On 11 October 2026 21:06:24 BST, Mathieu Desnoyers <[email protected]> wrote: >On 2026-10-11 15:59, Bradley Morgan wrote: >> On 11 October 2026 20:48:50 BST, Mathieu Desnoyers >> <[email protected]> wrote: >>> Introduce a "try acquire" hazard pointer fast path, which performs an >>> early load of the address to store it into the hazard pointer slot, and >>> then re-loads that address after a barrier to check whether it has >>> changed meanwhile. >>> >>> On comparison failure, rather than re-try, guarantee forward progress >by >>> falling back to the __hazptr_acquire slow path on failure. >>> >>> The acquire slow path attempts a try-acquire for any available per-CPU >>> slot. If that fails, it chains the backup slot into the overflow list, >>> therefore guaranteeing forward progress for both hazard pointer >>> read-side and synchronize: >>> >>> - Readers set the wildcard, and then proceed to set the more >>> specific address to replace the wildcard. >>> >>> - One synchronize alternates between two overflow list periods, >>> scanning each one while readers are added to the other period, >>> thus preventing a steady flow of readers from preventing >>> synchronize forward progress. >>> >>> With this change, the scan on per-CPU slots don't need to expect a >>> wildcard anymore, because none can be produced by readers. Wildcards >are >>> only expected within overflow lists. >>> >>> Signed-off-by: Mathieu Desnoyers <[email protected]> >>> Suggested-by: Gary Guo <[email protected]> >>> Link: >https://lore.kernel.org/lkmm/[email protected]/ >>> Reviewed-by: Gary Guo <[email protected]> >> >> Hi, my R-B still stands from >> >> >https://lore.kernel.org/all/[email protected]/ >> >> Reviewed-by: Bradley Morgan <[email protected]> > >Sorry, I forgot to add it to my commit message. I'll add it to the next >round (if there is one), else hopefully Paul can add the R-B tag if he >picks up this series. > >Thanks!
Thanks, this thing happens.. :) > >Mathieu > > > --- Thanks! "I'm not a very positive person" - Linus torvalds
