On Thu, Sep 01, 2022 at 10:17:02PM +0000, Joel Fernandes (Google) wrote: > Here is v5 of call_rcu_lazy() based on the latest RCU -dev branch. Main changes are: > - moved length field into rcu_data (Frederic suggestion) > - added new traces to aid debugging and testing. > - the new trace patch (along with the rcuscale and rcutorture tests) > gives confidence that the patches work well. Also it is tested on > real ChromeOS hardware and the boot time is looking good even though > lazy callbacks are being queued (i.e. the lazy ones do not effect the > synchronous non-lazy ones that effect boot time) > - rewrote some parts of the core patch. > - for rcutop, please apply the diff in the following link to the BCC repo: > https://lore.kernel.org/r/Yn+79v4q+1c9lXdc@xxxxxxxxxx > Then, cd libbpf-tools/ and run make to build the rcutop static binary. > (If you need an x86 binary, ping me and I'll email you). > In the future, I will attempt to make rcutop built within the kernel repo. > This is already done for another tool (see tools/bpf/runqslower) so is doable. > > The 2 mm patches are what Vlastimil pulled into slab-next. I included them in > this series so that the tracing patch builds. > > Previous series was posted here: > https://lore.kernel.org/all/20220713213237.1596225-1-joel@xxxxxxxxxxxxxxxxx/ > > Linked below [1] is some power data I collected with Turbostat on an x86 > ChromeOS ADL machine. The numbers are not based on -next, but rather 5.19 > kernel as that's what booted on my ChromeOS machine). > > These are output by Turbostat, by running: > turbostat -S -s PkgWatt,CorWatt --interval 5 > PkgWatt - summary of package power in Watts 5 second interval. > CoreWatt - summary of core power in Watts 5 second interval. > > [1] https://lore.kernel.org/r/b4145008-6840-fc69-a6d6-e38bc218009d@xxxxxxxxxxxxxxxxx Thank you for all your work on this! I have pulled these in for testing and review. Some work is required for them to be ready for mainline. > Joel Fernandes (Google) (15): I took these: > rcu/tree: Use READ_ONCE() for lockless read of rnp->qsmask > rcu: Fix late wakeup when flush of bypass cblist happens > rcu: Move trace_rcu_callback() before bypassing > rcu: Introduce call_rcu_lazy() API implementation You and Frederic need to come to agreement on "rcu: Fix late wakeup when flush of bypass cblist happens". These have some difficulties, so I put them on top of the stack: > rcu: Add per-CB tracing for queuing, flush and invocation. This one breaks 32-bit MIPS. > rcuscale: Add laziness and kfree tests I am concerned that this one has OOM problems. > rcutorture: Add test code for call_rcu_lazy() This one does not need a separate scenario, but instead a separate rcutorture.gp_lazy boot parameter. For a rough template for this sort of change, please see the rcutorture changes in this commit: 76ea364161e7 ("rcu: Add full-sized polling for start_poll()") The key point is that every rcutorture.torture_type=rcu test then becomes a call_rcu_lazy() test. (Unless explicitly overridden.) I took these, though they need go up their respective trees or get acks from their respective maintainers. > fs: Move call_rcu() to call_rcu_lazy() in some paths > cred: Move call_rcu() to call_rcu_lazy() > security: Move call_rcu() to call_rcu_lazy() > net/core: Move call_rcu() to call_rcu_lazy() > kernel: Move various core kernel usages to call_rcu_lazy() > lib: Move call_rcu() to call_rcu_lazy() > i915: Move call_rcu() to call_rcu_lazy() > fork: Move thread_stack_free_rcu() to call_rcu_lazy() > > Vineeth Pillai (1): I took this: > rcu: shrinker for lazy rcu > > Vlastimil Babka (2): As noted earlier, I took these strictly for testing. I do not expect to push them into -next, let alone into mainline. > mm/slub: perform free consistency checks before call_rcu > mm/sl[au]b: rearrange struct slab fields to allow larger rcu_head These all are on -rcu not-yet-for-mainline branch lazy.2022.09.03b. Thanx, Paul > drivers/gpu/drm/i915/gem/i915_gem_object.c | 2 +- > fs/dcache.c | 4 +- > fs/eventpoll.c | 2 +- > fs/file_table.c | 2 +- > fs/inode.c | 2 +- > include/linux/rcupdate.h | 6 + > include/linux/types.h | 44 +++ > include/trace/events/rcu.h | 69 ++++- > kernel/cred.c | 2 +- > kernel/exit.c | 2 +- > kernel/fork.c | 6 +- > kernel/pid.c | 2 +- > kernel/rcu/Kconfig | 19 ++ > kernel/rcu/rcu.h | 12 + > kernel/rcu/rcu_segcblist.c | 23 +- > kernel/rcu/rcu_segcblist.h | 8 + > kernel/rcu/rcuscale.c | 74 ++++- > kernel/rcu/rcutorture.c | 60 +++- > kernel/rcu/tree.c | 187 ++++++++---- > kernel/rcu/tree.h | 13 +- > kernel/rcu/tree_nocb.h | 282 +++++++++++++++--- > kernel/time/posix-timers.c | 2 +- > lib/radix-tree.c | 2 +- > lib/xarray.c | 2 +- > mm/slab.h | 54 ++-- > mm/slub.c | 20 +- > net/core/dst.c | 2 +- > security/security.c | 2 +- > security/selinux/avc.c | 4 +- > .../selftests/rcutorture/configs/rcu/CFLIST | 1 + > .../selftests/rcutorture/configs/rcu/TREE11 | 18 ++ > .../rcutorture/configs/rcu/TREE11.boot | 8 + > 32 files changed, 783 insertions(+), 153 deletions(-) > create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/TREE11 > create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/TREE11.boot > > -- > 2.37.2.789.g6183377224-goog >
