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[24.1.27.177]) by smtp.gmail.com with ESMTPSA id z26-20020a056602005a00b007b6ed1d8884sm2412341ioz.39.2023.12.11.16.31.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Dec 2023 16:31:55 -0800 (PST) From: David Vernet To: linux-kernel@vger.kernel.org Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, youssefesmat@google.com, joelaf@google.com, roman.gushchin@linux.dev, yu.c.chen@intel.com, kprateek.nayak@amd.com, gautham.shenoy@amd.com, aboorvad@linux.vnet.ibm.com, wuyun.abel@bytedance.com, tj@kernel.org, kernel-team@meta.com Subject: [PATCH v4 5/8] sched: Enable sched_feat callbacks on enable/disable Date: Mon, 11 Dec 2023 18:31:38 -0600 Message-ID: <20231212003141.216236-6-void@manifault.com> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231212003141.216236-1-void@manifault.com> References: <20231212003141.216236-1-void@manifault.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When a scheduler feature is enabled or disabled, the sched_feat_enable() and sched_feat_disable() functions are invoked respectively for that feature. For features that don't require resetting any state, this works fine. However, there will be an upcoming feature called SHARED_RUNQ which needs to drain all tasks from a set of global shared runqueues in order to avoid stale tasks from staying in the queues after the feature has been disabled. This patch therefore defines a new SCHED_FEAT_CALLBACK macro which allows scheduler features to specify a callback that should be invoked when a feature is enabled or disabled respectively. The SCHED_FEAT macro assumes a NULL callback. Signed-off-by: David Vernet --- kernel/sched/core.c | 4 ++-- kernel/sched/debug.c | 18 ++++++++++++++---- kernel/sched/sched.h | 16 ++++++++++------ 3 files changed, 26 insertions(+), 12 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 9ad7f0255e14..045ac2539f37 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -124,12 +124,12 @@ DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); * sysctl_sched_features, defined in sched.h, to allow constants propagati= on * at compile time and compiler optimization based on features default. */ -#define SCHED_FEAT(name, enabled) \ +#define SCHED_FEAT_CALLBACK(name, enabled, cb) \ (1UL << __SCHED_FEAT_##name) * enabled | const_debug unsigned int sysctl_sched_features =3D #include "features.h" 0; -#undef SCHED_FEAT +#undef SCHED_FEAT_CALLBACK =20 /* * Print a warning if need_resched is set for the given duration (if diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 168eecc209b4..0b72799c7e84 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -44,14 +44,14 @@ static unsigned long nsec_low(unsigned long long nsec) =20 #define SPLIT_NS(x) nsec_high(x), nsec_low(x) =20 -#define SCHED_FEAT(name, enabled) \ +#define SCHED_FEAT_CALLBACK(name, enabled, cb) \ #name , =20 static const char * const sched_feat_names[] =3D { #include "features.h" }; =20 -#undef SCHED_FEAT +#undef SCHED_FEAT_CALLBACK =20 static int sched_feat_show(struct seq_file *m, void *v) { @@ -72,22 +72,32 @@ static int sched_feat_show(struct seq_file *m, void *v) #define jump_label_key__true STATIC_KEY_INIT_TRUE #define jump_label_key__false STATIC_KEY_INIT_FALSE =20 -#define SCHED_FEAT(name, enabled) \ +#define SCHED_FEAT_CALLBACK(name, enabled, cb) \ jump_label_key__##enabled , =20 struct static_key sched_feat_keys[__SCHED_FEAT_NR] =3D { #include "features.h" }; =20 -#undef SCHED_FEAT +#undef SCHED_FEAT_CALLBACK + +#define SCHED_FEAT_CALLBACK(name, enabled, cb) cb, +static const sched_feat_change_f sched_feat_cbs[__SCHED_FEAT_NR] =3D { +#include "features.h" +}; +#undef SCHED_FEAT_CALLBACK =20 static void sched_feat_disable(int i) { + if (sched_feat_cbs[i]) + sched_feat_cbs[i](false); static_key_disable_cpuslocked(&sched_feat_keys[i]); } =20 static void sched_feat_enable(int i) { + if (sched_feat_cbs[i]) + sched_feat_cbs[i](true); static_key_enable_cpuslocked(&sched_feat_keys[i]); } #else diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 53fe2294eec7..517e67a0cc9a 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2091,6 +2091,8 @@ static inline void __set_task_cpu(struct task_struct = *p, unsigned int cpu) #endif } =20 +#define SCHED_FEAT(name, enabled) SCHED_FEAT_CALLBACK(name, enabled, NULL) + /* * Tunables that become constants when CONFIG_SCHED_DEBUG is off: */ @@ -2100,7 +2102,7 @@ static inline void __set_task_cpu(struct task_struct = *p, unsigned int cpu) # define const_debug const #endif =20 -#define SCHED_FEAT(name, enabled) \ +#define SCHED_FEAT_CALLBACK(name, enabled, cb) \ __SCHED_FEAT_##name , =20 enum { @@ -2108,7 +2110,7 @@ enum { __SCHED_FEAT_NR, }; =20 -#undef SCHED_FEAT +#undef SCHED_FEAT_CALLBACK =20 #ifdef CONFIG_SCHED_DEBUG =20 @@ -2119,14 +2121,14 @@ enum { extern const_debug unsigned int sysctl_sched_features; =20 #ifdef CONFIG_JUMP_LABEL -#define SCHED_FEAT(name, enabled) \ +#define SCHED_FEAT_CALLBACK(name, enabled, cb) \ static __always_inline bool static_branch_##name(struct static_key *key) \ { \ return static_key_##enabled(key); \ } =20 #include "features.h" -#undef SCHED_FEAT +#undef SCHED_FEAT_CALLBACK =20 extern struct static_key sched_feat_keys[__SCHED_FEAT_NR]; #define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x= ])) @@ -2144,17 +2146,19 @@ extern struct static_key sched_feat_keys[__SCHED_FE= AT_NR]; * constants propagation at compile time and compiler optimization based on * features default. */ -#define SCHED_FEAT(name, enabled) \ +#define SCHED_FEAT_CALLBACK(name, enabled, cb) \ (1UL << __SCHED_FEAT_##name) * enabled | static const_debug __maybe_unused unsigned int sysctl_sched_features =3D #include "features.h" 0; -#undef SCHED_FEAT +#undef SCHED_FEAT_CALLBACK =20 #define sched_feat(x) !!(sysctl_sched_features & (1UL << __SCHED_FEAT_##x)) =20 #endif /* SCHED_DEBUG */ =20 +typedef void (*sched_feat_change_f)(bool enabling); + extern struct static_key_false sched_numa_balancing; extern struct static_key_false sched_schedstats; =20 --=20 2.42.1