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Message-Id: <20200815031908.1015049-9-joel@joelfernandes.org>
Date: Fri, 14 Aug 2020 23:19:04 -0400
From: "Joel Fernandes (Google)" <joel@...lfernandes.org>
To: linux-kernel@...r.kernel.org
Cc: Vineeth Pillai <viremana@...ux.microsoft.com>,
Joel Fernandes <joel@...lfernandes.org>,
Aaron Lu <aaron.lwe@...il.com>,
Aubrey Li <aubrey.li@...ux.intel.com>,
Julien Desfossez <jdesfossez@...italocean.com>,
Kees Cook <keescook@...omium.org>,
"Paul E. McKenney" <paulmck@...nel.org>,
Paul Turner <pjt@...gle.com>,
Peter Zijlstra <peterz@...radead.org>,
Steven Rostedt <rostedt@...dmis.org>,
Thomas Gleixner <tglx@...utronix.de>,
Tim Chen <tim.c.chen@...el.com>,
Tim Chen <tim.c.chen@...ux.intel.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
fweisbec@...il.com, kerrnel@...gle.com,
Phil Auld <pauld@...hat.com>,
Valentin Schneider <valentin.schneider@....com>,
Paolo Bonzini <pbonzini@...hat.com>,
Chen Yu <yu.c.chen@...el.com>,
Christian Brauner <christian.brauner@...ntu.com>
Subject: [PATCH RFC 08/12] cpumask: Introduce a new iterator for_each_cpu_wrap_or
From: Vineeth Pillai <viremana@...ux.microsoft.com>
Hotplug fixes to core-scheduling require a new cpumask iterator which iterates
through all online cpus in both the given cpumasks. This patch introduces it.
Signed-off-by: Vineeth Pillai <viremana@...ux.microsoft.com>
Signed-off-by: Joel Fernandes (Google) <joel@...lfernandes.org>
---
include/linux/cpumask.h | 42 ++++++++++++++++++++++++++++++++
lib/cpumask.c | 53 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 95 insertions(+)
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index f0d895d6ac39..03e8c57c6ca6 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -207,6 +207,10 @@ static inline int cpumask_any_and_distribute(const struct cpumask *src1p,
for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask, (void)(start))
#define for_each_cpu_and(cpu, mask1, mask2) \
for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask1, (void)mask2)
+#define for_each_cpu_or(cpu, mask1, mask2) \
+ for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask1, (void)mask2)
+#define for_each_cpu_wrap_or(cpu, mask1, mask2, start) \
+ for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask1, (void)mask2, (void)(start))
#else
/**
* cpumask_first - get the first cpu in a cpumask
@@ -248,6 +252,7 @@ static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp)
}
int cpumask_next_and(int n, const struct cpumask *, const struct cpumask *);
+int cpumask_next_or(int n, const struct cpumask *, const struct cpumask *);
int cpumask_any_but(const struct cpumask *mask, unsigned int cpu);
unsigned int cpumask_local_spread(unsigned int i, int node);
int cpumask_any_and_distribute(const struct cpumask *src1p,
@@ -278,6 +283,8 @@ int cpumask_any_and_distribute(const struct cpumask *src1p,
(cpu) < nr_cpu_ids;)
extern int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap);
+extern int cpumask_next_wrap_or(int n, const struct cpumask *mask1,
+ const struct cpumask *mask2, int start, bool wrap);
/**
* for_each_cpu_wrap - iterate over every cpu in a mask, starting at a specified location
@@ -294,6 +301,22 @@ extern int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool
(cpu) < nr_cpumask_bits; \
(cpu) = cpumask_next_wrap((cpu), (mask), (start), true))
+/**
+ * for_each_cpu_wrap_or - iterate over every cpu in both masks, starting at a specified location
+ * @cpu: the (optionally unsigned) integer iterator
+ * @mask1: the first cpumask pointer
+ * @mask2: the second cpumask pointer
+ * @start: the start location
+ *
+ * The implementation does not assume any bit both masks are set (including @start).
+ *
+ * After the loop, cpu is >= nr_cpu_ids.
+ */
+#define for_each_cpu_wrap_or(cpu, mask1, mask2, start) \
+ for ((cpu) = cpumask_next_wrap_or((start)-1, (mask1), (mask2), (start), false); \
+ (cpu) < nr_cpumask_bits; \
+ (cpu) = cpumask_next_wrap_or((cpu), (mask1), (mask2), (start), true))
+
/**
* for_each_cpu_and - iterate over every cpu in both masks
* @cpu: the (optionally unsigned) integer iterator
@@ -312,6 +335,25 @@ extern int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool
for ((cpu) = -1; \
(cpu) = cpumask_next_and((cpu), (mask1), (mask2)), \
(cpu) < nr_cpu_ids;)
+
+/**
+ * for_each_cpu_or - iterate over every cpu in both masks
+ * @cpu: the (optionally unsigned) integer iterator
+ * @mask1: the first cpumask pointer
+ * @mask2: the second cpumask pointer
+ *
+ * This saves a temporary CPU mask in many places. It is equivalent to:
+ * struct cpumask tmp;
+ * cpumask_and(&tmp, &mask1, &mask2);
+ * for_each_cpu(cpu, &tmp)
+ * ...
+ *
+ * After the loop, cpu is >= nr_cpu_ids.
+ */
+#define for_each_cpu_or(cpu, mask1, mask2) \
+ for ((cpu) = -1; \
+ (cpu) = cpumask_next_or((cpu), (mask1), (mask2)), \
+ (cpu) < nr_cpu_ids;)
#endif /* SMP */
#define CPU_BITS_NONE \
diff --git a/lib/cpumask.c b/lib/cpumask.c
index fb22fb266f93..0a5cdbd4eb6a 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -42,6 +42,25 @@ int cpumask_next_and(int n, const struct cpumask *src1p,
}
EXPORT_SYMBOL(cpumask_next_and);
+/**
+ * cpumask_next_or - get the next cpu in *src1p | *src2p
+ * @n: the cpu prior to the place to search (ie. return will be > @n)
+ * @src1p: the first cpumask pointer
+ * @src2p: the second cpumask pointer
+ *
+ * Returns >= nr_cpu_ids if no further cpus set in both.
+ */
+int cpumask_next_or(int n, const struct cpumask *src1p,
+ const struct cpumask *src2p)
+{
+ /* -1 is a legal arg here. */
+ if (n != -1)
+ cpumask_check(n);
+ return find_next_or_bit(cpumask_bits(src1p), cpumask_bits(src2p),
+ nr_cpumask_bits, n + 1);
+}
+EXPORT_SYMBOL(cpumask_next_or);
+
/**
* cpumask_any_but - return a "random" in a cpumask, but not this one.
* @mask: the cpumask to search
@@ -94,6 +113,40 @@ int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap)
}
EXPORT_SYMBOL(cpumask_next_wrap);
+/**
+ * cpumask_next_wrap_or - helper to implement for_each_cpu_wrap_or
+ * @n: the cpu prior to the place to search
+ * @mask1: first cpumask pointer
+ * @mask2: second cpumask pointer
+ * @start: the start point of the iteration
+ * @wrap: assume @n crossing @start terminates the iteration
+ *
+ * Returns >= nr_cpu_ids on completion
+ *
+ * Note: the @wrap argument is required for the start condition when
+ * we cannot assume @start is set in @mask.
+ */
+int cpumask_next_wrap_or(int n, const struct cpumask *mask1, const struct cpumask *mask2,
+ int start, bool wrap)
+{
+ int next;
+
+again:
+ next = cpumask_next_or(n, mask1, mask2);
+
+ if (wrap && n < start && next >= start) {
+ return nr_cpumask_bits;
+
+ } else if (next >= nr_cpumask_bits) {
+ wrap = true;
+ n = -1;
+ goto again;
+ }
+
+ return next;
+}
+EXPORT_SYMBOL(cpumask_next_wrap_or);
+
/* These are not inline because of header tangles. */
#ifdef CONFIG_CPUMASK_OFFSTACK
/**
--
2.28.0.220.ged08abb693-goog
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