2022-03-29 13:29:00

by 王擎

Subject: [PATCH 1/3] sched: topology: add input parameter for sched_domain_flags_f()

From: Wang Qing <[email protected]>

sched_domain_flags_f() are statically set now, but actually, we can get a lot
of necessary information based on the cpu_map. e.g. we can know whether its
cache is shared.

Allows custom extension without affecting current.

Signed-off-by: Wang Qing <[email protected]>
---
arch/powerpc/kernel/smp.c | 4 ++--
arch/x86/kernel/smpboot.c | 8 ++++----
include/linux/sched/topology.h | 10 +++++-----
kernel/sched/topology.c | 2 +-
4 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index de0f6f0..e503d23
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1000,7 +1000,7 @@ static bool shared_caches;

#ifdef CONFIG_SCHED_SMT
/* cpumask of CPUs with asymmetric SMT dependency */
-static int powerpc_smt_flags(void)
+static int powerpc_smt_flags(const struct cpumask *cpu_map)
{
int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;

@@ -1018,7 +1018,7 @@ static int powerpc_smt_flags(void)
* since the migrated task remains cache hot. We want to take advantage of this
* at the scheduler level so an extra topology level is required.
*/
-static int powerpc_shared_cache_flags(void)
+static int powerpc_shared_cache_flags(const struct cpumask *cpu_map)
{
return SD_SHARE_PKG_RESOURCES;
}
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 2ef1477..c005a8e
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -535,25 +535,25 @@ static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)


#if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_CLUSTER) || defined(CONFIG_SCHED_MC)
-static inline int x86_sched_itmt_flags(void)
+static inline int x86_sched_itmt_flags(const struct cpumask *cpu_map)
{
return sysctl_sched_itmt_enabled ? SD_ASYM_PACKING : 0;
}

#ifdef CONFIG_SCHED_MC
-static int x86_core_flags(void)
+static int x86_core_flags(const struct cpumask *cpu_map)
{
return cpu_core_flags() | x86_sched_itmt_flags();
}
#endif
#ifdef CONFIG_SCHED_SMT
-static int x86_smt_flags(void)
+static int x86_smt_flags(const struct cpumask *cpu_map)
{
return cpu_smt_flags() | x86_sched_itmt_flags();
}
#endif
#ifdef CONFIG_SCHED_CLUSTER
-static int x86_cluster_flags(void)
+static int x86_cluster_flags(const struct cpumask *cpu_map)
{
return cpu_cluster_flags() | x86_sched_itmt_flags();
}
diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index 56cffe4..6aa985a
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -36,28 +36,28 @@ extern const struct sd_flag_debug sd_flag_debug[];
#endif

#ifdef CONFIG_SCHED_SMT
-static inline int cpu_smt_flags(void)
+static inline int cpu_smt_flags(const struct cpumask *cpu_map)
{
return SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
}
#endif

#ifdef CONFIG_SCHED_CLUSTER
-static inline int cpu_cluster_flags(void)
+static inline int cpu_cluster_flags(const struct cpumask *cpu_map)
{
return SD_SHARE_PKG_RESOURCES;
}
#endif

#ifdef CONFIG_SCHED_MC
-static inline int cpu_core_flags(void)
+static inline int cpu_core_flags(const struct cpumask *cpu_map)
{
return SD_SHARE_PKG_RESOURCES;
}
#endif

#ifdef CONFIG_NUMA
-static inline int cpu_numa_flags(void)
+static inline int cpu_numa_flags(const struct cpumask *cpu_map)
{
return SD_NUMA;
}
@@ -180,7 +180,7 @@ void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms);
bool cpus_share_cache(int this_cpu, int that_cpu);

typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
-typedef int (*sched_domain_flags_f)(void);
+typedef int (*sched_domain_flags_f)(const struct cpumask *cpu_map);

#define SDTL_OVERLAP 0x01

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 05b6c2a..34dfec4
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1556,7 +1556,7 @@ sd_init(struct sched_domain_topology_level *tl,
sd_weight = cpumask_weight(tl->mask(cpu));

if (tl->sd_flags)
- sd_flags = (*tl->sd_flags)();
+ sd_flags = (*tl->sd_flags)(tl->mask(cpu));
if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS,
"wrong sd_flags in topology description\n"))
sd_flags &= TOPOLOGY_SD_FLAGS;
--
2.7.4

2022-03-29 22:29:49

by Peter Zijlstra

Subject: Re: [PATCH 1/3] sched: topology: add input parameter for sched_domain_flags_f()

On Tue, Mar 29, 2022 at 02:15:19AM -0700, Qing Wang wrote:
> From: Wang Qing <[email protected]>
>
> sched_domain_flags_f() are statically set now, but actually, we can get a lot
> of necessary information based on the cpu_map. e.g. we can know whether its
> cache is shared.
>
> Allows custom extension without affecting current.

Still NAK