From 22098763a10d9c1340827fcf6edab66f153b27f0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 13 Sep 2026 12:27:00 -0700 Subject: Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Don't destroy user event fields when removal fails User event fields are destroyed before the event is removed from visibility. But that can fail leaving the still visible event with no fields. Move the destroying of the fields to after the event is successfully removed from visibility. - Initialize function graph state is fork before calling copy_exec_state() For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state. If that allocation fails, ftrace_graph_exit_task() will free the tasks ret_stack pointer. Since that pointer is still using the parent's ret_stack, it mistakenly frees the parent's pointer too. Call ftrace_graph_init() on the task first which will NULL out the new tasks's ret_stack and if the copy fails, it will not free anything. - Remove FGRAPH_MAX_INDEX The macro FGRAPH_MAX_INDEX was added but never used. Remove it. - Save ent_size in function graph printing of nested functions The function graph tracer needs to look at the next event to see if the next event is the return of the current function entry. If it is, it prints a single line: ktime_get(); Otherwise it prints it like a nested function: tick_nohz_irq_exit() { ktime_get(); kcpustat_irq_exit(); } In order to look at the next event, it must save the current event so that it has the information to print from it. It saves the event in the iterator descriptor called "ent". What it doesn't save is the ent_size of the event which is now used to know if the function graph arguments are to be printed. The peek doesn't save the size so the size used happens to be that of the size of the last event that was seen. Save the entry event size in the iterator descriptor so that the correct size is used. - Fix several errors with freeing data in the histogram code The histogram code had a lot of leaked or or incorrect accounting when failures happen. Correct them. - Fix histogram regression of .percent and .graph modifiers Up until 6.3 histogram values could have "percent" or "graph" modifiers that changed how they were printed. But a change that added restricting histograms values from being strings, stack traces and other modifiers inadvertently prevented them from using the percent and graph modifiers, which were legal use cases for values. Put back the percent and graph modifiers. - Fix various typos in the comments - Set the trace_clock before initializing a histogram with clock argument The histogram API allows the user to specific which trace clock to use via a "clock=" string. The histogram is set up first before the clock is checked. If the passed in clock is not valid, it exits without fully fixing up the histogram leaving it on the list and a use-after-free can trigger. Update the clock argument first and if it fails then exit gracefully before the histogram trigger is placed on any lists. - Restore :mod: trailer after parsing in ftrace_set_clr_event The function ftrace_set_clr_event() modifies the parse string and needs to put it back to what was passed in. It searches for ":mod:" via a strsep() but fails to put back the first ':' in the string. Add back the ':' in the passed in string. - Take trace_array reference when opening a tracer options file The options files are dynamically created and some tracers add their own options. When a tracer adds their own list of options, the trace_array holding them has an array to hold the list of options for each tracer. This array increases in size via a krealloc(), and the new entry gets a newly allocated array to hold the options of the new tracer being added. The element in each entry of the tracer's option array holds a pointer back to the trace_array, a pointer to the tracer it is associated to, a pointer to the flags of the option. The issue is that these arrays are freed when the trace_array is freed when its instance it represents is removed from the instances directory. There's a race that an open of one of these options files can happen when the instance is being removed. Add a new helper function to be called by the open function of the options file to iterate all existing trace_arrays under a lock and find the one that has the given option element in one of it's tracer arrays. If found, then update the associated trace_array's reference counter to keep it from being freed. If not found, have the open call return -ENODEV. - Disable interrupts when acquiring the lock in rb_wake_up_waiters() The function rb_wake_up_waiters() assumes it will be called in interrupt context and does not disable irqs when taking cpu_buffer->reader_lock, which can be called in hard interrupt context. The issue is in PREEMPT_RT, this function is called in thread context leaving this lock open to a deadlock. Take the lock with interrupts disabled. - Use rcu_assign_pointer() for tmp_ops filter hash The tmp_ops used in update_ftrace_direct_mod() assigns its filter_hash field directly, but that field is annotated as __rcu and sparse complains. Assign it with rcu_assign_pointer() - Fix use-after-free in enable_trigger_private_data_free() The trace_event_call is accessed through the event_trigger_data's trace_event_file pointer to put the trace_event_call on freeing. The issue is that the trace_event_file data may have been freed already causing a use-after-free. Add a field to the event_trigger_data that points directly to the trace_event_call so that it can decrement its reference directly without needing to go through the trace_event_file. - Fix accounting of buffer data remote headers trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount the number of pages is needed for the asked for size as it doesn't take into account the meta data on each page. Add a helper function to do the calculation properly and use that in these functions. - Catch nr_page_va overflow in ring_buffer_desc sizing The number of pages per remote ring buffer is capped by ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to overflow that field would silently allocate a descriptor smaller than what was asked for. - Do not resize the subbuf order if any per_cpu buffer is disabled The mmapping of ring buffers disables resizing the subbuffers, but it is done per-cpu whereas the subbuf size change is done for all the per_cpu buffers under the buffer->mutex. It could change the size of some while the mapping is happening on others. Have the resize of the subbuf order check all the per_cpu buffers under the lock to see if any of them is disabled before starting and causing an inconsistency between buffers that are being mapped. * tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits) ring-buffer: Check resize_disabled before publishing the new subbuf order tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing tracing/remotes: Account for ring buffer page header in size calculation tracing: Don't dereference trace_event_file in deferred trigger free ftrace: Use rcu_assign_pointer() for tmp_ops filter hash ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters() tracing: Take trace_array reference when opening a tracer options file tracing: Fix ring_buffer_read_page_size() kernel-doc tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event() tracing: Fix memory corruption from a "STACKTRACE" histogram key tracing: Fix memory corruption from the histogram stacktrace modifier tracing: Undo the registration when enabling the histogram trigger fails tracing: Take the reference before publishing the named histogram trigger tracing: Set the trace clock before registering the histogram trigger tracing: Fix typo "preceeded" in comment tracing: Fix typo "availabe" in comment tracing: Let histogram values keep the percent and graph modifiers tracing: Keep the entry count when the histogram stats allocation fails tracing: Free histogram the field rejected for a bad modifier tracing: Free histogram the var ref when its initialization fails ... --- tools/testing/selftests/pipe/.gitignore | 1 + tools/testing/selftests/pipe/Makefile | 9 + tools/testing/selftests/pipe/pipe_bench.c | 616 ++++++++++++++++++++++++++++++ 3 files changed, 626 insertions(+) create mode 100644 tools/testing/selftests/pipe/.gitignore create mode 100644 tools/testing/selftests/pipe/Makefile create mode 100644 tools/testing/selftests/pipe/pipe_bench.c (limited to 'tools/testing/selftests/pipe') diff --git a/tools/testing/selftests/pipe/.gitignore b/tools/testing/selftests/pipe/.gitignore new file mode 100644 index 000000000..20b549361 --- /dev/null +++ b/tools/testing/selftests/pipe/.gitignore @@ -0,0 +1 @@ +pipe_bench diff --git a/tools/testing/selftests/pipe/Makefile b/tools/testing/selftests/pipe/Makefile new file mode 100644 index 000000000..1810c6801 --- /dev/null +++ b/tools/testing/selftests/pipe/Makefile @@ -0,0 +1,9 @@ +# SPDX-License-Identifier: GPL-2.0 +# Copyright (c) 2026 Meta Platforms, Inc. and affiliates +# Copyright (c) 2026 Breno Leitao + +CFLAGS += -O2 -Wall -Wextra -pthread + +TEST_GEN_PROGS := pipe_bench + +include ../lib.mk diff --git a/tools/testing/selftests/pipe/pipe_bench.c b/tools/testing/selftests/pipe/pipe_bench.c new file mode 100644 index 000000000..7e96429b8 --- /dev/null +++ b/tools/testing/selftests/pipe/pipe_bench.c @@ -0,0 +1,616 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * pipe_bench - exercise concurrent pipe operation + * + * N writer threads hammer a single pipe with multi-page writes; M reader + * threads drain it. Each writer records its own write() latency histogram. + * Multi-page writes (msgsize >= PAGE_SIZE) force the loop in + * anon_pipe_write() to call alloc_page(GFP_HIGHUSER | __GFP_ACCOUNT) under + * pipe->mutex, which is the critical section the patch shrinks. + * + * By default the benchmark sweeps writers in {1, 2, 5} x readers in + * {1, 5, 10} and prints one block per configuration so two runs (e.g. + * baseline vs patched) can be diffed directly. Pass -w and -r to run a + * single configuration instead. Pass --memory-pressure to spawn stress-ng + * alongside the sweep so the per-page alloc_page() path under pipe->mutex + * has to dip into reclaim. + * + * Copyright (c) 2026 Meta Platforms, Inc. and affiliates + * Copyright (c) 2026 Breno Leitao + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0])) +#define HIST_BUCKETS 32 + +static size_t g_msgsize = 16 * 4096; +static int g_duration = 3; +static int g_pipe_size = 1024 * 1024; +static int g_memory_pressure; + +static atomic_int g_stop; +static int g_pipe[2]; + +struct wstats { + uint64_t writes; + uint64_t bytes; + uint64_t lat_sum_ns; + uint64_t lat_max_ns; + uint64_t lat_hist[HIST_BUCKETS]; + char *buf; +}; + +struct rstats { + char *buf; +}; + +struct hist_totals { + uint64_t writes; + uint64_t bytes; + uint64_t lat_sum; + uint64_t lat_max; +}; + +static inline uint64_t now_ns(void) +{ + struct timespec ts; + + clock_gettime(CLOCK_MONOTONIC, &ts); + return (uint64_t)ts.tv_sec * 1000000000ull + (uint64_t)ts.tv_nsec; +} + +static inline int log2_bucket(uint64_t v) +{ + int b = 0; + + if (!v) + return 0; + while (v >>= 1) + b++; + return b < HIST_BUCKETS ? b : HIST_BUCKETS - 1; +} + +static void *writer(void *arg) +{ + struct wstats *s = arg; + + while (!atomic_load_explicit(&g_stop, memory_order_relaxed)) { + uint64_t t0 = now_ns(); + ssize_t n = write(g_pipe[1], s->buf, g_msgsize); + uint64_t dt = now_ns() - t0; + + if (n > 0) { + s->writes++; + s->bytes += (uint64_t)n; + s->lat_sum_ns += dt; + if (dt > s->lat_max_ns) + s->lat_max_ns = dt; + s->lat_hist[log2_bucket(dt)]++; + } else if (n < 0 && (errno == EPIPE || errno == EBADF)) { + break; + } + } + return NULL; +} + +static void *reader(void *arg) +{ + struct rstats *s = arg; + + /* + * Drain until EOF (write end closed by main). g_stop is not checked + * here on purpose: writers may be blocked in write() with the pipe + * full when g_stop is set, so the reader must keep draining until + * main closes the write end. + */ + for (;;) { + ssize_t n = read(g_pipe[0], s->buf, g_msgsize); + + if (n <= 0) + break; + } + return NULL; +} + +/* Sum per-writer stats and per-bucket counts into the caller's aggregates. */ +static void aggregate_wstats(struct wstats *all, int nw, + uint64_t agg[HIST_BUCKETS], + struct hist_totals *t) +{ + memset(t, 0, sizeof(*t)); + for (int i = 0; i < nw; i++) { + t->writes += all[i].writes; + t->bytes += all[i].bytes; + t->lat_sum += all[i].lat_sum_ns; + if (all[i].lat_max_ns > t->lat_max) + t->lat_max = all[i].lat_max_ns; + for (int b = 0; b < HIST_BUCKETS; b++) + agg[b] += all[i].lat_hist[b]; + } +} + +/* + * Walk @agg in order, returning the inclusive upper bound (in ns) of the + * log2 bucket where the running sum first reaches @target. + * + * A percentile is undefined with zero samples, and with very low sample + * counts integer truncation could make @target zero -- then "cum >= 0" + * would latch on the first (possibly empty) bucket. Callers must pass + * @target >= 1. + */ +static uint64_t bucket_at(const uint64_t agg[HIST_BUCKETS], uint64_t target) +{ + uint64_t cum = 0; + + for (int b = 0; b < HIST_BUCKETS; b++) { + /* HIST_BUCKETS <= 63, so (b + 1) is always a safe shift. */ + uint64_t upper = (1ULL << (b + 1)) - 1; + + cum += agg[b]; + if (cum >= target) + return upper; + } + return 0; +} + +static void compute_p50_p99(const uint64_t agg[HIST_BUCKETS], uint64_t writes, + uint64_t *p50, uint64_t *p99) +{ + uint64_t p50_target, p99_target; + + *p50 = *p99 = 0; + if (!writes) + return; + + p50_target = writes * 50 / 100; + p99_target = writes * 99 / 100; + if (!p50_target) + p50_target = 1; + if (!p99_target) + p99_target = 1; + + *p50 = bucket_at(agg, p50_target); + *p99 = bucket_at(agg, p99_target); +} + +static void print_summary(int nw, int nr, const struct hist_totals *t, + uint64_t p50, uint64_t p99) +{ + double sec = g_duration; + uint64_t avg_ns = t->writes ? t->lat_sum / t->writes : 0; + + printf("config: writers=%d readers=%d msgsize=%zu duration=%d pipe_size=%d memory_pressure=%s\n", + nw, nr, g_msgsize, g_duration, g_pipe_size, + g_memory_pressure ? "yes" : "no"); + printf("writes: total=%llu rate=%.0f/s\n", + (unsigned long long)t->writes, (double)t->writes / sec); + printf("throughput_MBps: %.2f\n", + ((double)t->bytes / sec) / (1024.0 * 1024.0)); + printf("lat_avg_ns: %llu\n", (unsigned long long)avg_ns); + printf("lat_p50_ns_upper: %llu\n", (unsigned long long)p50); + printf("lat_p99_ns_upper: %llu\n", (unsigned long long)p99); + printf("lat_max_ns: %llu\n", (unsigned long long)t->lat_max); +} + +static void summarize(struct wstats *all, int nw, int nr) +{ + uint64_t agg[HIST_BUCKETS] = {0}; + struct hist_totals t; + uint64_t p50, p99; + + aggregate_wstats(all, nw, agg, &t); + compute_p50_p99(agg, t.writes, &p50, &p99); + print_summary(nw, nr, &t, p50, p99); +} + +/* + * Child branch of fork(): restore SIGPIPE to default (parent ignores it), + * exec stress-ng, and on failure write the reason into @hs_wr before + * exiting. The parent observes EOF on hs_wr (closed via O_CLOEXEC) when + * exec succeeds. + */ +static void stress_ng_child(int hs_wr) __attribute__((noreturn)); +static void stress_ng_child(int hs_wr) +{ + char errbuf[256]; + + signal(SIGPIPE, SIG_DFL); + execlp("stress-ng", "stress-ng", + "--vm", "4", "--vm-bytes", "80%", + "--vm-method", "all", + (char *)NULL); + snprintf(errbuf, sizeof(errbuf), + "exec stress-ng failed: %s\n", strerror(errno)); + (void)!write(hs_wr, errbuf, strlen(errbuf)); + _exit(127); +} + +/* + * Read from the O_CLOEXEC handshake pipe. Anything readable means the + * child wrote an error before exec; EOF (n == 0) means the write-end + * closed because exec succeeded. Returns 0 on exec success, -1 if the + * child failed and was reaped. + */ +static int stress_ng_wait_handshake(int hs_rd, pid_t pid) +{ + struct pollfd pfd = { .fd = hs_rd, .events = POLLIN }; + char errbuf[256]; + int status; + int ret; + + ret = poll(&pfd, 1, 500); + if (ret <= 0) + return 0; + + ssize_t n = read(hs_rd, errbuf, sizeof(errbuf) - 1); + + if (n > 0) { + errbuf[n] = '\0'; + fputs(errbuf, stderr); + waitpid(pid, &status, 0); + return -1; + } + return 0; +} + +static pid_t spawn_stress_ng(void) +{ + int hs[2]; + pid_t pid; + + /* + * Handshake pipe: child writes one byte and _exit()s on exec + * failure. On exec success the O_CLOEXEC flag closes the write + * end, which the parent observes as EOF. This makes the "is + * stress-ng on $PATH?" check fail fast rather than silently. + */ + if (pipe2(hs, O_CLOEXEC) < 0) { + perror("pipe2"); + return -1; + } + + pid = fork(); + if (pid < 0) { + perror("fork"); + close(hs[0]); + close(hs[1]); + return -1; + } + if (pid == 0) { + close(hs[0]); + stress_ng_child(hs[1]); + } + + close(hs[1]); + if (stress_ng_wait_handshake(hs[0], pid) < 0) { + close(hs[0]); + return -1; + } + close(hs[0]); + + /* Give stress-ng a moment to map its VM regions before measuring. */ + sleep(1); + return pid; +} + +static void kill_stress_ng(pid_t pid) +{ + int status; + + if (pid <= 0) + return; + kill(pid, SIGTERM); + for (int i = 0; i < 20; i++) { + if (waitpid(pid, &status, WNOHANG) > 0) + return; + usleep(100 * 1000); + } + kill(pid, SIGKILL); + waitpid(pid, &status, 0); +} + +/* + * Allocate per-thread page-aligned buffers in main so a failed + * aligned_alloc() aborts the run before any thread starts. Workers used + * to allocate their own buffer and return NULL on failure, which left + * peers blocked in write()/read() with nobody to unblock them. + */ +static int alloc_thread_bufs(struct wstats *ws, int nw, + struct rstats *rs, int nr) +{ + for (int i = 0; i < nw; i++) { + ws[i].buf = aligned_alloc(4096, g_msgsize); + if (!ws[i].buf) { + fprintf(stderr, "writer %d: aligned_alloc(%zu) failed\n", + i, g_msgsize); + return -1; + } + memset(ws[i].buf, 0xAA, g_msgsize); + } + for (int i = 0; i < nr; i++) { + rs[i].buf = aligned_alloc(4096, g_msgsize); + if (!rs[i].buf) { + fprintf(stderr, "reader %d: aligned_alloc(%zu) failed\n", + i, g_msgsize); + return -1; + } + } + return 0; +} + +static void free_thread_bufs(struct wstats *ws, int nw, + struct rstats *rs, int nr) +{ + if (ws) + for (int i = 0; i < nw; i++) + free(ws[i].buf); + if (rs) + for (int i = 0; i < nr; i++) + free(rs[i].buf); +} + +static int start_readers(pthread_t *rt, struct rstats *rs, int nr, + int *created) +{ + for (int i = 0; i < nr; i++) { + int err = pthread_create(&rt[i], NULL, reader, &rs[i]); + + if (err) { + fprintf(stderr, "pthread_create reader %d: %s\n", + i, strerror(err)); + return -1; + } + (*created)++; + } + return 0; +} + +static int start_writers(pthread_t *wt, struct wstats *ws, int nw, + int *created) +{ + for (int i = 0; i < nw; i++) { + int err = pthread_create(&wt[i], NULL, writer, &ws[i]); + + if (err) { + fprintf(stderr, "pthread_create writer %d: %s\n", + i, strerror(err)); + return -1; + } + (*created)++; + } + return 0; +} + +static int open_bench_pipe(void) +{ + if (pipe(g_pipe) < 0) { + perror("pipe"); + return -1; + } + if (fcntl(g_pipe[1], F_SETPIPE_SZ, g_pipe_size) < 0) + perror("F_SETPIPE_SZ (continuing)"); + return 0; +} + +/* + * Normal termination: g_stop tells writers to leave the loop after the + * current write() returns. Closing the shared write-end fd means once + * the in-flight writes drain, readers see EOF and exit. Writers are not + * unblocked by EPIPE here -- g_pipe[0] stays open so readers can keep + * draining. + * + * Error path: some threads may have been created and others skipped, so + * writers could be blocked in write() with no reader making progress. + * Close both ends -- closing the read end is what delivers EPIPE to a + * blocked writer. + */ +static void stop_and_join(pthread_t *wt, int nw_created, + pthread_t *rt, int nr_created, int rc) +{ + atomic_store(&g_stop, 1); + close(g_pipe[1]); + if (rc < 0) + close(g_pipe[0]); + for (int i = 0; i < nw_created; i++) + pthread_join(wt[i], NULL); + for (int i = 0; i < nr_created; i++) + pthread_join(rt[i], NULL); + if (rc == 0) + close(g_pipe[0]); +} + +static int run_one(int nw, int nr) +{ + pthread_t *wt = NULL, *rt = NULL; + struct wstats *ws = NULL; + struct rstats *rs = NULL; + int nw_created = 0, nr_created = 0; + int rc = 0; + + atomic_store(&g_stop, 0); + + if (open_bench_pipe() < 0) + return -1; + + wt = calloc((size_t)nw, sizeof(*wt)); + rt = calloc((size_t)nr, sizeof(*rt)); + ws = calloc((size_t)nw, sizeof(*ws)); + rs = calloc((size_t)nr, sizeof(*rs)); + if (!wt || !rt || !ws || !rs) { + fprintf(stderr, "alloc failed\n"); + rc = -1; + goto teardown; + } + + if (alloc_thread_bufs(ws, nw, rs, nr) < 0) { + rc = -1; + goto teardown; + } + + if (start_readers(rt, rs, nr, &nr_created) < 0 || + start_writers(wt, ws, nw, &nw_created) < 0) { + rc = -1; + goto teardown; + } + + sleep((unsigned int)g_duration); + +teardown: + stop_and_join(wt, nw_created, rt, nr_created, rc); + + if (rc == 0) { + summarize(ws, nw, nr); + fflush(stdout); + } + + free_thread_bufs(ws, nw, rs, nr); + free(wt); + free(rt); + free(ws); + free(rs); + return rc; +} + +static void usage(const char *prog) +{ + fprintf(stderr, + "usage: %s [-w writers] [-r readers] [-s msgsize] [-d secs] [-p pipe_size] [--memory-pressure]\n" + " default: sweep writers={1,2,5} x readers={1,5,10}\n" + " --memory-pressure: spawn stress-ng (--vm 4 --vm-bytes 80%% --vm-method all) for the run\n", + prog); +} + +static int parse_args(int argc, char **argv, + int *writers_override, int *readers_override) +{ + static const struct option long_opts[] = { + {"memory-pressure", no_argument, NULL, 'M'}, + {0, 0, 0, 0}, + }; + int opt; + + while ((opt = getopt_long(argc, argv, "w:r:s:d:p:", + long_opts, NULL)) != -1) { + switch (opt) { + case 'w': + *writers_override = atoi(optarg); + break; + case 'r': + *readers_override = atoi(optarg); + break; + case 's': + g_msgsize = (size_t)atol(optarg); + break; + case 'd': + g_duration = atoi(optarg); + break; + case 'p': + g_pipe_size = atoi(optarg); + break; + case 'M': + g_memory_pressure = 1; + break; + default: + usage(argv[0]); + return -1; + } + } + return 0; +} + +/* + * aligned_alloc(4096, size) requires size to be a multiple of the + * alignment (C11); glibc returns NULL otherwise, which would make + * writer/reader threads silently exit and the run report zero writes. + * Validate up front instead. + */ +static int validate_args(void) +{ + if (g_msgsize == 0 || g_msgsize % 4096 != 0) { + fprintf(stderr, + "msgsize must be a positive multiple of 4096 (got %zu)\n", + g_msgsize); + return -1; + } + if (g_duration <= 0) { + fprintf(stderr, "duration must be > 0 seconds (got %d)\n", + g_duration); + return -1; + } + if (g_pipe_size <= 0) { + fprintf(stderr, "pipe_size must be > 0 bytes (got %d)\n", + g_pipe_size); + return -1; + } + return 0; +} + +static int run_sweep(void) +{ + static const int writers_sweep[] = {1, 2, 5}; + static const int readers_sweep[] = {1, 5, 10}; + + for (size_t i = 0; i < ARRAY_SIZE(writers_sweep); i++) { + for (size_t j = 0; j < ARRAY_SIZE(readers_sweep); j++) { + printf("---\n"); + if (run_one(writers_sweep[i], readers_sweep[j]) < 0) + return -1; + } + } + return 0; +} + +int main(int argc, char **argv) +{ + int writers_override = 0, readers_override = 0; + pid_t stress_pid = -1; + int rc = 0; + + if (parse_args(argc, argv, &writers_override, &readers_override) < 0) + return 1; + if (validate_args() < 0) + return 1; + + signal(SIGPIPE, SIG_IGN); + setvbuf(stdout, NULL, _IOLBF, 0); + setvbuf(stderr, NULL, _IOLBF, 0); + + fprintf(stderr, "pid=%d\n", getpid()); + fflush(stderr); + + if (g_memory_pressure) { + stress_pid = spawn_stress_ng(); + if (stress_pid < 0) { + fprintf(stderr, + "memory_pressure requested but stress-ng could not be spawned\n"); + return 1; + } + } + + if (writers_override > 0 || readers_override > 0) { + int nw = writers_override > 0 ? writers_override : 1; + int nr = readers_override > 0 ? readers_override : 1; + + rc = run_one(nw, nr) < 0 ? 1 : 0; + } else { + rc = run_sweep() < 0 ? 1 : 0; + } + + kill_stress_ng(stress_pid); + return rc; +} -- cgit v1.3.1