linux/drivers/char/random.c
Linus Torvalds 97851c6016 lib/ratelimit: Reduce false-positive and silent misses
Changes
 -------
 
 * Reduce open-coded use of ratelimit_state structure fields.
 * Convert the ->missed field to atomic_t.
 * Count misses that are due to lock contention.
 * Eliminate jiffies=0 special case.
 * Reduce ___ratelimit() false-positive rate limiting (Petr Mladek).
 * Allow zero ->burst to hard-disable rate limiting.
 * Optimize away atomic operations when a miss is guaranteed.
 * Warn if ->interval or ->burst are negative (Petr Mladek).
 * Simplify the resulting code.
 
 A smoke test and stress test have been created, but they are not yet ready
 for mainline.  With luck, we will offer them for the v6.17 merge window.
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Merge tag 'ratelimit.2025.05.25a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull rate-limit updates from Paul McKenney:
 "lib/ratelimit: Reduce false-positive and silent misses:

   - Reduce open-coded use of ratelimit_state structure fields.

   - Convert the ->missed field to atomic_t.

   - Count misses that are due to lock contention.

   - Eliminate jiffies=0 special case.

   - Reduce ___ratelimit() false-positive rate limiting (Petr Mladek).

   - Allow zero ->burst to hard-disable rate limiting.

   - Optimize away atomic operations when a miss is guaranteed.

   - Warn if ->interval or ->burst are negative (Petr Mladek).

   - Simplify the resulting code.

  A smoke test and stress test have been created, but they are not yet
  ready for mainline. With luck, we will offer them for the v6.17 merge
  window"

* tag 'ratelimit.2025.05.25a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  ratelimit: Drop redundant accesses to burst
  ratelimit: Use nolock_ret restructuring to collapse common case code
  ratelimit: Use nolock_ret label to collapse lock-failure code
  ratelimit: Use nolock_ret label to save a couple of lines of code
  ratelimit: Simplify common-case exit path
  ratelimit: Warn if ->interval or ->burst are negative
  ratelimit: Avoid atomic decrement under lock if already rate-limited
  ratelimit: Avoid atomic decrement if already rate-limited
  ratelimit: Don't flush misses counter if RATELIMIT_MSG_ON_RELEASE
  ratelimit: Force re-initialization when rate-limiting re-enabled
  ratelimit: Allow zero ->burst to disable ratelimiting
  ratelimit: Reduce ___ratelimit() false-positive rate limiting
  ratelimit: Avoid jiffies=0 special case
  ratelimit: Count misses due to lock contention
  ratelimit: Convert the ->missed field to atomic_t
  drm/amd/pm: Avoid open-coded use of ratelimit_state structure's internals
  drm/i915: Avoid open-coded use of ratelimit_state structure's ->missed field
  random: Avoid open-coded use of ratelimit_state structure's ->missed field
  ratelimit: Create functions to handle ratelimit_state internals
2025-05-27 10:48:36 -07:00

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