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| author |   Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-03 14:31:33 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-03 14:31:33 -0700 |
| commit | 8f0cb6660acb0d4756df880a3e60e73daa9c244e (patch) | |
| tree | 9f14396bed65f82b94f7bb2425ffb2f0cbd4519a /Documentation/RCU/Design | |
| parent | Merge tag 'core-headers-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (diff) | |
| parent | Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu (diff) | |
| download | linux-dev-8f0cb6660acb0d4756df880a3e60e73daa9c244e.tar.xz linux-dev-8f0cb6660acb0d4756df880a3e60e73daa9c244e.zip | |
Merge tag 'core-rcu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:
- kfree_rcu updates
- RCU tasks updates
- Read-side scalability tests
- SRCU updates
- Torture-test updates
- Documentation updates
- Miscellaneous fixes
* tag 'core-rcu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (109 commits)
torture: Remove obsolete "cd $KVM"
torture: Avoid duplicate specification of qemu command
torture: Dump ftrace at shutdown only if requested
torture: Add kvm-tranform.sh script for qemu-cmd files
torture: Add more tracing crib notes to kvm.sh
torture: Improve diagnostic for KCSAN-incapable compilers
torture: Correctly summarize build-only runs
torture: Pass --kmake-arg to all make invocations
rcutorture: Check for unwatched readers
torture: Abstract out console-log error detection
torture: Add a stop-run capability
torture: Create qemu-cmd in --buildonly runs
rcu/rcutorture: Replace 0 with false
torture: Add --allcpus argument to the kvm.sh script
torture: Remove whitespace from identify_qemu_vcpus output
rcutorture: NULL rcu_torture_current earlier in cleanup code
rcutorture: Handle non-statistic bang-string error messages
torture: Set configfile variable to current scenario
rcutorture: Add races with task-exit processing
locktorture: Use true and false to assign to bool variables
...
Diffstat (limited to 'Documentation/RCU/Design')
| -rw-r--r-- | Documentation/RCU/Design/Requirements/Requirements.rst | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/Documentation/RCU/Design/Requirements/Requirements.rst b/Documentation/RCU/Design/Requirements/Requirements.rst index 50d5c43c48b0..8f41ad0aa753 100644 --- a/Documentation/RCU/Design/Requirements/Requirements.rst +++ b/Documentation/RCU/Design/Requirements/Requirements.rst @@ -2583,7 +2583,12 @@ not work to have these markers in the trampoline itself, because there would need to be instructions following ``rcu_read_unlock()``. Although ``synchronize_rcu()`` would guarantee that execution reached the ``rcu_read_unlock()``, it would not be able to guarantee that execution -had completely left the trampoline. +had completely left the trampoline. Worse yet, in some situations +the trampoline's protection must extend a few instructions *prior* to +execution reaching the trampoline. For example, these few instructions +might calculate the address of the trampoline, so that entering the +trampoline would be pre-ordained a surprisingly long time before execution +actually reached the trampoline itself. The solution, in the form of `Tasks RCU <https://lwn.net/Articles/607117/>`__, is to have implicit read-side |