The patch titled
Subject: convert this_cpu_cmpxchg users to this_cpu_cmpxchg_local
has been added to the -mm mm-unstable branch. Its filename is
convert-this_cpu_cmpxchg-users-to-this_cpu_cmpxchg_local.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/convert-this_cpu_cmpxchg-users-to-this_cpu_cmpxchg_local.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Subject: convert this_cpu_cmpxchg users to this_cpu_cmpxchg_local
Date: Fri, 03 Mar 2023 16:58:48 -0300
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).
Link: https://lkml.kernel.org/r/20230303195908.926950608@xxxxxxxxxx
Acked-by: Peter Xu <peterx@xxxxxxxxxx>
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Cc: Aaron Tomlin <atomlin@xxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Huacai Chen <chenhuacai@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: "Russell King (Oracle)" <linux@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/kernel/fork.c~convert-this_cpu_cmpxchg-users-to-this_cpu_cmpxchg_local
+++ a/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;
}
--- a/kernel/scs.c~convert-this_cpu_cmpxchg-users-to-this_cpu_cmpxchg_local
+++ a/kernel/scs.c
@@ -83,7 +83,7 @@ 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);
_
Patches currently in -mm which might be from mtosatti@xxxxxxxxxx are
mm-vmstat-remove-remote-node-draining.patch
this_cpu_cmpxchg-arm64-switch-this_cpu_cmpxchg-to-locked-add-_local-function.patch
this_cpu_cmpxchg-loongarch-switch-this_cpu_cmpxchg-to-locked-add-_local-function.patch
this_cpu_cmpxchg-s390-switch-this_cpu_cmpxchg-to-locked-add-_local-function.patch
this_cpu_cmpxchg-x86-switch-this_cpu_cmpxchg-to-locked-add-_local-function.patch
add-this_cpu_cmpxchg_local-and-asm-generic-definitions.patch
convert-this_cpu_cmpxchg-users-to-this_cpu_cmpxchg_local.patch
mm-vmstat-switch-counter-modification-to-cmpxchg.patch
mm-vmstat-use-xchg-in-cpu_vm_stats_fold.patch
mm-vmstat-switch-vmstat-shepherd-to-flush-per-cpu-counters-remotely.patch
mm-vmstat-refresh-stats-remotely-instead-of-via-work-item.patch
