+ convert-this_cpu_cmpxchg-users-to-this_cpu_cmpxchg_local.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

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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@redhat.com>
Subject: convert this_cpu_cmpxchg users to this_cpu_cmpxchg_local
Date: Mon, 13 Mar 2023 13:25:13 -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/20230313162634.408562151@redhat.com
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---


--- 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@redhat.com are

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
vmstat-switch-per-cpu-vmstat-counters-to-32-bits.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
vmstat-add-pcp-remote-node-draining-via-cpu_vm_stats_fold.patch