linux/mm/backing-dev.c, branch v3.18

Merge branch 'for-3.18/core' of git://git.kernel.dk/linux-block

2014-10-18T18:53:51Z

Pull core block layer changes from Jens Axboe: "This is the core block IO pull request for 3.18. Apart from the new and improved flush machinery for blk-mq, this is all mostly bug fixes and cleanups. - blk-mq timeout updates and fixes from Christoph. - Removal of REQ_END, also from Christoph. We pass it through the ->queue_rq() hook for blk-mq instead, freeing up one of the request bits. The space was overly tight on 32-bit, so Martin also killed REQ_KERNEL since it's no longer used. - blk integrity updates and fixes from Martin and Gu Zheng. - Update to the flush machinery for blk-mq from Ming Lei. Now we have a per hardware context flush request, which both cleans up the code should scale better for flush intensive workloads on blk-mq. - Improve the error printing, from Rob Elliott. - Backing device improvements and cleanups from Tejun. - Fixup of a misplaced rq_complete() tracepoint from Hannes. - Make blk_get_request() return error pointers, fixing up issues where we NULL deref when a device goes bad or missing. From Joe Lawrence. - Prep work for drastically reducing the memory consumption of dm devices from Junichi Nomura. This allows creating clone bio sets without preallocating a lot of memory. - Fix a blk-mq hang on certain combinations of queue depths and hardware queues from me. - Limit memory consumption for blk-mq devices for crash dump scenarios and drivers that use crazy high depths (certain SCSI shared tag setups). We now just use a single queue and limited depth for that" * 'for-3.18/core' of git://git.kernel.dk/linux-block: (58 commits) block: Remove REQ_KERNEL blk-mq: allocate cpumask on the home node bio-integrity: remove the needless fail handle of bip_slab creating block: include func name in __get_request prints block: make blk_update_request print prefix match ratelimited prefix blk-merge: don't compute bi_phys_segments from bi_vcnt for cloned bio block: fix alignment_offset math that assumes io_min is a power-of-2 blk-mq: Make bt_clear_tag() easier to read blk-mq: fix potential hang if rolling wakeup depth is too high block: add bioset_create_nobvec() block: use bio_clone_fast() in blk_rq_prep_clone() block: misplaced rq_complete tracepoint sd: Honor block layer integrity handling flags block: Replace strnicmp with strncasecmp block: Add T10 Protection Information functions block: Don't merge requests if integrity flags differ block: Integrity checksum flag block: Relocate bio integrity flags block: Add a disk flag to block integrity profile block: Add prefix to block integrity profile flags ...

Merge branch 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2014-10-10T11:26:02Z

Pull percpu updates from Tejun Heo: "A lot of activities on percpu front. Notable changes are... - percpu allocator now can take @gfp. If @gfp doesn't contain GFP_KERNEL, it tries to allocate from what's already available to the allocator and a work item tries to keep the reserve around certain level so that these atomic allocations usually succeed. This will replace the ad-hoc percpu memory pool used by blk-throttle and also be used by the planned blkcg support for writeback IOs. Please note that I noticed a bug in how @gfp is interpreted while preparing this pull request and applied the fix 6ae833c7fe0c ("percpu: fix how @gfp is interpreted by the percpu allocator") just now. - percpu_ref now uses longs for percpu and global counters instead of ints. It leads to more sparse packing of the percpu counters on 64bit machines but the overhead should be negligible and this allows using percpu_ref for refcnting pages and in-memory objects directly. - The switching between percpu and single counter modes of a percpu_ref is made independent of putting the base ref and a percpu_ref can now optionally be initialized in single or killed mode. This allows avoiding percpu shutdown latency for cases where the refcounted objects may be synchronously created and destroyed in rapid succession with only a fraction of them reaching fully operational status (SCSI probing does this when combined with blk-mq support). It's also planned to be used to implement forced single mode to detect underflow more timely for debugging. There's a separate branch percpu/for-3.18-consistent-ops which cleans up the duplicate percpu accessors. That branch causes a number of conflicts with s390 and other trees. I'll send a separate pull request w/ resolutions once other branches are merged" * 'for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (33 commits) percpu: fix how @gfp is interpreted by the percpu allocator blk-mq, percpu_ref: start q->mq_usage_counter in atomic mode percpu_ref: make INIT_ATOMIC and switch_to_atomic() sticky percpu_ref: add PERCPU_REF_INIT_* flags percpu_ref: decouple switching to percpu mode and reinit percpu_ref: decouple switching to atomic mode and killing percpu_ref: add PCPU_REF_DEAD percpu_ref: rename things to prepare for decoupling percpu/atomic mode switch percpu_ref: replace pcpu_ prefix with percpu_ percpu_ref: minor code and comment updates percpu_ref: relocate percpu_ref_reinit() Revert "blk-mq, percpu_ref: implement a kludge for SCSI blk-mq stall during probe" Revert "percpu: free percpu allocation info for uniprocessor system" percpu-refcount: make percpu_ref based on longs instead of ints percpu-refcount: improve WARN messages percpu: fix locking regression in the failure path of pcpu_alloc() percpu-refcount: add @gfp to percpu_ref_init() proportions: add @gfp to init functions percpu_counter: add @gfp to percpu_counter_init() percpu_counter: make percpu_counters_lock irq-safe ...

mm: clean up zone flags

2014-10-10T02:25:57Z

Page reclaim tests zone_is_reclaim_dirty(), but the site that actually sets this state does zone_set_flag(zone, ZONE_TAIL_LRU_DIRTY), sending the reader through layers indirection just to track down a simple bit. Remove all zone flag wrappers and just use bitops against zone->flags directly. It's just as readable and the lines are barely any longer. Also rename ZONE_TAIL_LRU_DIRTY to ZONE_DIRTY to match ZONE_WRITEBACK, and remove the zone_flags_t typedef. Signed-off-by: Johannes Weiner Acked-by: David Rientjes Acked-by: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

bdi: reimplement bdev_inode_switch_bdi()

2014-09-08T16:00:43Z

A block_device may be attached to different gendisks and thus different bdis over time. bdev_inode_switch_bdi() is used to switch the associated bdi. The function assumes that the inode could be dirty and transfers it between bdis if so. This is a bit nasty in that it reaches into bdi internals. This patch reimplements the function so that it writes out the inode if dirty. This is a lot simpler and can be implemented without exposing bdi internals. Signed-off-by: Tejun Heo Cc: Alexander Viro Signed-off-by: Jens Axboe

bdi: explain the dirty list transferring in bdi_destroy()

2014-09-08T16:00:41Z

bdi_destroy() has code to transfer the remaining dirty inodes to the default_backing_dev_info; however, given the shutdown sequence, it isn't clear how such condition would happen. Also, it isn't a full solution as the transferred inodes stlil point to the bdi which is being destroyed. Operations on those inodes can end up accessing already released fields such as the percpu stat fields. Digging through the history, it seems that the code was added as a quick workaround for a bug report without fully root-causing the issue. We probably want to remove the code in time but for now let's add a comment noting that it is a quick workaround. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe

bdi: make backing_dev_info->wb.dwork canceling stricter

2014-09-08T16:00:39Z

Canceling of bdi->wb.dwork is currently a bit mushy. bdi_wb_shutdown() performs cancel_delayed_work_sync() at the end after shutting down and flushing the delayed_work and bdi_destroy() tries yet again after bdi_unregister(). bdi->wb.dwork is queued only after checking BDI_registered while holding bdi->wb_lock and bdi_wb_shutdown() clears the flag while holding the same lock and then flushes the delayed_work. There's no way the delayed_work can be queued again after that. Replace the two unnecessary cancel_delayed_work_sync() invocations with WARNs on pending. This simplifies and clarifies the code a bit and will help future changes in further isolating bdi_writeback handling. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe

bdi: remove bdi->wb_lock locking around bdi->dev clearing in bdi_unregister()

2014-09-08T16:00:38Z

The only places where NULL test on bdi->dev is used are bdi_[un]register(). The functions can't be called in parallel anyway and there's no point in protecting bdi->dev clearing with a lock. Remove bdi->wb_lock grabbing around bdi->dev clearing and move it after device_unregister() call so that bdi->dev doesn't have to be cached in a local variable. This patch shouldn't introduce any behavior difference. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe

proportions: add @gfp to init functions

2014-09-08T00:51:30Z

Percpu allocator now supports allocation mask. Add @gfp to [flex_]proportions init functions so that !GFP_KERNEL allocation masks can be used with them too. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo Reviewed-by: Jan Kara Cc: Peter Zijlstra

percpu_counter: add @gfp to percpu_counter_init()

2014-09-08T00:51:29Z

Percpu allocator now supports allocation mask. Add @gfp to percpu_counter_init() so that !GFP_KERNEL allocation masks can be used with percpu_counters too. We could have left percpu_counter_init() alone and added percpu_counter_init_gfp(); however, the number of users isn't that high and introducing _gfp variants to all percpu data structures would be quite ugly, so let's just do the conversion. This is the one with the most users. Other percpu data structures are a lot easier to convert. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo Acked-by: Jan Kara Acked-by: "David S. Miller" Cc: x86@kernel.org Cc: Jens Axboe Cc: "Theodore Ts'o" Cc: Alexander Viro Cc: Andrew Morton

arch: Mass conversion of smp_mb__*()

2014-04-18T12:20:48Z

Mostly scripted conversion of the smp_mb__* barriers. Signed-off-by: Peter Zijlstra Acked-by: Paul E. McKenney Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org Cc: Linus Torvalds Cc: linux-arch@vger.kernel.org Signed-off-by: Ingo Molnar