Date: Fri, 11 Dec 2020 20:01:45 +0000 (UTC) From: Mitchell Horne <mhorne@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r368558 - head/sys/riscv/include Message-ID: <202012112001.0BBK1jJU021350@repo.freebsd.org>
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Author: mhorne Date: Fri Dec 11 20:01:45 2020 New Revision: 368558 URL: https://svnweb.freebsd.org/changeset/base/368558 Log: riscv: small counter(9) improvements Prefer atomics to critical section. This reduces the cost of the increment operation and removes the possibility of it being interrupted by counter_u64_zero(). Use CPU_FOREACH() macro to skip absent CPUs. Replace hand-rolled address calculation with zpcpu_get(). Reviewed by: markj Differential Revision: https://reviews.freebsd.org/D27536 Modified: head/sys/riscv/include/counter.h Modified: head/sys/riscv/include/counter.h ============================================================================== --- head/sys/riscv/include/counter.h Fri Dec 11 19:45:40 2020 (r368557) +++ head/sys/riscv/include/counter.h Fri Dec 11 20:01:45 2020 (r368558) @@ -30,14 +30,12 @@ #define _MACHINE_COUNTER_H_ #include <sys/pcpu.h> -#ifdef INVARIANTS -#include <sys/proc.h> -#endif +#include <machine/atomic.h> #define EARLY_COUNTER &__pcpu[0].pc_early_dummy_counter -#define counter_enter() critical_enter() -#define counter_exit() critical_exit() +#define counter_enter() do {} while (0) +#define counter_exit() do {} while (0) #ifdef IN_SUBR_COUNTER_C static inline uint64_t @@ -54,19 +52,17 @@ counter_u64_fetch_inline(uint64_t *p) int i; r = 0; - for (i = 0; i < mp_ncpus; i++) - r += counter_u64_read_one((uint64_t *)p, i); + CPU_FOREACH(i) + r += counter_u64_read_one(p, i); return (r); } -/* XXXKIB might interrupt increment */ static void counter_u64_zero_one_cpu(void *arg) { - *((uint64_t *)((char *)arg + UMA_PCPU_ALLOC_SIZE * - PCPU_GET(cpuid))) = 0; + *(zpcpu_get((counter_u64_t *)arg)) = 0; } static inline void @@ -78,18 +74,13 @@ counter_u64_zero_inline(counter_u64_t c) } #endif -#define counter_u64_add_protected(c, inc) do { \ - CRITICAL_ASSERT(curthread); \ - *(uint64_t *)zpcpu_get(c) += (inc); \ -} while (0) +#define counter_u64_add_protected(c, inc) counter_u64_add(c, inc) static inline void counter_u64_add(counter_u64_t c, int64_t inc) { - counter_enter(); - counter_u64_add_protected(c, inc); - counter_exit(); + atomic_add_64((uint64_t *)zpcpu_get(c), inc); } #endif /* ! _MACHINE_COUNTER_H_ */
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