[lkml]   [2021]   [Jul]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [GIT PULL] sigqueue cache fix

On Mon, Jun 28 2021 at 12:02, Linus Torvalds wrote:
> And as the whole - and only - point of the sigqueue cache was a very
> subtle performance and latency issue, I don't think we want to use
> locks or atomics. It's why my revert commit suggests re-purposing the
> "percpu_cmpxchg()" functionality: that would likely be a good model at
> least for x86 and arm.
> But while we have "percpu_cmpxchg()", I don't think we currently don't
> really have that kind of operation where it
> (a) works on a non-percpu variable (but we can force casts, I guess)
> (b) has "acquire" semantics
> We do have the *atomic* cmpxchg with acquire semantics, but atomics
> are rather more expensive than we'd probably really want.

first of all, sorry for being non-responsive on this. I'll have a fresh
look at this with your comments in mind and be more careful.



 \ /
  Last update: 2021-07-07 11:48    [W:0.054 / U:0.256 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site