- 12 Jul, 2018 21 commits
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Paul E. McKenney authored
SRCU has long used ->srcu_gp_seq, and now RCU uses ->gp_seq. This commit therefore moves the rcutorture_get_gp_data() function from a ->gpnum / ->completed pair to ->gp_seq. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit makes the RCU CPU stall-warning code in print_other_cpu_stall(), print_cpu_stall(), and check_cpu_stall() use ->gp_seq instead of ->gpnum and ->completed. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit converts the grace-period request code paths from ->completed and ->gpnum to ->gp_seq. The need_future_gp_element() macro encapsulates the shift operation required to use ->gp_seq as an index to the ->need_future_gp[] array. The rcu_cbs_completed() function is removed in favor of the rcu_seq_snap() function. The rcu_start_this_gp() gets some temporary consistency checks and uses rcu_seq_done(), rcu_seq_current(), rcu_seq_state(), and rcu_gp_in_progress() in place of the earlier open-coded comparisons of ->gpnum and ->completed. The rcu_future_gp_cleanup() function replaces use of ->completed with ->gp_seq. The rcu_accelerate_cbs() function replaces a call to rcu_cbs_completed() with one to rcu_seq_snap(). The rcu_advance_cbs() function replaces an access to >completed with one to ->gp_seq and adds some temporary warnings. The rcu_nocb_wait_gp() function replaces a call to rcu_cbs_completed() with one to rcu_seq_snap() and an open-coded comparison with rcu_seq_done(). The temporary warnings will be removed when the various ->gpnum and ->completed fields are removed. Their purpose is to locate code who might still be using ->gpnum and ->completed. (Much easier that way than trying to trace down the causes of too-short grace periods and grace-period hangs!) Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit switches the quiescent-state no-backtracking checks from ->gpnum and ->completed to ->gp_seq. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit switches the interrupt-disabled detection mechanism to ->gp_seq. This mechanism is used as part of RCU CPU stall warnings, and detects cases where the stall is due to a CPU having interrupts disabled. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit makes rcu_gp_in_progress() use ->gp_seq instead of ->completed and ->gpnum. The READ_ONCE() invocations are buried in rcu_seq_current(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit makes rcu_try_advance_all_cbs() use ->gp_seq. It uses rcu_seq_ctr() in order to shift away the state bits, so that the low-order bits of the result may safely be used to index ->nocb_gp_wq[]. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit makes rcu_try_advance_all_cbs() use ->gp_seq, with the exception of tracing, which will be converted later. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit makes rcu_implicit_dynticks_qs() use ->gp_seq, with the exception of tracing, which will be converted later. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit converts rcu_gpnum_ovf() to use ->gp_seq instead of ->gpnum. Same size unsigned long, so same approach. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit moves __note_gp_changes(), note_gp_changes(), and __rcu_pending() to ->gp_seq, creating new rcu_seq_completed_gp() and rcu_seq_new_gp() functions for this purpose. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: Reinstate "cpuend: trace as suggested by Joel Fernandes. ]
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Paul E. McKenney authored
This commit converts get_state_synchronize_rcu(), cond_synchronize_rcu(), get_state_synchronize_sched(), and cond_synchronize_sched() from ->gpnum and ->completed to ->gp_seq. Note that this also introduces a full memory barrier in the already-done paths off cond_synchronize_rcu() and cond_synchronize_sched(), as work with LKMM indicates that the earlier smp_load_acquire() were insufficiently strong in some situations where these two functions were called just as the grace period ended. In such cases, these two functions would not gain the benefit of memory ordering at the end of the grace period. Please note that the performance impact is negligible, as you shouldn't be using either function anywhere near a fastpath in any case. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit switches the functions reporting quiescent states from use of ->gpnum to ->gp_seq. In either case, the point is to handle races where a given grace period ends before a quiescent state can be reported. Failing to catch these races would result in too-short grace periods, hence the checking. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit switches rcu_check_gp_kthread_starvation() from printing ->gpnum and ->completed to printing ->gp_seq upon detecting a starving RCU grace-period kthread during an RCU CPU stall warning. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
The rcutorture test invokes rcu_batches_started(), rcu_batches_completed(), rcu_batches_started_bh(), rcu_batches_completed_bh(), rcu_batches_started_sched(), and rcu_batches_completed_sched() to do grace-period consistency checks, and rcuperf uses the _completed variants for statistics. These functions use ->gpnum and ->completed. This commit therefore replaces them with rcu_get_gp_seq(), rcu_bh_get_gp_seq(), and rcu_sched_get_gp_seq(), adjusting rcutorture and rcuperf to make use of them. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit moves rcu_gp_slow() to ->gp_seq. This function only uses the grace-period number to modulate delay, so rcu_seq_ctr(rsp->gp_seq) gets the same effect, at least in cases where the delay is to happen more than four times per wrap of an unsigned long. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit adds grace-period sequence numbers (->gp_seq) to the rcu_state, rcu_node, and rcu_data structures, and updates them. It also checks for consistency between rsp->gpnum and rsp->gp_seq. These ->gp_seq counters will eventually replace the existing ->gpnum and ->completed counters, allowing a single memory access to determine whether or not a grace period is in progress and if so, which one. This in turn will enable changes that will reduce ->lock contention on the leaf rcu_node structures. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
Merge branches 'expedited.2018.07.12a', 'fixes.2018.07.12a', 'srcu.2018.06.25b' and 'torture.2018.06.25b' into HEAD expedited.2018.07.12a: Expedited grace-period updates. fixes.2018.07.12a: Pre-gp_seq miscellaneous fixes. srcu.2018.06.25b: SRCU updates. torture.2018.06.25b: Pre-gp_seq torture-test updates.
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Paul E. McKenney authored
At the end of rcu_gp_cleanup(), if another grace period is needed, but not via rcu_accelerate_cbs(), the ->gp_flags field is written twice, once when making the new grace-period request, and once when clearing all other types of requests. This commit therefore adds an else-clause to avoid this double write. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit causes a splat if RCU is idle and a request for a new grace period is ignored for more than one second. This splat normally indicates that some code path asked for a new grace period, but failed to wake up the RCU grace-period kthread. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: Fix bug located by Dan Carpenter and his static checker. ] [ paulmck: Fix self-deadlock bug located 0day test robot. ] [ paulmck: Disable unless CONFIG_PROVE_RCU=y. ]
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Boqun Feng authored
Currently, the parallelized initialization of expedited grace periods uses the workqueue associated with each rcu_node structure's ->grplo field. This works fine unless that CPU is offline. This commit therefore uses the CPU corresponding to the lowest-numbered online CPU, or just queues the work on WORK_CPU_UNBOUND if there are no online CPUs corresponding to this rcu_node structure. Note that this patch uses cpu_is_offline() instead of the usual approach of checking bits in the rcu_node structure's ->qsmaskinitnext field. This is safe because preemption is disabled across both the cpu_is_offline() check and the call to queue_work_on(). Signed-off-by: Boqun Feng <boqun.feng@gmail.com> [ paulmck: Disable preemption to close offline race window. ] Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: Apply Peter Zijlstra feedback on CPU selection. ] Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
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- 26 Jun, 2018 3 commits
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Paul E. McKenney authored
There is a two-jiffy delay between the time that a CPU will self-report an RCU CPU stall warning and the time that some other CPU will report a warning on behalf of the first CPU. This has worked well in the past, but on busy systems, it is possible for the two warnings to overlap, which makes interpreting them extremely difficult. This commit therefore uses a cmpxchg-based timing decision that allows only one report in a given one-minute period (assuming default stall-warning Kconfig parameters). This approach will of course fail if you are seeing minute-long vCPU preemption, but in that case the overlapping RCU CPU stall warnings are the least of your worries. Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Boqun Feng authored
Sparse reported this: | kernel/rcu/tree_plugin.h:814:9: warning: incorrect type in argument 1 (different modifiers) | kernel/rcu/tree_plugin.h:814:9: expected struct lockdep_map const *lock | kernel/rcu/tree_plugin.h:814:9: got struct lockdep_map [noderef] *<noident> This is caused by using vanilla lockdep annotations on rcu_node::lock, and that requires accessing ->lock of rcu_node directly. However we need to keep rcu_node::lock __private to avoid breaking its extra ordering guarantee. And we have a dedicated lockdep annotation for rcu_node::lock, so use it. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
The WARN_ON_ONCE(rcu_preempt_blocked_readers_cgp()) in rcu_gp_cleanup() triggers (inexplicably, of course) every so often. This commit therefore extracts more information. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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- 25 Jun, 2018 10 commits
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Paul E. McKenney authored
This commit adds "#define pr_fmt(fmt) fmt" to the torture-test files in order to keep the current dmesg format. Once Joe's commits have hit mainline, these definitions will be changed in order to automatically generate the dmesg line prefix that the scripts expect. This will have the beneficial side-effect of allowing printk() formats to be used more widely and of shortening some pr_*() lines. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Joe Perches <joe@perches.com>
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Paul E. McKenney authored
Some bugs reproduce quickly only at high CPU-hotplug rates, so the rcutorture TREE03 scenario now has only 200 milliseconds spacing between CPU-hotplug operations. At this rate, the torture-test pair of console messages per operation becomes a bit voluminous. This commit therefore converts the torture-test set of "verbose" kernel-boot arguments from bool to int, and prints the extra console messages only when verbose=2. The default is still verbose=1. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
Although warnings about close calls are printed by kvm-recheck.sh, kvm-find-errors.sh currently ignores them. This could easily result in someone failing to investigate close calls, so this commit makes them visible to kvm-find-errors.sh. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
The TREE08-T.boot file was used to provide alternative options for debugging, but things have changed, it has not kept up, and it has not been used or missed. This commit therefore removes it. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
The torture scripting currently builds each kernel from a set of parallel runs in its own build directory. This can waste quite a bit of space when running large numbers of concurrent scenarios, and pointlessly given that the builds are run sequentially (albeit with a largish -j number passed to "make"). This commit therefore places all build-command output in the results directory, then does all builds in a single "b1" build directory. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
Joel Fernandes is using SRCU to protect from-idle tracepoints, which requires notrace variants of srcu_read_lock() and srcu_read_unlock() in order to avoid problems with tracepoints in lockdep. This commit therefore adds srcu_read_lock_notrace() and srcu_read_unlock_notrace(). [1] http://lkml.kernel.org/r/20180427042656.190746-1-joelaf@google.comReported-by: Joel Fernandes <joelaf@google.com> Intermittently-reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit adds the address of the first callback to the per-CPU rcutorture output in order to allow lost wakeups to be more efficiently tracked down. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit updates the header comment of srcu_funnel_gp_start() to document the fact that srcu_funnel_gp_start() does the work of srcu_funnel_exp_start(), in some cases by invoking it directly. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
This commit simply changes some copy-pasta call_rcu() instances to the correct call_srcu(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
During expedited grace-period initialization, a work item is scheduled for each leaf rcu_node structure. However, that initialization code is itself (normally) executing from a workqueue, so one of the leaf rcu_node structures could just as well be handled by that pre-existing workqueue, and with less overhead. This commit therefore uses a shiny new rcu_is_leaf_node() macro to execute the last leaf rcu_node structure's initialization directly from the pre-existing workqueue. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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- 16 Jun, 2018 6 commits
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Linus Torvalds authored
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git://git.kernel.dk/linux-blockLinus Torvalds authored
Pull block fixes from Jens Axboe: "A collection of fixes that should go into -rc1. This contains: - bsg_open vs bsg_unregister race fix (Anatoliy) - NVMe pull request from Christoph, with fixes for regressions in this window, FC connect/reconnect path code unification, and a trace point addition. - timeout fix (Christoph) - remove a few unused functions (Christoph) - blk-mq tag_set reinit fix (Roman)" * tag 'for-linus-20180616' of git://git.kernel.dk/linux-block: bsg: fix race of bsg_open and bsg_unregister block: remov blk_queue_invalidate_tags nvme-fabrics: fix and refine state checks in __nvmf_check_ready nvme-fabrics: handle the admin-only case properly in nvmf_check_ready nvme-fabrics: refactor queue ready check blk-mq: remove blk_mq_tagset_iter nvme: remove nvme_reinit_tagset nvme-fc: fix nulling of queue data on reconnect nvme-fc: remove reinit_request routine blk-mq: don't time out requests again that are in the timeout handler nvme-fc: change controllers first connect to use reconnect path nvme: don't rely on the changed namespace list log nvmet: free smart-log buffer after use nvme-rdma: fix error flow during mapping request data nvme: add bio remapping tracepoint nvme: fix NULL pointer dereference in nvme_init_subsystem blk-mq: reinit q->tag_set_list entry only after grace period
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git://linuxtv.org/mchehab/experimentalLinus Torvalds authored
Pull documentation fixes from Mauro Carvalho Chehab: "This solves a series of broken links for files under Documentation, and improves a script meant to detect such broken links (see scripts/documentation-file-ref-check). The changes on this series are: - can.rst: fix a footnote reference; - crypto_engine.rst: Fix two parsing warnings; - Fix a lot of broken references to Documentation/*; - improve the scripts/documentation-file-ref-check script, in order to help detecting/fixing broken references, preventing false-positives. After this patch series, only 33 broken references to doc files are detected by scripts/documentation-file-ref-check" * tag 'docs-broken-links' of git://linuxtv.org/mchehab/experimental: (26 commits) fix a series of Documentation/ broken file name references Documentation: rstFlatTable.py: fix a broken reference ABI: sysfs-devices-system-cpu: remove a broken reference devicetree: fix a series of wrong file references devicetree: fix name of pinctrl-bindings.txt devicetree: fix some bindings file names MAINTAINERS: fix location of DT npcm files MAINTAINERS: fix location of some display DT bindings kernel-parameters.txt: fix pointers to sound parameters bindings: nvmem/zii: Fix location of nvmem.txt docs: Fix more broken references scripts/documentation-file-ref-check: check tools/*/Documentation scripts/documentation-file-ref-check: get rid of false-positives scripts/documentation-file-ref-check: hint: dash or underline scripts/documentation-file-ref-check: add a fix logic for DT scripts/documentation-file-ref-check: accept more wildcards at filenames scripts/documentation-file-ref-check: fix help message media: max2175: fix location of driver's companion documentation media: v4l: fix broken video4linux docs locations media: dvb: point to the location of the old README.dvb-usb file ...
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git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fsLinus Torvalds authored
Pull fsnotify updates from Jan Kara: "fsnotify cleanups unifying handling of different watch types. This is the shortened fsnotify series from Amir with the last five patches pulled out. Amir has modified those patches to not change struct inode but obviously it's too late for those to go into this merge window" * tag 'fsnotify_for_v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: fsnotify: add fsnotify_add_inode_mark() wrappers fanotify: generalize fanotify_should_send_event() fsnotify: generalize send_to_group() fsnotify: generalize iteration of marks by object type fsnotify: introduce marks iteration helpers fsnotify: remove redundant arguments to handle_event() fsnotify: use type id to identify connector object type
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git://github.com/bzolnier/linuxLinus Torvalds authored
Pull fbdev updates from Bartlomiej Zolnierkiewicz: "There is nothing really major here, few small fixes, some cleanups and dead drivers removal: - mark omapfb drivers as orphans in MAINTAINERS file (Tomi Valkeinen) - add missing module license tags to omap/omapfb driver (Arnd Bergmann) - add missing GPIOLIB dependendy to omap2/omapfb driver (Arnd Bergmann) - convert savagefb, aty128fb & radeonfb drivers to use msleep & co. (Jia-Ju Bai) - allow COMPILE_TEST build for viafb driver (media part was reviewed by media subsystem Maintainer) - remove unused MERAM support from sh_mobile_lcdcfb and shmob-drm drivers (drm parts were acked by shmob-drm driver Maintainer) - remove unused auo_k190xfb drivers - misc cleanups (Souptick Joarder, Wolfram Sang, Markus Elfring, Andy Shevchenko, Colin Ian King)" * tag 'fbdev-v4.18' of git://github.com/bzolnier/linux: (26 commits) fb_omap2: add gpiolib dependency video/omap: add module license tags MAINTAINERS: make omapfb orphan video: fbdev: pxafb: match_string() conversion fixup video: fbdev: nvidia: fix spelling mistake: "scaleing" -> "scaling" video: fbdev: fix spelling mistake: "frambuffer" -> "framebuffer" video: fbdev: pxafb: Convert to use match_string() helper video: fbdev: via: allow COMPILE_TEST build video: fbdev: remove unused sh_mobile_meram driver drm: shmobile: remove unused MERAM support video: fbdev: sh_mobile_lcdcfb: remove unused MERAM support video: fbdev: remove unused auo_k190xfb drivers video: omap: Improve a size determination in omapfb_do_probe() video: sm501fb: Improve a size determination in sm501fb_probe() video: fbdev-MMP: Improve a size determination in path_init() video: fbdev-MMP: Delete an error message for a failed memory allocation in two functions video: auo_k190x: Delete an error message for a failed memory allocation in auok190x_common_probe() video: sh_mobile_lcdcfb: Delete an error message for a failed memory allocation in two functions video: sh_mobile_meram: Delete an error message for a failed memory allocation in sh_mobile_meram_probe() video: fbdev: sh_mobile_meram: Drop SUPERH platform dependency ...
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds authored
Pull AFS updates from Al Viro: "Assorted AFS stuff - ended up in vfs.git since most of that consists of David's AFS-related followups to Christoph's procfs series" * 'afs-proc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: afs: Optimise callback breaking by not repeating volume lookup afs: Display manually added cells in dynamic root mount afs: Enable IPv6 DNS lookups afs: Show all of a server's addresses in /proc/fs/afs/servers afs: Handle CONFIG_PROC_FS=n proc: Make inline name size calculation automatic afs: Implement network namespacing afs: Mark afs_net::ws_cell as __rcu and set using rcu functions afs: Fix a Sparse warning in xdr_decode_AFSFetchStatus() proc: Add a way to make network proc files writable afs: Rearrange fs/afs/proc.c to remove remaining predeclarations. afs: Rearrange fs/afs/proc.c to move the show routines up afs: Rearrange fs/afs/proc.c by moving fops and open functions down afs: Move /proc management functions to the end of the file
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