From: Changwoo Min Date: Sun, 9 Feb 2025 01:53:53 +0000 (+0900) Subject: tools/sched_ext: Compatible testing of SCX_ENQ_CPU_SELECTED X-Git-Tag: v6.15-rc1~227^2~26 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=372033ad9e98dce205fc3c48a146cfff5699e3e9;p=thirdparty%2Fkernel%2Fstable.git tools/sched_ext: Compatible testing of SCX_ENQ_CPU_SELECTED This provides compatible testing of SCX_ENQ_CPU_SELECTED. More specifically, it handles two cases: 1. a BPF scheduler is compiled against vmlinux.h where SCX_ENQ_CPU_SELECTED is defined, but it runs on a kernel that does not have SCX_ENQ_CPU_SELECTED. In this case, the test result of 'enq_flags & SCX_ENQ_CPU_SELECTED' will always be false. That test result is semantically incorrect because the kernel before SCX_ENQ_CPU_SELECTED has never skipped select_task_rq_scx(), so the result should be true. 2. a BPF scheduler is compiling against vmlinux.h where SCX_ENQ_CPU_SELECTED is not defined. In this case, directly using SCX_ENQ_CPU_SELECTED causes compilation errors. To hide such complexity, introduce __COMPAT_is_enq_cpu_selected(), which checks if SCX_ENQ_CPU_SELECTED exists in runtime using BPF CO-RE. This consists of three parts: 1. Add enum_defs.autogen.h, which has macros (HAVE_{enum name}) denoting whether SCX enums are defined in the vmlinux.h or not. 2. Implement __COMPAT_is_enq_cpu_selected(), which provide the test of SCX_ENQ_CPU_SELECTED in a compatible way. 3. Use __COMPAT_is_enq_cpu_selected() in scx_qmap. Note that this is a sync of the relevant PR [1] in the scx repo. [1] https://github.com/sched-ext/scx/pull/1314 Signed-off-by: Changwoo Min Signed-off-by: Tejun Heo --- diff --git a/tools/sched_ext/include/scx/common.bpf.h b/tools/sched_ext/include/scx/common.bpf.h index ae717f4d6ede1..f1caf9fc8f8cc 100644 --- a/tools/sched_ext/include/scx/common.bpf.h +++ b/tools/sched_ext/include/scx/common.bpf.h @@ -18,6 +18,7 @@ #include #include #include "user_exit_info.h" +#include "enum_defs.autogen.h" #define PF_WQ_WORKER 0x00000020 /* I'm a workqueue worker */ #define PF_KTHREAD 0x00200000 /* I am a kernel thread */ diff --git a/tools/sched_ext/include/scx/common.h b/tools/sched_ext/include/scx/common.h index dc18b99e55cd1..1dc76bd842966 100644 --- a/tools/sched_ext/include/scx/common.h +++ b/tools/sched_ext/include/scx/common.h @@ -16,6 +16,7 @@ #include #include #include +#include "enum_defs.autogen.h" typedef uint8_t u8; typedef uint16_t u16; diff --git a/tools/sched_ext/include/scx/compat.bpf.h b/tools/sched_ext/include/scx/compat.bpf.h index 50e1499ae0935..e5fa72f9bf22b 100644 --- a/tools/sched_ext/include/scx/compat.bpf.h +++ b/tools/sched_ext/include/scx/compat.bpf.h @@ -125,6 +125,58 @@ bool scx_bpf_dispatch_vtime_from_dsq___compat(struct bpf_iter_scx_dsq *it__iter, false; \ }) +/** + * __COMPAT_is_enq_cpu_selected - Test if SCX_ENQ_CPU_SELECTED is on + * in a compatible way. We will preserve this __COMPAT helper until v6.16. + * + * @enq_flags: enqueue flags from ops.enqueue() + * + * Return: True if SCX_ENQ_CPU_SELECTED is turned on in @enq_flags + */ +static inline bool __COMPAT_is_enq_cpu_selected(u64 enq_flags) +{ +#ifdef HAVE_SCX_ENQ_CPU_SELECTED + /* + * This is the case that a BPF code compiled against vmlinux.h + * where the enum SCX_ENQ_CPU_SELECTED exists. + */ + + /* + * We should temporarily suspend the macro expansion of + * 'SCX_ENQ_CPU_SELECTED'. This avoids 'SCX_ENQ_CPU_SELECTED' being + * rewritten to '__SCX_ENQ_CPU_SELECTED' when 'SCX_ENQ_CPU_SELECTED' + * is defined in 'scripts/gen_enums.py'. + */ +#pragma push_macro("SCX_ENQ_CPU_SELECTED") +#undef SCX_ENQ_CPU_SELECTED + u64 flag; + + /* + * When the kernel did not have SCX_ENQ_CPU_SELECTED, + * select_task_rq_scx() has never been skipped. Thus, this case + * should be considered that the CPU has already been selected. + */ + if (!bpf_core_enum_value_exists(enum scx_enq_flags, + SCX_ENQ_CPU_SELECTED)) + return true; + + flag = bpf_core_enum_value(enum scx_enq_flags, SCX_ENQ_CPU_SELECTED); + return enq_flags & flag; + + /* + * Once done, resume the macro expansion of 'SCX_ENQ_CPU_SELECTED'. + */ +#pragma pop_macro("SCX_ENQ_CPU_SELECTED") +#else + /* + * This is the case that a BPF code compiled against vmlinux.h + * where the enum SCX_ENQ_CPU_SELECTED does NOT exist. + */ + return true; +#endif /* HAVE_SCX_ENQ_CPU_SELECTED */ +} + + #define scx_bpf_now() \ (bpf_ksym_exists(scx_bpf_now) ? \ scx_bpf_now() : \ diff --git a/tools/sched_ext/include/scx/enum_defs.autogen.h b/tools/sched_ext/include/scx/enum_defs.autogen.h new file mode 100644 index 0000000000000..5551816856ee7 --- /dev/null +++ b/tools/sched_ext/include/scx/enum_defs.autogen.h @@ -0,0 +1,119 @@ +/* + * WARNING: This file is autogenerated from scripts/gen_enum_defs.py. + */ + +#ifndef __ENUM_DEFS_AUTOGEN_H__ +#define __ENUM_DEFS_AUTOGEN_H__ + + +#define HAVE_SCX_DSP_DFL_MAX_BATCH +#define HAVE_SCX_DSP_MAX_LOOPS +#define HAVE_SCX_WATCHDOG_MAX_TIMEOUT +#define HAVE_SCX_EXIT_BT_LEN +#define HAVE_SCX_EXIT_MSG_LEN +#define HAVE_SCX_EXIT_DUMP_DFL_LEN +#define HAVE_SCX_CPUPERF_ONE +#define HAVE_SCX_OPS_TASK_ITER_BATCH +#define HAVE_SCX_CPU_PREEMPT_RT +#define HAVE_SCX_CPU_PREEMPT_DL +#define HAVE_SCX_CPU_PREEMPT_STOP +#define HAVE_SCX_CPU_PREEMPT_UNKNOWN +#define HAVE_SCX_DEQ_SLEEP +#define HAVE_SCX_DEQ_CORE_SCHED_EXEC +#define HAVE_SCX_DSQ_FLAG_BUILTIN +#define HAVE_SCX_DSQ_FLAG_LOCAL_ON +#define HAVE_SCX_DSQ_INVALID +#define HAVE_SCX_DSQ_GLOBAL +#define HAVE_SCX_DSQ_LOCAL +#define HAVE_SCX_DSQ_LOCAL_ON +#define HAVE_SCX_DSQ_LOCAL_CPU_MASK +#define HAVE_SCX_DSQ_ITER_REV +#define HAVE___SCX_DSQ_ITER_HAS_SLICE +#define HAVE___SCX_DSQ_ITER_HAS_VTIME +#define HAVE___SCX_DSQ_ITER_USER_FLAGS +#define HAVE___SCX_DSQ_ITER_ALL_FLAGS +#define HAVE_SCX_DSQ_LNODE_ITER_CURSOR +#define HAVE___SCX_DSQ_LNODE_PRIV_SHIFT +#define HAVE_SCX_ENQ_WAKEUP +#define HAVE_SCX_ENQ_HEAD +#define HAVE_SCX_ENQ_CPU_SELECTED +#define HAVE_SCX_ENQ_PREEMPT +#define HAVE_SCX_ENQ_REENQ +#define HAVE_SCX_ENQ_LAST +#define HAVE___SCX_ENQ_INTERNAL_MASK +#define HAVE_SCX_ENQ_CLEAR_OPSS +#define HAVE_SCX_ENQ_DSQ_PRIQ +#define HAVE_SCX_TASK_DSQ_ON_PRIQ +#define HAVE_SCX_TASK_QUEUED +#define HAVE_SCX_TASK_RESET_RUNNABLE_AT +#define HAVE_SCX_TASK_DEQD_FOR_SLEEP +#define HAVE_SCX_TASK_STATE_SHIFT +#define HAVE_SCX_TASK_STATE_BITS +#define HAVE_SCX_TASK_STATE_MASK +#define HAVE_SCX_TASK_CURSOR +#define HAVE_SCX_ECODE_RSN_HOTPLUG +#define HAVE_SCX_ECODE_ACT_RESTART +#define HAVE_SCX_EXIT_NONE +#define HAVE_SCX_EXIT_DONE +#define HAVE_SCX_EXIT_UNREG +#define HAVE_SCX_EXIT_UNREG_BPF +#define HAVE_SCX_EXIT_UNREG_KERN +#define HAVE_SCX_EXIT_SYSRQ +#define HAVE_SCX_EXIT_ERROR +#define HAVE_SCX_EXIT_ERROR_BPF +#define HAVE_SCX_EXIT_ERROR_STALL +#define HAVE_SCX_KF_UNLOCKED +#define HAVE_SCX_KF_CPU_RELEASE +#define HAVE_SCX_KF_DISPATCH +#define HAVE_SCX_KF_ENQUEUE +#define HAVE_SCX_KF_SELECT_CPU +#define HAVE_SCX_KF_REST +#define HAVE___SCX_KF_RQ_LOCKED +#define HAVE___SCX_KF_TERMINAL +#define HAVE_SCX_KICK_IDLE +#define HAVE_SCX_KICK_PREEMPT +#define HAVE_SCX_KICK_WAIT +#define HAVE_SCX_OPI_BEGIN +#define HAVE_SCX_OPI_NORMAL_BEGIN +#define HAVE_SCX_OPI_NORMAL_END +#define HAVE_SCX_OPI_CPU_HOTPLUG_BEGIN +#define HAVE_SCX_OPI_CPU_HOTPLUG_END +#define HAVE_SCX_OPI_END +#define HAVE_SCX_OPS_ENABLING +#define HAVE_SCX_OPS_ENABLED +#define HAVE_SCX_OPS_DISABLING +#define HAVE_SCX_OPS_DISABLED +#define HAVE_SCX_OPS_KEEP_BUILTIN_IDLE +#define HAVE_SCX_OPS_ENQ_LAST +#define HAVE_SCX_OPS_ENQ_EXITING +#define HAVE_SCX_OPS_SWITCH_PARTIAL +#define HAVE_SCX_OPS_HAS_CGROUP_WEIGHT +#define HAVE_SCX_OPS_ALL_FLAGS +#define HAVE_SCX_OPSS_NONE +#define HAVE_SCX_OPSS_QUEUEING +#define HAVE_SCX_OPSS_QUEUED +#define HAVE_SCX_OPSS_DISPATCHING +#define HAVE_SCX_OPSS_QSEQ_SHIFT +#define HAVE_SCX_PICK_IDLE_CORE +#define HAVE_SCX_OPS_NAME_LEN +#define HAVE_SCX_SLICE_DFL +#define HAVE_SCX_SLICE_INF +#define HAVE_SCX_RQ_ONLINE +#define HAVE_SCX_RQ_CAN_STOP_TICK +#define HAVE_SCX_RQ_BAL_PENDING +#define HAVE_SCX_RQ_BAL_KEEP +#define HAVE_SCX_RQ_BYPASSING +#define HAVE_SCX_RQ_IN_WAKEUP +#define HAVE_SCX_RQ_IN_BALANCE +#define HAVE_SCX_TASK_NONE +#define HAVE_SCX_TASK_INIT +#define HAVE_SCX_TASK_READY +#define HAVE_SCX_TASK_ENABLED +#define HAVE_SCX_TASK_NR_STATES +#define HAVE_SCX_TG_ONLINE +#define HAVE_SCX_TG_INITED +#define HAVE_SCX_WAKE_FORK +#define HAVE_SCX_WAKE_TTWU +#define HAVE_SCX_WAKE_SYNC + +#endif /* __ENUM_DEFS_AUTOGEN_H__ */ diff --git a/tools/sched_ext/scx_qmap.bpf.c b/tools/sched_ext/scx_qmap.bpf.c index e0e766d402e1c..a6c6be308315a 100644 --- a/tools/sched_ext/scx_qmap.bpf.c +++ b/tools/sched_ext/scx_qmap.bpf.c @@ -231,7 +231,7 @@ void BPF_STRUCT_OPS(qmap_enqueue, struct task_struct *p, u64 enq_flags) } /* if select_cpu() wasn't called, try direct dispatch */ - if (!(enq_flags & SCX_ENQ_CPU_SELECTED) && + if (!__COMPAT_is_enq_cpu_selected(enq_flags) && (cpu = pick_direct_dispatch_cpu(p, scx_bpf_task_cpu(p))) >= 0) { __sync_fetch_and_add(&nr_ddsp_from_enq, 1); scx_bpf_dsq_insert(p, SCX_DSQ_LOCAL_ON | cpu, slice_ns, enq_flags);