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This commit adds consistency to examples, formatting, and a couple of
additional warnings.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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This commit adds design documentation for expedited grace periods.
This documentation is in HTML rather than the new documentation
format because (1) I have prototype documentation already in HTML,
and (2) Attempting to learn the new documentation format while
creating the design documentation seems likely to result in neither
happening in a timely fashion.
Once the design documentation is complete, we can start a conversion effort.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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The current preemptible RCU implementation goes through three phases
during bootup. In the first phase, there is only one CPU that is running
with preemption disabled, so that a no-op is a synchronous grace period.
In the second mid-boot phase, the scheduler is running, but RCU has
not yet gotten its kthreads spawned (and, for expedited grace periods,
workqueues are not yet running. During this time, any attempt to do
a synchronous grace period will hang the system (or complain bitterly,
depending). In the third and final phase, RCU is fully operational and
everything works normally.
This has been OK for some time, but there has recently been some
synchronous grace periods showing up during the second mid-boot phase.
This code worked "by accident" for awhile, but started failing as soon
as expedited RCU grace periods switched over to workqueues in commit
8b355e3bc140 ("rcu: Drive expedited grace periods from workqueue").
Note that the code was buggy even before this commit, as it was subject
to failure on real-time systems that forced all expedited grace periods
to run as normal grace periods (for example, using the rcu_normal ksysfs
parameter). The callchain from the failure case is as follows:
early_amd_iommu_init()
|-> acpi_put_table(ivrs_base);
|-> acpi_tb_put_table(table_desc);
|-> acpi_tb_invalidate_table(table_desc);
|-> acpi_tb_release_table(...)
|-> acpi_os_unmap_memory
|-> acpi_os_unmap_iomem
|-> acpi_os_map_cleanup
|-> synchronize_rcu_expedited
The kernel showing this callchain was built with CONFIG_PREEMPT_RCU=y,
which caused the code to try using workqueues before they were
initialized, which did not go well.
This commit therefore reworks RCU to permit synchronous grace periods
to proceed during this mid-boot phase. This commit is therefore a
fix to a regression introduced in v4.9, and is therefore being put
forward post-merge-window in v4.10.
This commit sets a flag from the existing rcu_scheduler_starting()
function which causes all synchronous grace periods to take the expedited
path. The expedited path now checks this flag, using the requesting task
to drive the expedited grace period forward during the mid-boot phase.
Finally, this flag is updated by a core_initcall() function named
rcu_exp_runtime_mode(), which causes the runtime codepaths to be used.
Note that this arrangement assumes that tasks are not sent POSIX signals
(or anything similar) from the time that the first task is spawned
through core_initcall() time.
Fixes: 8b355e3bc140 ("rcu: Drive expedited grace periods from workqueue")
Reported-by: "Zheng, Lv" <lv.zheng@intel.com>
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Stan Kain <stan.kain@gmail.com>
Tested-by: Ivan <waffolz@hotmail.com>
Tested-by: Emanuel Castelo <emanuel.castelo@gmail.com>
Tested-by: Bruno Pesavento <bpesavento@infinito.it>
Tested-by: Borislav Petkov <bp@suse.de>
Tested-by: Frederic Bezies <fredbezies@gmail.com>
Cc: <stable@vger.kernel.org> # 4.9.0-
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It is now legal to invoke synchronize_sched() at early boot, which causes
Tiny RCU's synchronize_sched() to emit spurious splats. This commit
therefore removes the cond_resched() from Tiny RCU's synchronize_sched().
Fixes: 8b355e3bc140 ("rcu: Drive expedited grace periods from workqueue")
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> # 4.9.0-
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro.
The most notable fix here is probably the fix for a splice regression
("fix a fencepost error in pipe_advance()") noticed by Alan Wylie.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fix a fencepost error in pipe_advance()
coredump: Ensure proper size of sparse core files
aio: fix lock dep warning
tmpfs: clear S_ISGID when setting posix ACLs
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Pull block fixes from Jens Axboe:
- the virtio_blk stack DMA corruption fix from Christoph, fixing and
issue with VMAP stacks.
- O_DIRECT blkbits calculation fix from Chandan.
- discard regression fix from Christoph.
- queue init error handling fixes for nbd and virtio_blk, from Omar and
Jeff.
- two small nvme fixes, from Christoph and Guilherme.
- rename of blk_queue_zone_size and bdev_zone_size to _sectors instead,
to more closely follow what we do in other places in the block layer.
This interface is new for this series, so let's get the naming right
before releasing a kernel with this feature. From Damien.
* 'for-linus' of git://git.kernel.dk/linux-block:
block: don't try to discard from __blkdev_issue_zeroout
sd: remove __data_len hack for WRITE SAME
nvme: use blk_rq_payload_bytes
scsi: use blk_rq_payload_bytes
block: add blk_rq_payload_bytes
block: Rename blk_queue_zone_size and bdev_zone_size
nvme: apply DELAY_BEFORE_CHK_RDY quirk at probe time too
nvme-rdma: fix nvme_rdma_queue_is_ready
virtio_blk: fix panic in initialization error path
nbd: blk_mq_init_queue returns an error code on failure, not NULL
virtio_blk: avoid DMA to stack for the sense buffer
do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned
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The logics in pipe_advance() used to release all buffers past the new
position failed in cases when the number of buffers to release was equal
to pipe->buffers. If that happened, none of them had been released,
leaving pipe full. Worse, it was trivial to trigger and we end up with
pipe full of uninitialized pages. IOW, it's an infoleak.
Cc: stable@vger.kernel.org # v4.9
Reported-by: "Alan J. Wylie" <alan@wylie.me.uk>
Tested-by: "Alan J. Wylie" <alan@wylie.me.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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If the last section of a core file ends with an unmapped or zero page,
the size of the file does not correspond with the last dump_skip() call.
gdb complains that the file is truncated and can be confusing to users.
After all of the vma sections are written, make sure that the file size
is no smaller than the current file position.
This problem can be demonstrated with gdb's bigcore testcase on the
sparc architecture.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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lockdep reports a warnning. file_start_write/file_end_write only
acquire/release the lock for regular files. So checking the files in aio
side too.
[ 453.532141] ------------[ cut here ]------------
[ 453.533011] WARNING: CPU: 1 PID: 1298 at ../kernel/locking/lockdep.c:3514 lock_release+0x434/0x670
[ 453.533011] DEBUG_LOCKS_WARN_ON(depth <= 0)
[ 453.533011] Modules linked in:
[ 453.533011] CPU: 1 PID: 1298 Comm: fio Not tainted 4.9.0+ #964
[ 453.533011] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.0-1.fc24 04/01/2014
[ 453.533011] ffff8803a24b7a70 ffffffff8196cffb ffff8803a24b7ae8 0000000000000000
[ 453.533011] ffff8803a24b7ab8 ffffffff81091ee1 ffff8803a5dba700 00000dba00000008
[ 453.533011] ffffed0074496f59 ffff8803a5dbaf54 ffff8803ae0f8488 fffffffffffffdef
[ 453.533011] Call Trace:
[ 453.533011] [<ffffffff8196cffb>] dump_stack+0x67/0x9c
[ 453.533011] [<ffffffff81091ee1>] __warn+0x111/0x130
[ 453.533011] [<ffffffff81091f97>] warn_slowpath_fmt+0x97/0xb0
[ 453.533011] [<ffffffff81091f00>] ? __warn+0x130/0x130
[ 453.533011] [<ffffffff8191b789>] ? blk_finish_plug+0x29/0x60
[ 453.533011] [<ffffffff811205d4>] lock_release+0x434/0x670
[ 453.533011] [<ffffffff8198af94>] ? import_single_range+0xd4/0x110
[ 453.533011] [<ffffffff81322195>] ? rw_verify_area+0x65/0x140
[ 453.533011] [<ffffffff813aa696>] ? aio_write+0x1f6/0x280
[ 453.533011] [<ffffffff813aa6c9>] aio_write+0x229/0x280
[ 453.533011] [<ffffffff813aa4a0>] ? aio_complete+0x640/0x640
[ 453.533011] [<ffffffff8111df20>] ? debug_check_no_locks_freed+0x1a0/0x1a0
[ 453.533011] [<ffffffff8114793a>] ? debug_lockdep_rcu_enabled.part.2+0x1a/0x30
[ 453.533011] [<ffffffff81147985>] ? debug_lockdep_rcu_enabled+0x35/0x40
[ 453.533011] [<ffffffff812a92be>] ? __might_fault+0x7e/0xf0
[ 453.533011] [<ffffffff813ac9bc>] do_io_submit+0x94c/0xb10
[ 453.533011] [<ffffffff813ac2ae>] ? do_io_submit+0x23e/0xb10
[ 453.533011] [<ffffffff813ac070>] ? SyS_io_destroy+0x270/0x270
[ 453.533011] [<ffffffff8111d7b3>] ? mark_held_locks+0x23/0xc0
[ 453.533011] [<ffffffff8100201a>] ? trace_hardirqs_on_thunk+0x1a/0x1c
[ 453.533011] [<ffffffff813acb90>] SyS_io_submit+0x10/0x20
[ 453.533011] [<ffffffff824f96aa>] entry_SYSCALL_64_fastpath+0x18/0xad
[ 453.533011] [<ffffffff81119190>] ? trace_hardirqs_off_caller+0xc0/0x110
[ 453.533011] ---[ end trace b2fbe664d1cc0082 ]---
Cc: Dmitry Monakhov <dmonakhov@openvz.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Reviewed-by: Jeff Layton <jlayton@redhat.com>
CC: Stable <stable@vger.kernel.org>
file_info_lock is not initalized in initiate_cifs_search(), leading to the
following splat after a simple "mount.cifs ... dir && ls dir/":
BUG: spinlock bad magic on CPU#0, ls/486
lock: 0xffff880009301110, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
CPU: 0 PID: 486 Comm: ls Not tainted 4.9.0 #27
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
ffffc900042f3db0 ffffffff81327533 0000000000000000 ffff880009301110
ffffc900042f3dd0 ffffffff810baf75 ffff880009301110 ffffffff817ae077
ffffc900042f3df0 ffffffff810baff6 ffff880009301110 ffff880008d69900
Call Trace:
[<ffffffff81327533>] dump_stack+0x65/0x92
[<ffffffff810baf75>] spin_dump+0x85/0xe0
[<ffffffff810baff6>] spin_bug+0x26/0x30
[<ffffffff810bb159>] do_raw_spin_lock+0xe9/0x130
[<ffffffff8159ad2f>] _raw_spin_lock+0x1f/0x30
[<ffffffff8127e50d>] cifs_closedir+0x4d/0x100
[<ffffffff81181cfd>] __fput+0x5d/0x160
[<ffffffff81181e3e>] ____fput+0xe/0x10
[<ffffffff8109410e>] task_work_run+0x7e/0xa0
[<ffffffff81002512>] exit_to_usermode_loop+0x92/0xa0
[<ffffffff810026f9>] syscall_return_slowpath+0x49/0x50
[<ffffffff8159b484>] entry_SYSCALL_64_fastpath+0xa7/0xa9
Fixes: 3afca265b5f53a0 ("Clarify locking of cifs file and tcon structures and make more granular")
Signed-off-by: Rabin Vincent <rabinv@axis.com>
Signed-off-by: Steve French <smfrench@gmail.com>
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git://git.infradead.org/users/vkoul/slave-dma
Pull dmaengine fixes from Vinod Koul:
"The fixes this time around are spread over drivers, pretty normal
update:
- PCI ID for SKL ioatdma, workaround for SKX and
ioat_alloc_chan_resources sleepy allocation fix
- dw kconfig typo fix
- null pointer deref for stm32
- MAINTAINERS Update for at_hdmac
- pl330 runtime pm fixes
- omap-dma port window fix
- rcar-dmac unmap slave resource fix"
* tag 'dmaengine-fix-4.10-rc4' of git://git.infradead.org/users/vkoul/slave-dma:
dmaengine: rcar-dmac: unmap slave resource when channel is freed
dmaengine: omap-dma: Fix the port_window support
dmaengine: iota: ioat_alloc_chan_resources should not perform sleeping allocations.
dmaengine: pl330: Fix runtime PM support for terminated transfers
MAINTAINERS: dmaengine: Update + Hand over the at_hdmac driver to Ludovic
dmaengine: omap-dma: Fix dynamic lch_map allocation
dmaengine: ti-dma-crossbar: Add some 'of_node_put()' in error path.
dmaengine: stm32-dma: Fix null pointer dereference in stm32_dma_tx_status
dmaengine: stm32-dma: Set correct args number for DMA request from DT
dmaengine: dw: fix typo in Kconfig
dmaengine: ioatdma: workaround SKX ioatdma version
dmaengine: ioatdma: Add Skylake PCI Dev ID
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Mike noticed this bogosity:
> > +# define mutex_lock_nest_io(lock, nest_lock) mutex_io(lock)
> ^^^^^^^^^^^^^^ typo
This new locking API is not used yet, so this didn't trigger in testing.
Fix it.
Reported-by: Mike Galbraith <efault@gmx.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: adilger.kernel@dilger.ca
Cc: jack@suse.com
Cc: kernel-team@fb.com
Cc: mingbo@fb.com
Cc: tytso@mit.edu
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Some machines, such as the Lenovo ThinkPad W541 with firmware GNET80WW
(2.28), include memory map entries with phys_addr=0x0 and num_pages=0.
These machines fail to boot after the following commit,
commit 8e80632fb23f ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()")
Fix this by removing such bogus entries from the memory map.
Furthermore, currently the log output for this case (with efi=debug)
looks like:
[ 0.000000] efi: mem45: [Reserved | | | | | | | | | | | | ] range=[0x0000000000000000-0xffffffffffffffff] (0MB)
This is clearly wrong, and also not as informative as it could be. This
patch changes it so that if we find obviously invalid memory map
entries, we print an error and skip those entries. It also detects the
display of the address range calculation overflow, so the new output is:
[ 0.000000] efi: [Firmware Bug]: Invalid EFI memory map entries:
[ 0.000000] efi: mem45: [Reserved | | | | | | | | | | | | ] range=[0x0000000000000000-0x0000000000000000] (invalid)
It also detects memory map sizes that would overflow the physical
address, for example phys_addr=0xfffffffffffff000 and
num_pages=0x0200000000000001, and prints:
[ 0.000000] efi: [Firmware Bug]: Invalid EFI memory map entries:
[ 0.000000] efi: mem45: [Reserved | | | | | | | | | | | | ] range=[phys_addr=0xfffffffffffff000-0x20ffffffffffffffff] (invalid)
It then removes these entries from the memory map.
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[ardb: refactor for clarity with no functional changes, avoid PAGE_SHIFT]
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
[Matt: Include bugzilla info in commit log]
Cc: <stable@vger.kernel.org> # v4.9+
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=191121
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This reverts commit 6751667a29d6fd64afb9ce30567ad616b68ed789.
Rob Herring objected to it, and a replacement for it will be added using
debugfs in the future.
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Reported-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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With the ww_mutex inline wrappers gone there's a lot of dormant
anti-patterns emerging in an x86 allyesconfig build:
kernel/locking/test-ww_mutex.c:80:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
kernel/locking/test-ww_mutex.c:55:3: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
kernel/locking/test-ww_mutex.c:134:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
kernel/locking/test-ww_mutex.c:213:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
kernel/locking/test-ww_mutex.c:177:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
kernel/locking/test-ww_mutex.c:266:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:213:19: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
lib/locking-selftest.c:211:20: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/drm_modeset_lock.c:430:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c:70:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/vgem/vgem_fence.c:193:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/i915/i915_gem_batch_pool.c:125:4: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/i915/i915_gem_execbuffer.c:1302:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/radeon/radeon_prime.c:69:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
drivers/gpu/drm/nouveau/nouveau_prime.c:70:2: warning: ignoring return value of ‘ww_mutex_lock’, declared with attribute warn_unused_result [-Wunused-result]
... but we cannot just litter the kernel build log with such warnings.
These need to be fixed separately - turn off the warning for now.
Cc: Nicolai Hähnle <nicolai.haehnle@amd.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Leak references by unbalanced get, instead of poking at kref
implementation details.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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For some obscure reason apparmor thinks its needs to locally implement
kref primitives that already exist. Stop doing this.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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By general sentiment kref_sub() is a bad interface, make it go away.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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|
Since we need to change the implementation, stop exposing internals.
Provide kref_read() to read the current reference count; typically
used for debug messages.
Kills two anti-patterns:
atomic_read(&kref->refcount)
kref->refcount.counter
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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|
Since we need to change the implementation, stop exposing internals.
Provide KREF_INIT() to allow static initialization of struct kref.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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|
Add the minimal test running (modprobe test-ww_mutex) to the kselftests
CI framework.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161201114711.28697-9-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Nicolai Hähnle <nhaehnle@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161201114711.28697-8-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Check that ww_mutexes can detect cyclic deadlocks (generalised ABBA
cycles) and resolve them by lock reordering.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Nicolai Hähnle <nhaehnle@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161201114711.28697-7-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Nicolai Hähnle <nhaehnle@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161201114711.28697-6-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Nicolai Hähnle <nhaehnle@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161201114711.28697-5-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Nicolai Hähnle <nhaehnle@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161201114711.28697-4-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Although ww_mutexes degenerate into mutexes, it would be useful to
torture the deadlock handling between multiple ww_mutexes in addition to
torturing the regular mutexes.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Nicolai Hähnle <nhaehnle@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161201114711.28697-3-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
From conflicting macro parameters, passing the wrong name to
__MUTEX_INITIALIZER and a stray '\', #define __WW_MUTEX_INITIALIZER was
very unhappy.
One unnecessary change was to choose to pass &ww_class instead of
implicitly taking the address of the class within the macro.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 1b375dc30710 ("mutex: Move ww_mutex definitions to ww_mutex.h")
Link: http://lkml.kernel.org/r/20161201114711.28697-2-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
It turns out that while GCC-4.4 manages to generate 32x32->64 mult
instructions for the 32bit mul_u64_u32_shr() code, any GCC after that
fails horribly.
Fix this by providing an explicit mul_u32_u32() function which can be
architcture provided.
Reported-by: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Chris Metcalf <cmetcalf@mellanox.com> [for tile]
Cc: Christopher S. Hall <christopher.s.hall@intel.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Laurent Vivier <lvivier@redhat.com>
Cc: Liav Rehana <liavr@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Parit Bhargava <prarit@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161209083011.GD15765@worktop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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|
journal->j_checkpoint_mutex
When an ext4 fs is bogged down by a lot of metadata IOs (in the
reported case, it was deletion of millions of files, but any massive
amount of journal writes would do), after the journal is filled up,
tasks which try to access the filesystem and aren't currently
performing the journal writes end up waiting in
__jbd2_log_wait_for_space() for journal->j_checkpoint_mutex.
Because those mutex sleeps aren't marked as iowait, this condition can
lead to misleadingly low iowait and /proc/stat:procs_blocked. While
iowait propagation is far from strict, this condition can be triggered
fairly easily and annotating these sleeps correctly helps initial
diagnosis quite a bit.
Use the new mutex_lock_io() for journal->j_checkpoint_mutex so that
these sleeps are properly marked as iowait.
Reported-by: Mingbo Wan <mingbo@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-team@fb.com
Link: http://lkml.kernel.org/r/1477673892-28940-5-git-send-email-tj@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
We sometimes end up propagating IO blocking through mutexes; however,
because there currently is no way of annotating mutex sleeps as
iowait, there are cases where iowait and /proc/stat:procs_blocked
report misleading numbers obscuring the actual state of the system.
This patch adds mutex_lock_io() so that mutex sleeps can be marked as
iowait in those cases.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: adilger.kernel@dilger.ca
Cc: jack@suse.com
Cc: kernel-team@fb.com
Cc: mingbo@fb.com
Cc: tytso@mit.edu
Link: http://lkml.kernel.org/r/1477673892-28940-4-git-send-email-tj@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Now that IO schedule accounting is done inside __schedule(),
io_schedule() can be split into three steps - prep, schedule, and
finish - where the schedule part doesn't need any special annotation.
This allows marking a sleep as iowait by simply wrapping an existing
blocking function with io_schedule_prepare() and io_schedule_finish().
Because task_struct->in_iowait is single bit, the caller of
io_schedule_prepare() needs to record and the pass its state to
io_schedule_finish() to be safe regarding nesting. While this isn't
the prettiest, these functions are mostly gonna be used by core
functions and we don't want to use more space for ->in_iowait.
While at it, as it's simple to do now, reimplement io_schedule()
without unnecessarily going through io_schedule_timeout().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: adilger.kernel@dilger.ca
Cc: jack@suse.com
Cc: kernel-team@fb.com
Cc: mingbo@fb.com
Cc: tytso@mit.edu
Link: http://lkml.kernel.org/r/1477673892-28940-3-git-send-email-tj@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
scheduler
For an interface to support blocking for IOs, it must call
io_schedule() instead of schedule(). This makes it tedious to add IO
blocking to existing interfaces as the switching between schedule()
and io_schedule() is often buried deep.
As we already have a way to mark the task as IO scheduling, this can
be made easier by separating out io_schedule() into multiple steps so
that IO schedule preparation can be performed before invoking a
blocking interface and the actual accounting happens inside the
scheduler.
io_schedule_timeout() does the following three things prior to calling
schedule_timeout().
1. Mark the task as scheduling for IO.
2. Flush out plugged IOs.
3. Account the IO scheduling.
done close to the actual scheduling. This patch moves #3 into the
scheduler so that later patches can separate out preparation and
finish steps from io_schedule().
Patch-originally-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: adilger.kernel@dilger.ca
Cc: akpm@linux-foundation.org
Cc: axboe@kernel.dk
Cc: jack@suse.com
Cc: kernel-team@fb.com
Cc: mingbo@fb.com
Cc: tytso@mit.edu
Link: http://lkml.kernel.org/r/20161207204841.GA22296@htj.duckdns.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Turner <pjt@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/e9a4d858-bcf3-36b9-e3a9-449953e34569@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
The update of the share of a cfs_rq is done when its load_avg is updated
but before the group_entity's load_avg has been updated for the past time
slot. This generates wrong load_avg accounting which can be significant
when small tasks are involved in the scheduling.
Let take the example of a task a that is dequeued of its task group A:
root
(cfs_rq)
\
(se)
A
(cfs_rq)
\
(se)
a
Task "a" was the only task in task group A which becomes idle when a is
dequeued.
We have the sequence:
- dequeue_entity a->se
- update_load_avg(a->se)
- dequeue_entity_load_avg(A->cfs_rq, a->se)
- update_cfs_shares(A->cfs_rq)
A->cfs_rq->load.weight == 0
A->se->load.weight is updated with the new share (0 in this case)
- dequeue_entity A->se
- update_load_avg(A->se) but its weight is now null so the last time
slot (up to a tick) will be accounted with a weight of 0 instead of
its real weight during the time slot. The last time slot will be
accounted as an idle one whereas it was a running one.
If the running time of task a is short enough that no tick happens when it
runs, all running time of group entity A->se will be accounted as idle
time.
Instead, we should update the share of a cfs_rq (in fact the weight of its
group entity) only after having updated the load_avg of the group_entity.
update_cfs_shares() now takes the sched_entity as a parameter instead of the
cfs_rq, and the weight of the group_entity is updated only once its load_avg
has been synced with current time.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: pjt@google.com
Link: http://lkml.kernel.org/r/1482335426-7664-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Documentation/scheduler/completion.txt says this about complete_all():
"calls complete_all() to signal all current and future waiters."
Which doesn't strictly match the current semantics. Currently
complete_all() is equivalent to UINT_MAX/2 complete() invocations,
which is distinctly less than 'all current and future waiters'
(enumerable vs innumerable), although it has worked in practice.
However, Dmitry had a weird case where it might matter, so change
completions to use saturation semantics for complete()/complete_all().
Once done hits UINT_MAX (and complete_all() sets it there) it will
never again be decremented.
Requested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: der.herr@hofr.at
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
This patch allows for reading the current (leftover) runtime and
absolute deadline of a SCHED_DEADLINE task through /proc/*/sched
(entries dl.runtime and dl.deadline), while debugging/testing.
Signed-off-by: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juri Lelli <juri.lelli@arm.com>
Reviewed-by: Luca Abeni <luca.abeni@unitn.it>
Acked-by: Daniel Bistrot de Oliveira <danielbristot@gmail.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1477473437-10346-2-git-send-email-tommaso.cucinotta@sssup.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
When switching between the unstable and stable variants it is
currently possible that clock discontinuities occur.
And while these will mostly be 'small', attempt to do better.
As observed on my IVB-EP, the sched_clock() is ~1.5s ahead of the
ktime_get_ns() based timeline at the point of switchover
(sched_clock_init_late()) after SMP bringup.
Equally, when the TSC is later found to be unstable -- typically
because SMM tries to hide its SMI latencies by mucking with the TSC --
we want to avoid large jumps.
Since the clocksource watchdog reports the issue after the fact we
cannot exactly fix up time, but since SMI latencies are typically
small (~10ns range), the discontinuity is mainly due to drift between
sched_clock() and ktime_get_ns() (which on my desktop is ~79s over
24days).
I dislike this patch because it adds overhead to the good case in
favour of dealing with badness. But given the widespread failure of
TSC stability this is worth it.
Note that in case the TSC makes drastic jumps after SMP bringup we're
still hosed. There's just not much we can do in that case without
stupid overhead.
If we were to somehow expose tsc_clocksource_reliable (which is hard
because this code is also used on ia64 and parisc) we could avoid some
of the newly introduced overhead.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Currently we switch to the stable sched_clock if we guess the TSC is
usable, and then switch back to the unstable path if it turns out TSC
isn't stable during SMP bringup after all.
Delay switching to the stable path until after SMP bringup is
complete. This way we'll avoid switching during the time we detect the
worst of the TSC offences.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
sched_clock was still using the deprecated static_key interface.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
PeterZ reported that we'd fail to mark the TSC unstable when the
clocksource watchdog finds it unsuitable.
Allow a clocksource to run a custom action when its being marked
unstable and hook up the TSC unstable code.
Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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There's no diagnostic checks for figuring out when we've accidentally
missed update_rq_clock() calls. Let's add some by piggybacking on the
rq_*pin_lock() wrappers.
The idea behind the diagnostic checks is that upon pining rq lock the
rq clock should be updated, via update_rq_clock(), before anybody
reads the clock with rq_clock() or rq_clock_task().
The exception to this rule is when updates have explicitly been
disabled with the rq_clock_skip_update() optimisation.
There are some functions that only unpin the rq lock in order to grab
some other lock and avoid deadlock. In that case we don't need to
update the clock again and the previous diagnostic state can be
carried over in rq_repin_lock() by saving the state in the rq_flags
context.
Since this patch adds a new clock update flag and some already exist
in rq::clock_skip_update, that field has now been renamed. An attempt
has been made to keep the flag manipulation code small and fast since
it's used in the heart of the __schedule() fast path.
For the !CONFIG_SCHED_DEBUG case the only object code change (other
than addresses) is the following change to reset RQCF_ACT_SKIP inside
of __schedule(),
- c7 83 38 09 00 00 00 movl $0x0,0x938(%rbx)
- 00 00 00
+ 83 a3 38 09 00 00 fc andl $0xfffffffc,0x938(%rbx)
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Yuyang Du <yuyang.du@intel.com>
Link: http://lkml.kernel.org/r/20160921133813.31976-8-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Address this rq-clock update bug:
WARNING: CPU: 30 PID: 195 at ../kernel/sched/sched.h:797 set_next_entity()
rq->clock_update_flags < RQCF_ACT_SKIP
Call Trace:
dump_stack()
__warn()
warn_slowpath_fmt()
set_next_entity()
? _raw_spin_lock()
set_curr_task_fair()
set_user_nice.part.85()
set_user_nice()
create_worker()
worker_thread()
kthread()
ret_from_fork()
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Add the update_rq_clock() call at the top of the callstack instead of
at the bottom where we find it missing, this to aid later effort to
minimize the number of update_rq_lock() calls.
WARNING: CPU: 30 PID: 194 at ../kernel/sched/sched.h:797 assert_clock_updated()
rq->clock_update_flags < RQCF_ACT_SKIP
Call Trace:
dump_stack()
__warn()
warn_slowpath_fmt()
assert_clock_updated.isra.63.part.64()
can_migrate_task()
load_balance()
pick_next_task_fair()
__schedule()
schedule()
worker_thread()
kthread()
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Instead of adding the update_rq_clock() all the way at the bottom of
the callstack, add one at the top, this to aid later effort to
minimize update_rq_lock() calls.
WARNING: CPU: 0 PID: 1 at ../kernel/sched/sched.h:797 detach_task_cfs_rq()
rq->clock_update_flags < RQCF_ACT_SKIP
Call Trace:
dump_stack()
__warn()
warn_slowpath_fmt()
detach_task_cfs_rq()
switched_from_fair()
__sched_setscheduler()
_sched_setscheduler()
sched_set_stop_task()
cpu_stop_create()
__smpboot_create_thread.part.2()
smpboot_register_percpu_thread_cpumask()
cpu_stop_init()
do_one_initcall()
? print_cpu_info()
kernel_init_freeable()
? rest_init()
kernel_init()
ret_from_fork()
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Address this rq-clock update bug:
WARNING: CPU: 0 PID: 0 at ../kernel/sched/sched.h:797 post_init_entity_util_avg()
rq->clock_update_flags < RQCF_ACT_SKIP
Call Trace:
__warn()
post_init_entity_util_avg()
wake_up_new_task()
_do_fork()
kernel_thread()
rest_init()
start_kernel()
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Future patches will emit warnings if rq_clock() is called before
update_rq_clock() inside a rq_pin_lock()/rq_unpin_lock() pair.
Since there is only one caller of idle_balance() we can push the
unpin/repin there.
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Yuyang Du <yuyang.du@intel.com>
Link: http://lkml.kernel.org/r/20160921133813.31976-7-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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rq_clock() is called from sched_info_{depart,arrive}() after resetting
RQCF_ACT_SKIP but prior to a call to update_rq_clock().
In preparation for pending patches that check whether the rq clock has
been updated inside of a pin context before rq_clock() is called, move
the reset of rq->clock_skip_update immediately before unpinning the rq
lock.
This will avoid the new warnings which check if update_rq_clock() is
being actively skipped.
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Yuyang Du <yuyang.du@intel.com>
Link: http://lkml.kernel.org/r/20160921133813.31976-6-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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In preparation for adding diagnostic checks to catch missing calls to
update_rq_clock(), provide wrappers for (re)pinning and unpinning
rq->lock.
Because the pending diagnostic checks allow state to be maintained in
rq_flags across pin contexts, swap the 'struct pin_cookie' arguments
for 'struct rq_flags *'.
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Yuyang Du <yuyang.du@intel.com>
Link: http://lkml.kernel.org/r/20160921133813.31976-5-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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