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| author | Joel Fernandes <[email protected]> | 2025-07-15 20:01:51 +0000 |
|---|---|---|
| committer | Paul E. McKenney <[email protected]> | 2025-07-17 19:11:13 +0000 |
| commit | cf4fc66746e344181f41604066659073dbb8aaf0 (patch) | |
| tree | 6a30070c53af23fac7042f45a8839e3716ee18d3 /rust/helpers/device.c | |
| parent | stop_machine: Improve kernel-doc function-header comments (diff) | |
| download | kernel-cf4fc66746e344181f41604066659073dbb8aaf0.tar.gz kernel-cf4fc66746e344181f41604066659073dbb8aaf0.zip | |
smp: Document preemption and stop_machine() mutual exclusion
Recently while revising RCU's cpu online checks, there was some discussion
around how IPIs synchronize with hotplug.
Add comments explaining how preemption disable creates mutual exclusion with
CPU hotplug's stop_machine mechanism. The key insight is that stop_machine()
atomically updates CPU masks and flushes IPIs with interrupts disabled, and
cannot proceed while any CPU (including the IPI sender) has preemption
disabled.
[ Apply peterz feedback. ]
Cc: Andrea Righi <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Peter Zijlstra (Intel) <[email protected]>
Cc: [email protected]
Acked-by: Paul E. McKenney <[email protected]>
Co-developed-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Joel Fernandes <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Diffstat (limited to 'rust/helpers/device.c')
0 files changed, 0 insertions, 0 deletions