+ cpumask-introduce-for_each_cpu_and_from.patch added to mm-nonmm-unstable branch

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The patch titled
     Subject: cpumask: introduce for_each_cpu_and_from()
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     cpumask-introduce-for_each_cpu_and_from.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/cpumask-introduce-for_each_cpu_and_from.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Yury Norov <yury.norov@xxxxxxxxx>
Subject: cpumask: introduce for_each_cpu_and_from()
Date: Thu, 28 Dec 2023 12:09:28 -0800

Patch series "lib/group_cpus: rework grp_spread_init_one() and make it
O(1)", v4.

grp_spread_init_one() implementation is sub-optimal because it traverses
bitmaps from the beginning, instead of picking from the previous
iteration.

Fix it and use find_bit API where appropriate.  While here, optimize
cpumasks allocation and drop unneeded cpumask_empty() call.


This patch (of 9):

Similarly to for_each_cpu_and(), introduce a for_each_cpu_and_from(),
which is handy when it's needed to traverse 2 cpumasks or bitmaps,
starting from a given position.

Link: https://lkml.kernel.org/r/20231228200936.2475595-1-yury.norov@xxxxxxxxx
Link: https://lkml.kernel.org/r/20231228200936.2475595-2-yury.norov@xxxxxxxxx
Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Ming Lei <ming.lei@xxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 include/linux/cpumask.h |   11 +++++++++++
 include/linux/find.h    |    3 +++
 2 files changed, 14 insertions(+)

--- a/include/linux/cpumask.h~cpumask-introduce-for_each_cpu_and_from
+++ a/include/linux/cpumask.h
@@ -333,6 +333,17 @@ unsigned int __pure cpumask_next_wrap(in
 	for_each_and_bit(cpu, cpumask_bits(mask1), cpumask_bits(mask2), small_cpumask_bits)
 
 /**
+ * for_each_cpu_and_from - iterate over every cpu in both masks starting from a given cpu
+ * @cpu: the (optionally unsigned) integer iterator
+ * @mask1: the first cpumask pointer
+ * @mask2: the second cpumask pointer
+ *
+ * After the loop, cpu is >= nr_cpu_ids.
+ */
+#define for_each_cpu_and_from(cpu, mask1, mask2)				\
+	for_each_and_bit_from(cpu, cpumask_bits(mask1), cpumask_bits(mask2), small_cpumask_bits)
+
+/**
  * for_each_cpu_andnot - iterate over every cpu present in one mask, excluding
  *			 those present in another.
  * @cpu: the (optionally unsigned) integer iterator
--- a/include/linux/find.h~cpumask-introduce-for_each_cpu_and_from
+++ a/include/linux/find.h
@@ -563,6 +563,9 @@ unsigned long find_next_bit_le(const voi
 	     (bit) = find_next_and_bit((addr1), (addr2), (size), (bit)), (bit) < (size);\
 	     (bit)++)
 
+#define for_each_and_bit_from(bit, addr1, addr2, size) \
+	for (; (bit) = find_next_and_bit((addr1), (addr2), (size), (bit)), (bit) < (size); (bit)++)
+
 #define for_each_andnot_bit(bit, addr1, addr2, size) \
 	for ((bit) = 0;									\
 	     (bit) = find_next_andnot_bit((addr1), (addr2), (size), (bit)), (bit) < (size);\
_

Patches currently in -mm which might be from yury.norov@xxxxxxxxx are

cpumask-introduce-for_each_cpu_and_from.patch
lib-group_cpus-optimize-inner-loop-in-grp_spread_init_one.patch
lib-group_cpus-relax-atomicity-requirement-in-grp_spread_init_one.patch
lib-group_cpus-optimize-outer-loop-in-grp_spread_init_one.patch
lib-group_cpus-dont-zero-cpumasks-in-group_cpus_evenly-on-allocation.patch
lib-group_cpus-drop-unneeded-cpumask_empty-call-in-__group_cpus_evenly.patch
cpumask-define-cleanup-function-for-cpumasks.patch
lib-group_cpus-rework-group_cpus_evenly.patch
lib-group_cpus-simplify-group_cpus_evenly-for-more.patch





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