non-rotational flag is only set later on in the probe. Add an elevator hook that gets called off the add_disk() path, at that point we know that feature probing has finished, and we can reliably check for the various flags that drivers can set. Fixes: 41c0126b ("block: Make CFQ default to IOPS mode on SSDs") Tested-by: Romain Francoise <romain@orebokech.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | block, cgroup: implement policy-specific per-blkcg dataArianna Avanzini2015-06-073-29/+173
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The block IO (blkio) controller enables the block layer to provide service guarantees in a hierarchical fashion. Specifically, service guarantees are provided by registered request-accounting policies. As of now, a proportional-share and a throttling policy are available. They are implemented, respectively, by the CFQ I/O scheduler and the blk-throttle subsystem. Unfortunately, as for adding new policies, the current implementation of the block IO controller is only halfway ready to allow new policies to be plugged in. This commit provides a solution to make the block IO controller fully ready to handle new policies. In what follows, we first describe briefly the current state, and then list the changes made by this commit. The throttling policy does not need any per-cgroup information to perform its task. In contrast, the proportional share policy uses, for each cgroup, both the weight assigned by the user to the cgroup, and a set of dynamically- computed weights, one for each device. The first, user-defined weight is stored in the blkcg data structure: the block IO controller allocates a private blkcg data structure for each cgroup in the blkio cgroups hierarchy (regardless of which policy is active). In other words, the block IO controller internally mirrors the blkio cgroups with private blkcg data structures. On the other hand, for each cgroup and device, the corresponding dynamically- computed weight is maintained in the following, different way. For each device, the block IO controller keeps a private blkcg_gq structure for each cgroup in blkio. In other words, block IO also keeps one private mirror copy of the blkio cgroups hierarchy for each device, made of blkcg_gq structures. Each blkcg_gq structure keeps per-policy information in a generic array of dynamically-allocated 'dedicated' data structures, one for each registered policy (so currently the array contains two elements). To be inserted into the generic array, each dedicated data structure embeds a generic blkg_policy_data structure. Consider now the array contained in the blkcg_gq structure corresponding to a given pair of cgroup and device: one of the elements of the array contains the dedicated data structure for the proportional-share policy, and this dedicated data structure contains the dynamically-computed weight for that pair of cgroup and device. The generic strategy adopted for storing per-policy data in blkcg_gq structures is already capable of handling new policies, whereas the one adopted with blkcg structures is not, because per-policy data are hard-coded in the blkcg structures themselves (currently only data related to the proportional- share policy). This commit addresses the above issues through the following changes: . It generalizes blkcg structures so that per-policy data are stored in the same way as in blkcg_gq structures. Specifically, it lets also the blkcg structure store per-policy data in a generic array of dynamically-allocated dedicated data structures. We will refer to these data structures as blkcg dedicated data structures, to distinguish them from the dedicated data structures inserted in the generic arrays kept by blkcg_gq structures. To allow blkcg dedicated data structures to be inserted in the generic array inside a blkcg structure, this commit also introduces a new blkcg_policy_data structure, which is the equivalent of blkg_policy_data for blkcg dedicated data structures. . It adds to the blkcg_policy structure, i.e., to the descriptor of a policy, a cpd_size field and a cpd_init field, to be initialized by the policy with, respectively, the size of the blkcg dedicated data structures, and the address of a constructor function for blkcg dedicated data structures. . It moves the CFQ-specific fields embedded in the blkcg data structure (i.e., the fields related to the proportional-share policy), into a new blkcg dedicated data structure called cfq_group_data. Signed-off-by: Paolo Valente <paolo.valente@unimore.it> Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | block: Make CFQ default to IOPS mode on SSDsTahsin Erdogan2015-06-051-1/+1
| |/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CFQ idling causes reduced IOPS throughput on non-rotational disks. Since disk head seeking is not applicable to SSDs, it doesn't really help performance by anticipating future near-by IO requests. By turning off idling (and switching to IOPS mode), we allow other processes to dispatch IO requests down to the driver and so increase IO throughput. Following FIO benchmark results were taken on a cloud SSD offering with idling on and off: Idling iops avg-lat(ms) stddev bw ------------------------------------------------------ On 7054 90.107 38.697 28217KB/s Off 29255 21.836 11.730 117022KB/s fio --name=temp --size=100G --time_based --ioengine=libaio \ --randrepeat=0 --direct=1 --invalidate=1 --verify=0 \ --verify_fatal=0 --rw=randread --blocksize=4k --group_reporting=1 \ --filename=/dev/sdb --runtime=10 --iodepth=64 --numjobs=10 And the following is from a local SSD run: Idling iops avg-lat(ms) stddev bw ------------------------------------------------------ On 19320 33.043 14.068 77281KB/s Off 21626 29.465 12.662 86507KB/s fio --name=temp --size=5G --time_based --ioengine=libaio \ --randrepeat=0 --direct=1 --invalidate=1 --verify=0 \ --verify_fatal=0 --rw=randread --blocksize=4k --group_reporting=1 \ --filename=/fio_data --runtime=10 --iodepth=64 --numjobs=10 Reviewed-by: Nauman Rafique <nauman@google.com> Signed-off-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | blk-mq: Shared tag enhancementsKeith Busch2015-06-013-2/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Storage controllers may expose multiple block devices that share hardware resources managed by blk-mq. This patch enhances the shared tags so a low-level driver can access the shared resources not tied to the unshared h/w contexts. This way the LLD can dynamically add and delete disks and request queues without having to track all the request_queue hctx's to iterate outstanding tags. Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | block: only honor SG gap prevention for merges that contain dataJens Axboe2015-05-291-1/+2
| | |/ | |/| | | | | | | | | | | | | | | | | | | We can safely merge anything that wont generate an SG list entry, so if the bio is data-less (discard), don't look at potential SG gaps. Signed-off-by: Jens Axboe <axboe@fb.com>
| * | block, dm: don't copy bios for request clonesChristoph Hellwig2015-05-221-83/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently dm-multipath has to clone the bios for every request sent to the lower devices, which wastes cpu cycles and ties down memory. This patch instead adds a new REQ_CLONE flag that instructs req_bio_endio to not complete bios attached to a request, which we set on clone requests similar to bios in a flush sequence. With this change I/O errors on a path failure only get propagated to dm-multipath, which can then either resubmit the I/O or complete the bios on the original request. I've done some basic testing of this on a Linux target with ALUA support, and it survives path failures during I/O nicely. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | block: remove management of bi_remaining when restoring original bi_end_ioMike Snitzer2015-05-222-23/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for non-chains") regressed all existing callers that followed this pattern: 1) saving a bio's original bi_end_io 2) wiring up an intermediate bi_end_io 3) restoring the original bi_end_io from intermediate bi_end_io 4) calling bio_endio() to execute the restored original bi_end_io The regression was due to BIO_CHAIN only ever getting set if bio_inc_remaining() is called. For the above pattern it isn't set until step 3 above (step 2 would've needed to establish BIO_CHAIN). As such the first bio_endio(), in step 2 above, never decremented __bi_remaining before calling the intermediate bi_end_io -- leaving __bi_remaining with the value 1 instead of 0. When bio_inc_remaining() occurred during step 3 it brought it to a value of 2. When the second bio_endio() was called, in step 4 above, it should've called the original bi_end_io but it didn't because there was an extra reference that wasn't dropped (due to atomic operations being optimized away since BIO_CHAIN wasn't set upfront). Fix this issue by removing the __bi_remaining management complexity for all callers that use the above pattern -- bio_chain() is the only interface that _needs_ to be concerned with __bi_remaining. For the above pattern callers just expect the bi_end_io they set to get called! Remove bio_endio_nodec() and also remove all bio_inc_remaining() calls that aren't associated with the bio_chain() interface. Also, the bio_inc_remaining() interface has been moved local to bio.c. Fixes: c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for non-chains") Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | block: replace trylock with mutex_lock in blkdev_reread_part()Ming Lei2015-05-201-2/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The only possible problem of using mutex_lock() instead of trylock is about deadlock. If there aren't any locks held before calling blkdev_reread_part(), deadlock can't be caused by this conversion. If there are locks held before calling blkdev_reread_part(), and if these locks arn't required in open, close handler and I/O path, deadlock shouldn't be caused too. Both user space's ioctl(BLKRRPART) and md_setup_drive() from init/do_mounts_md.c belongs to the 1st case, so the conversion is safe for the two cases. For loop, the previous patches in this pathset has fixed the ABBA lock dependency, so the conversion is OK. For nbd, tx_lock is held when calling the function: - both open and release won't hold the lock - when blkdev_reread_part() is run, I/O thread has been stopped already, so tx_lock won't be acquired in I/O path at that time. - so the conversion won't cause deadlock for nbd For dasd, both dasd_open(), dasd_release() and request function don't acquire any mutex/semphone, so the conversion should be safe. Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Jarod Wilson <jarod@redhat.com> Acked-by: Jarod Wilson <jarod@redhat.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | block: export blkdev_reread_part() and __blkdev_reread_part()Jarod Wilson2015-05-201-3/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch exports blkdev_reread_part() for block drivers, also introduce __blkdev_reread_part(). For some drivers, such as loop, reread of partitions can be run from the release path, and bd_mutex may already be held prior to calling ioctl_by_bdev(bdev, BLKRRPART, 0), so introduce __blkdev_reread_part for use in such cases. CC: Christoph Hellwig <hch@lst.de> CC: Jens Axboe <axboe@kernel.dk> CC: Tejun Heo <tj@kernel.org> CC: Alexander Viro <viro@zeniv.linux.org.uk> CC: Markus Pargmann <mpa@pengutronix.de> CC: Stefan Weinhuber <wein@de.ibm.com> CC: Stefan Haberland <stefan.haberland@de.ibm.com> CC: Sebastian Ott <sebott@linux.vnet.ibm.com> CC: Fabian Frederick <fabf@skynet.be> CC: Ming Lei <ming.lei@canonical.com> CC: David Herrmann <dh.herrmann@gmail.com> CC: Andrew Morton <akpm@linux-foundation.org> CC: Peter Zijlstra <peterz@infradead.org> CC: nbd-general@lists.sourceforge.net CC: linux-s390@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jarod Wilson <jarod@redhat.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | block: remove unused BIO_RW_BLOCK and BIO_EOF flagsChristoph Hellwig2015-05-191-2/+0
| | | | | | | | | | | | | | | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | block: remove BIO_EOPNOTSUPPChristoph Hellwig2015-05-191-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since the big barrier rewrite/removal in 2007 we never fail FLUSH or FUA requests, which means we can remove the magic BIO_EOPNOTSUPP flag to help propagating those to the buffer_head layer. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | block: use an atomic_t for mq_freeze_depthChristoph Hellwig2015-05-191-14/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | lockdep gets unhappy about the not disabling irqs when using the queue_lock around it. Instead of trying to fix that up just switch to an atomic_t and get rid of the lock. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | blk-mq: make plug work for mutiple disks and queuesShaohua Li2015-05-083-9/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Last patch makes plug work for multiple queue case. However it only works for single disk case, because it assumes only one request in the plug list. If a task is accessing multiple disks, eg MD/DM, the assumption is wrong. Let blk_attempt_plug_merge() record request from the same queue. V2: use NULL parameter in !mq case. Fix a bug. Add comments in blk_attempt_plug_merge to make it less (hopefully) confusion. Cc: Jens Axboe <axboe@fb.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | blk-mq: do limited block plug for multiple queue caseShaohua Li2015-05-081-23/+59
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | plug is still helpful for workload with IO merge, but it can be harmful otherwise especially with multiple hardware queues, as there is (supposed) no lock contention in this case and plug can introduce latency. For multiple queues, we do limited plug, eg plug only if there is request merge. If a request doesn't have merge with following request, the requet will be dispatched immediately. V2: check blk_queue_nomerges() as suggested by Jeff. Cc: Jens Axboe <axboe@fb.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | blk-mq: avoid re-initialize request which is failed in direct dispatchShaohua Li2015-05-081-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we directly issue a request and it fails, we use blk_mq_merge_queue_io(). But we already assigned bio to a request in blk_mq_bio_to_request. blk_mq_merge_queue_io shouldn't run blk_mq_bio_to_request again. Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | blk-mq: fix plugging in blk_sq_make_requestJeff Moyer2015-05-081-22/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following appears in blk_sq_make_request: /* * If we have multiple hardware queues, just go directly to * one of those for sync IO. */ We clearly don't have multiple hardware queues, here! This comment was introduced with this commit 07068d5b8e (blk-mq: split make request handler for multi and single queue): We want slightly different behavior from them: - On single queue devices, we currently use the per-process plug for deferred IO and for merging. - On multi queue devices, we don't use the per-process plug, but we want to go straight to hardware for SYNC IO. The old code had this: use_plug = !is_flush_fua && ((q->nr_hw_queues == 1) || !is_sync); and that was converted to: use_plug = !is_flush_fua && !is_sync; which is not equivalent. For the single queue case, that second half of the && expression is always true. So, what I think was actually inteded follows (and this more closely matches what is done in blk_queue_bio). V2: delete the 'likely', which should not be a big deal Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | blk: clean up plugShaohua Li2015-05-081-12/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current code looks like inner plug gets flushed with a blk_finish_plug(). Actually it's a nop. All requests/callbacks are added to current->plug, while only outmost plug is assigned to current->plug. So inner plug always has empty request/callback list, which makes blk_flush_plug_list() a nop. This tries to make the code more clear. Signed-off-by: Shaohua Li <shli@fb.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | block: move PM request support to IDEChristoph Hellwig2015-05-053-12/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | This removes the request types and hacks from the block code and into the old IDE driver. There is a small amunt of code duplication due to this, but it's not too bad. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | bio: skip atomic inc/dec of ->bi_cnt for most use casesJens Axboe2015-05-051-7/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Struct bio has a reference count that controls when it can be freed. Most uses cases is allocating the bio, which then returns with a single reference to it, doing IO, and then dropping that single reference. We can remove this atomic_dec_and_test() in the completion path, if nobody else is holding a reference to the bio. If someone does call bio_get() on the bio, then we flag the bio as now having valid count and that we must properly honor the reference count when it's being put. Tested-by: Robert Elliott <elliott@hp.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | bio: skip atomic inc/dec of ->bi_remaining for non-chainsJens Axboe2015-05-051-9/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Struct bio has an atomic ref count for chained bio's, and we use this to know when to end IO on the bio. However, most bio's are not chained, so we don't need to always introduce this atomic operation as part of ending IO. Add a helper to elevate the bi_remaining count, and flag the bio as now actually needing the decrement at end_io time. Rename the field to __bi_remaining to catch any current users of this doing the incrementing manually. For high IOPS workloads, this reduces the overhead of bio_endio() substantially. Tested-by: Robert Elliott <elliott@hp.com> Acked-by: Kent Overstreet <kent.overstreet@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
* | | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2015-06-221-1/+1
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "The main changes are: - lockless wakeup support for futexes and IPC message queues (Davidlohr Bueso, Peter Zijlstra) - Replace spinlocks with atomics in thread_group_cputimer(), to improve scalability (Jason Low) - NUMA balancing improvements (Rik van Riel) - SCHED_DEADLINE improvements (Wanpeng Li) - clean up and reorganize preemption helpers (Frederic Weisbecker) - decouple page fault disabling machinery from the preemption counter, to improve debuggability and robustness (David Hildenbrand) - SCHED_DEADLINE documentation updates (Luca Abeni) - topology CPU masks cleanups (Bartosz Golaszewski) - /proc/sched_debug improvements (Srikar Dronamraju)" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (79 commits) sched/deadline: Remove needless parameter in dl_runtime_exceeded() sched: Remove superfluous resetting of the p->dl_throttled flag sched/deadline: Drop duplicate init_sched_dl_class() declaration sched/deadline: Reduce rq lock contention by eliminating locking of non-feasible target sched/deadline: Make init_sched_dl_class() __init sched/deadline: Optimize pull_dl_task() sched/preempt: Add static_key() to preempt_notifiers sched/preempt: Fix preempt notifiers documentation about hlist_del() within unsafe iteration sched/stop_machine: Fix deadlock between multiple stop_two_cpus() sched/debug: Add sum_sleep_runtime to /proc/<pid>/sched sched/debug: Replace vruntime with wait_sum in /proc/sched_debug sched/debug: Properly format runnable tasks in /proc/sched_debug sched/numa: Only consider less busy nodes as numa balancing destinations Revert 095bebf61a46 ("sched/numa: Do not move past the balance point if unbalanced") sched/fair: Prevent throttling in early pick_next_task_fair() preempt: Reorganize the notrace definitions a bit preempt: Use preempt_schedule_context() as the official tracing preemption point sched: Make preempt_schedule_context() function-tracing safe x86: Remove cpu_sibling_mask() and cpu_core_mask() x86: Replace cpu_**_mask() with topology_**_cpumask() ...
| * \ \ Merge branch 'linus' into sched/core, to resolve conflictIngo Molnar2015-06-021-2/+3
| |\ \ \ | | | |/ | | |/| | | | | | | | | | | | | | | | | Conflicts: arch/sparc/include/asm/topology_64.h Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | sched/topology: Rename topology_thread_cpumask() to topology_sibling_cpumask()Bartosz Golaszewski2015-05-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rename topology_thread_cpumask() to topology_sibling_cpumask() for more consistency with scheduler code. Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Benoit Cousson <bcousson@baylibre.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jean Delvare <jdelvare@suse.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Drokin <oleg.drokin@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: http://lkml.kernel.org/r/1432645896-12588-2-git-send-email-bgolaszewski@baylibre.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | block: fix ext_dev_lock lockdep reportDan Williams2015-06-111-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ================================= [ INFO: inconsistent lock state ] 4.1.0-rc7+ #217 Tainted: G O --------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. swapper/6/0 [HC0[0]:SC1[1]:HE1:SE0] takes: (ext_devt_lock){+.?...}, at: [<ffffffff8143a60c>] blk_free_devt+0x3c/0x70 {SOFTIRQ-ON-W} state was registered at: [<ffffffff810bf6b1>] __lock_acquire+0x461/0x1e70 [<ffffffff810c1947>] lock_acquire+0xb7/0x290 [<ffffffff818ac3a8>] _raw_spin_lock+0x38/0x50 [<ffffffff8143a07d>] blk_alloc_devt+0x6d/0xd0 <-- take the lock in process context [..] [<ffffffff810bf64e>] __lock_acquire+0x3fe/0x1e70 [<ffffffff810c00ad>] ? __lock_acquire+0xe5d/0x1e70 [<ffffffff810c1947>] lock_acquire+0xb7/0x290 [<ffffffff8143a60c>] ? blk_free_devt+0x3c/0x70 [<ffffffff818ac3a8>] _raw_spin_lock+0x38/0x50 [<ffffffff8143a60c>] ? blk_free_devt+0x3c/0x70 [<ffffffff8143a60c>] blk_free_devt+0x3c/0x70 <-- take the lock in softirq [<ffffffff8143bfec>] part_release+0x1c/0x50 [<ffffffff8158edf6>] device_release+0x36/0xb0 [<ffffffff8145ac2b>] kobject_cleanup+0x7b/0x1a0 [<ffffffff8145aad0>] kobject_put+0x30/0x70 [<ffffffff8158f147>] put_device+0x17/0x20 [<ffffffff8143c29c>] delete_partition_rcu_cb+0x16c/0x180 [<ffffffff8143c130>] ? read_dev_sector+0xa0/0xa0 [<ffffffff810e0e0f>] rcu_process_callbacks+0x2ff/0xa90 [<ffffffff810e0dcf>] ? rcu_process_callbacks+0x2bf/0xa90 [<ffffffff81067e2e>] __do_softirq+0xde/0x600 Neil sees this in his tests and it also triggers on pmem driver unbind for the libnvdimm tests. This fix is on top of an initial fix by Keith for incorrect usage of mutex_lock() in this path: 2da78092dda1 "block: Fix dev_t minor allocation lifetime". Both this and 2da78092dda1 are candidates for -stable. Fixes: 2da78092dda1 ("block: Fix dev_t minor allocation lifetime") Cc: <stable@vger.kernel.org> Cc: Keith Busch <keith.busch@intel.com> Reported-by: NeilBrown <neilb@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | | | blk-mq: free hctx->ctxs in queue's release handlerMing Lei2015-06-091-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now blk_cleanup_queue() can be called before calling del_gendisk()[1], inside which hctx->ctxs is touched from blk_mq_unregister_hctx(), but the variable has been freed by blk_cleanup_queue() at that time. So this patch moves freeing of hctx->ctxs into queue's release handler for fixing the oops reported by Stefan. [1], 6cd18e711dd8075 (block: destroy bdi before blockdev is unregistered) Reported-by: Stefan Seyfried <stefan.seyfried@googlemail.com> Cc: NeilBrown <neilb@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org (v4.0) Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | | | block: discard bdi_unregister() in favour of bdi_destroy()NeilBrown2015-05-281-1/+0
| |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bdi_unregister() now contains very little functionality. It contains a "WARN_ON" if bdi->dev is NULL. This warning is of no real consequence as bdi->dev isn't needed by anything else in the function, and it triggers if blk_cleanup_queue() -> bdi_destroy() is called before bdi_unregister, which happens since Commit: 6cd18e711dd8 ("block: destroy bdi before blockdev is unregistered.") So this isn't wanted. It also calls bdi_set_min_ratio(). This needs to be called after writes through the bdi have all been flushed, and before the bdi is destroyed. Calling it early is better than calling it late as it frees up a global resource. Calling it immediately after bdi_wb_shutdown() in bdi_destroy() perfectly fits these requirements. So bdi_unregister() can be discarded with the important content moved to bdi_destroy(), as can the writeback_bdi_unregister event which is already not used. Reported-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org (v4.0) Fixes: c4db59d31e39 ("fs: don't reassign dirty inodes to default_backing_dev_info") Fixes: 6cd18e711dd8 ("block: destroy bdi before blockdev is unregistered.") Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Nicholas Moulin <nicholas.w.moulin@linux.intel.com> Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* | | block: remove export for blk_queue_bioMike Snitzer2015-05-121-2/+3
|/ / | | | | | | | | | | | | | | | | | | With commit ff36ab345 ("dm: remove request-based logic from make_request_fn wrapper") DM no longer calls blk_queue_bio() directly, so remove its export. Doing so required a forward declaration in blk-core.c. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | blk-mq: don't lose requests if a stopped queue restartsShaohua Li2015-05-041-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Normally if driver is busy to dispatch a request the logic is like below: block layer: driver: __blk_mq_run_hw_queue a. blk_mq_stop_hw_queue b. rq add to ctx->dispatch later: 1. blk_mq_start_hw_queue 2. __blk_mq_run_hw_queue But it's possible step 1-2 runs between a and b. And since rq isn't in ctx->dispatch yet, step 2 will not run rq. The rq might get lost if there are no subsequent requests kick in. Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | block: destroy bdi before blockdev is unregistered.NeilBrown2015-04-272-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Because of the peculiar way that md devices are created (automatically when the device node is opened), a new device can be created and registered immediately after the blk_unregister_region(disk_devt(disk), disk->minors); call in del_gendisk(). Therefore it is important that all visible artifacts of the previous device are removed before this call. In particular, the 'bdi'. Since: commit c4db59d31e39ea067c32163ac961e9c80198fd37 Author: Christoph Hellwig <hch@lst.de> fs: don't reassign dirty inodes to default_backing_dev_info moved the device_unregister(bdi->dev); call from bdi_unregister() to bdi_destroy() it has been quite easy to lose a race and have a new (e.g.) "md127" be created after the blk_unregister_region() call and before bdi_destroy() is ultimately called by the final 'put_disk', which must come after del_gendisk(). The new device finds that the bdi name is already registered in sysfs and complains > [ 9627.630029] WARNING: CPU: 18 PID: 3330 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x5a/0x70() > [ 9627.630032] sysfs: cannot create duplicate filename '/devices/virtual/bdi/9:127' We can fix this by moving the bdi_destroy() call out of blk_release_queue() (which can happen very late when a refcount reaches zero) and into blk_cleanup_queue() - which happens exactly when the md device driver calls it. Then it is only necessary for md to call blk_cleanup_queue() before del_gendisk(). As loop.c devices are also created on demand by opening the device node, we make the same change there. Fixes: c4db59d31e39ea067c32163ac961e9c80198fd37 Reported-by: Azat Khuzhin <a3at.mail@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org (v4.0) Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>