diff --git a/lib/libc/sys/_umtx_op.2 b/lib/libc/sys/_umtx_op.2 index f4a908b8501..93078a76549 100644 --- a/lib/libc/sys/_umtx_op.2 +++ b/lib/libc/sys/_umtx_op.2 @@ -1270,6 +1270,17 @@ in which case list processing is continued. See .Sx ROBUST UMUTEXES subsection for details. +.It Dv UMTX_OP_GET_MIN_TIMEOUT +Writes out the current value of minimal umtx operations timeout, +in nanoseconds, into the long integer variable pointed to by +.Fa uaddr1 . +.It Dv UMTX_OP_SET_MIN_TIMEOUT +Set the minimal amount of time, in nanoseconds, the thread is required +to sleep for umtx operations specifying a timeout using absolute clocks. +The value is taken from the +.Fa val +argument of the call. +Zero means no minimum. .El .Pp The diff --git a/lib/libthr/libthr.3 b/lib/libthr/libthr.3 index 3018a6f20b8..0477ac0647a 100644 --- a/lib/libthr/libthr.3 +++ b/lib/libthr/libthr.3 @@ -196,6 +196,12 @@ The integer value of the variable specifies how often blocked threads are inserted at the head of the sleep queue, instead of its tail. Bigger values reduce the frequency of the FIFO discipline. The value must be between 0 and 255. +.It Dv LIBPTHREAD_UMTX_MIN_TIMEOUT +The minimal amount of time, in nanoseconds, the thread is required to sleep +for pthread operations specifying a timeout. +If the operation requests a timeout less than the value provided, +it is silently increased to the value. +The value of zero means no minimum (default). .Pp .El The following diff --git a/lib/libthr/thread/thr_init.c b/lib/libthr/thread/thr_init.c index 1c4867cb818..6010dd4c045 100644 --- a/lib/libthr/thread/thr_init.c +++ b/lib/libthr/thread/thr_init.c @@ -522,6 +522,17 @@ init_private(void) if (env) _thr_queuefifo = atoi(env); TAILQ_INIT(&_thr_atfork_list); + env = getenv("LIBPTHREAD_UMTX_MIN_TIMEOUT"); + if (env) { + char *endptr; + long mint; + + mint = strtol(env, &endptr, 0); + if (*endptr == '\0' && mint >= 0) { + _umtx_op(NULL, UMTX_OP_SET_MIN_TIMEOUT, + mint, NULL, NULL); + } + } } init_once = 1; } diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c index ad54783dd4a..0e432d6978e 100644 --- a/sys/kern/kern_thread.c +++ b/sys/kern/kern_thread.c @@ -101,7 +101,7 @@ _Static_assert(offsetof(struct proc, p_filemon) == 0x3c8, "struct proc KBI p_filemon"); _Static_assert(offsetof(struct proc, p_comm) == 0x3e0, "struct proc KBI p_comm"); -_Static_assert(offsetof(struct proc, p_emuldata) == 0x4c8, +_Static_assert(offsetof(struct proc, p_emuldata) == 0x4d0, "struct proc KBI p_emuldata"); #endif #ifdef __i386__ @@ -121,7 +121,7 @@ _Static_assert(offsetof(struct proc, p_filemon) == 0x270, "struct proc KBI p_filemon"); _Static_assert(offsetof(struct proc, p_comm) == 0x284, "struct proc KBI p_comm"); -_Static_assert(offsetof(struct proc, p_emuldata) == 0x310, +_Static_assert(offsetof(struct proc, p_emuldata) == 0x318, "struct proc KBI p_emuldata"); #endif diff --git a/sys/kern/kern_umtx.c b/sys/kern/kern_umtx.c index 86d644c835c..92c7de6f2a2 100644 --- a/sys/kern/kern_umtx.c +++ b/sys/kern/kern_umtx.c @@ -700,6 +700,19 @@ umtx_abs_timeout_init2(struct umtx_abs_timeout *timo, (umtxtime->_flags & UMTX_ABSTIME) != 0, &umtxtime->_timeout); } +static void +umtx_abs_timeout_enforce_min(sbintime_t *sbt) +{ + sbintime_t when, mint; + + mint = curproc->p_umtx_min_timeout; + if (__predict_false(mint != 0)) { + when = sbinuptime() + mint; + if (*sbt < when) + *sbt = when; + } +} + static int umtx_abs_timeout_getsbt(struct umtx_abs_timeout *timo, sbintime_t *sbt, int *flags) @@ -739,6 +752,7 @@ umtx_abs_timeout_getsbt(struct umtx_abs_timeout *timo, sbintime_t *sbt, return (0); } *sbt = bttosbt(bt); + umtx_abs_timeout_enforce_min(sbt); /* * Check if the absolute time should be aligned to @@ -4594,6 +4608,33 @@ __umtx_op_robust_lists(struct thread *td, struct _umtx_op_args *uap, return (0); } +static int +__umtx_op_get_min_timeout(struct thread *td, struct _umtx_op_args *uap, + const struct umtx_copyops *ops) +{ + long val; + int error, val1; + + val = sbttons(td->td_proc->p_umtx_min_timeout); + if (ops->compat32) { + val1 = (int)val; + error = copyout(&val1, uap->uaddr1, sizeof(val1)); + } else { + error = copyout(&val, uap->uaddr1, sizeof(val)); + } + return (error); +} + +static int +__umtx_op_set_min_timeout(struct thread *td, struct _umtx_op_args *uap, + const struct umtx_copyops *ops) +{ + if (uap->val < 0) + return (EINVAL); + td->td_proc->p_umtx_min_timeout = nstosbt(uap->val); + return (0); +} + #if defined(__i386__) || defined(__amd64__) /* * Provide the standard 32-bit definitions for x86, since native/compat32 use a @@ -4816,6 +4857,8 @@ static const _umtx_op_func op_table[] = { [UMTX_OP_SEM2_WAKE] = __umtx_op_sem2_wake, [UMTX_OP_SHM] = __umtx_op_shm, [UMTX_OP_ROBUST_LISTS] = __umtx_op_robust_lists, + [UMTX_OP_GET_MIN_TIMEOUT] = __umtx_op_get_min_timeout, + [UMTX_OP_SET_MIN_TIMEOUT] = __umtx_op_set_min_timeout, }; static const struct umtx_copyops umtx_native_ops = { @@ -4990,6 +5033,8 @@ umtx_exec(struct proc *p) umtx_thread_cleanup(td); td->td_rb_list = td->td_rbp_list = td->td_rb_inact = 0; } + + p->p_umtx_min_timeout = 0; } /* diff --git a/sys/sys/proc.h b/sys/sys/proc.h index 172e716d878..1292315990b 100644 --- a/sys/sys/proc.h +++ b/sys/sys/proc.h @@ -741,6 +741,7 @@ struct proc { uint64_t p_elf_flags; /* (x) ELF flags */ void *p_elf_brandinfo; /* (x) Elf_Brandinfo, NULL for non ELF binaries. */ + sbintime_t p_umtx_min_timeout; /* End area that is copied on creation. */ #define p_endcopy p_xexit diff --git a/sys/sys/umtx.h b/sys/sys/umtx.h index 82a8e0e4b0f..ddd3bd38709 100644 --- a/sys/sys/umtx.h +++ b/sys/sys/umtx.h @@ -103,6 +103,8 @@ #define UMTX_OP_SEM2_WAKE 24 #define UMTX_OP_SHM 25 #define UMTX_OP_ROBUST_LISTS 26 +#define UMTX_OP_GET_MIN_TIMEOUT 27 +#define UMTX_OP_SET_MIN_TIMEOUT 28 /* * Flags for ops; the double-underbar convention must be maintained for future