| Message ID | 20230209153204.818774692@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | fold per-CPU vmstats remotely | expand |
On Thu, Feb 09, 2023 at 12:01:57PM -0300, Marcelo Tosatti wrote: > this_cpu_cmpxchg was modified to atomic version, which > can be more costly than non-atomic version. > > Switch users of this_cpu_cmpxchg to this_cpu_cmpxchg_local > (which preserves pre-non-atomic this_cpu_cmpxchg behaviour). > > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Yes afaict these are the only pieces that uses the helper besides vmstat udpates. Acked-by: Peter Xu <peterx@redhat.com>
Index: linux-vmstat-remote/kernel/fork.c =================================================================== --- linux-vmstat-remote.orig/kernel/fork.c +++ linux-vmstat-remote/kernel/fork.c @@ -203,7 +203,7 @@ static bool try_release_thread_stack_to_ unsigned int i; for (i = 0; i < NR_CACHED_STACKS; i++) { - if (this_cpu_cmpxchg(cached_stacks[i], NULL, vm) != NULL) + if (this_cpu_cmpxchg_local(cached_stacks[i], NULL, vm) != NULL) continue; return true; } Index: linux-vmstat-remote/kernel/scs.c =================================================================== --- linux-vmstat-remote.orig/kernel/scs.c +++ linux-vmstat-remote/kernel/scs.c @@ -79,7 +79,7 @@ void scs_free(void *s) */ for (i = 0; i < NR_CACHED_SCS; i++) - if (this_cpu_cmpxchg(scs_cache[i], 0, s) == NULL) + if (this_cpu_cmpxchg_local(scs_cache[i], 0, s) == NULL) return; kasan_unpoison_vmalloc(s, SCS_SIZE, KASAN_VMALLOC_PROT_NORMAL);
this_cpu_cmpxchg was modified to atomic version, which can be more costly than non-atomic version. Switch users of this_cpu_cmpxchg to this_cpu_cmpxchg_local (which preserves pre-non-atomic this_cpu_cmpxchg behaviour). Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>