From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 14 Aug 2026 15:43:51 -0700 Subject: Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEAD Changes: Make expedited grace periods expedite normal RCU callbacks Miscellaneous fixes: * Improve diagnostic output with character task states. * Mark accesses to inform KCSAN of concurrency design. * Move from kmalloc() to kmalloc_obj(). * Documentation updates. * Improve handling of RCU deferred quiescent states. * Clean up unused function arguments and structure fields. * Reduce show_rcu_gp_kthreads() stack space. Tasks RCU updates: * Clean up after SRCU re-implementation of Tasks Trace RCU. * Mark accesses to inform KCSAN of concurrency design. * Add ->lazy_timer status to diagnostic output. * Remove an unnecessary memory barrier. * Fix a data race, courtesy of KCSAN. * Documentation updates. * Convert cond_resched_tasks_rcu_qs() from macro to static inline function. SRCU updates: * Add Rust helpers for SRCU. * Avoid losing queued work at cleanup_srcu_struct() time. Torture-test updates: * Preparation work for immediate RCU priority deboosting. * Test RCU readers from real interrupt handlers (as opposed to softirq). * Simplify code through use of cpumask_next_wrap(). * Improve diagnostic output with character task states. * Add rcutorture.nwriters parameter to allow lightweight stall testing, and rcutorture.stall_only to make doing so easier. * Test an RCU Tasks Trace grace period implying an RCU grace period. * Make RCU Tasks Trace torturing track reader batches. * Fix a data race, courtesy of KCSAN. * Plug a shuffle_tmp_mask memory leak on kthread spawn failure. --- tools/perf/util/strbuf.c | 170 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 170 insertions(+) create mode 100644 tools/perf/util/strbuf.c (limited to 'tools/perf/util/strbuf.c') diff --git a/tools/perf/util/strbuf.c b/tools/perf/util/strbuf.c new file mode 100644 index 000000000..a64a37628 --- /dev/null +++ b/tools/perf/util/strbuf.c @@ -0,0 +1,170 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "cache.h" +#include "debug.h" +#include "strbuf.h" +#include +#include +#include +#include +#include +#include +#include + +/* + * Used as the default ->buf value, so that people can always assume + * buf is non NULL and ->buf is NUL terminated even for a freshly + * initialized strbuf. + */ +char strbuf_slopbuf[1]; + +int strbuf_init(struct strbuf *sb, ssize_t hint) +{ + sb->alloc = sb->len = 0; + sb->buf = strbuf_slopbuf; + if (hint) + return strbuf_grow(sb, hint); + return 0; +} + +void strbuf_release(struct strbuf *sb) +{ + if (sb->alloc) { + zfree(&sb->buf); + strbuf_init(sb, 0); + } +} + +char *strbuf_detach(struct strbuf *sb, size_t *sz) +{ + char *res = sb->alloc ? sb->buf : NULL; + if (sz) + *sz = sb->len; + strbuf_init(sb, 0); + return res; +} + +int strbuf_grow(struct strbuf *sb, size_t extra) +{ + char *buf; + size_t nr = sb->len + extra + 1; + + if (nr < sb->alloc) + return 0; + + if (nr <= sb->len) + return -E2BIG; + + if (alloc_nr(sb->alloc) > nr) + nr = alloc_nr(sb->alloc); + + /* + * Note that sb->buf == strbuf_slopbuf if sb->alloc == 0, and it is + * a static variable. Thus we have to avoid passing it to realloc. + */ + buf = realloc(sb->alloc ? sb->buf : NULL, nr * sizeof(*buf)); + if (!buf) + return -ENOMEM; + + sb->buf = buf; + sb->alloc = nr; + return 0; +} + +int strbuf_addch(struct strbuf *sb, int c) +{ + int ret = strbuf_grow(sb, 1); + if (ret) + return ret; + + sb->buf[sb->len++] = c; + sb->buf[sb->len] = '\0'; + return 0; +} + +int strbuf_add(struct strbuf *sb, const void *data, size_t len) +{ + int ret = strbuf_grow(sb, len); + if (ret) + return ret; + + memcpy(sb->buf + sb->len, data, len); + return strbuf_setlen(sb, sb->len + len); +} + +static int strbuf_addv(struct strbuf *sb, const char *fmt, va_list ap) +{ + int len, ret; + va_list ap_saved; + + if (!strbuf_avail(sb)) { + ret = strbuf_grow(sb, 64); + if (ret) + return ret; + } + + va_copy(ap_saved, ap); + len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap); + if (len < 0) { + va_end(ap_saved); + return len; + } + if (len > strbuf_avail(sb)) { + ret = strbuf_grow(sb, len); + if (ret) { + va_end(ap_saved); + return ret; + } + len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap_saved); + if (len > strbuf_avail(sb)) { + pr_debug("this should not happen, your vsnprintf is broken"); + va_end(ap_saved); + return -EINVAL; + } + } + va_end(ap_saved); + return strbuf_setlen(sb, sb->len + len); +} + +int strbuf_addf(struct strbuf *sb, const char *fmt, ...) +{ + va_list ap; + int ret; + + va_start(ap, fmt); + ret = strbuf_addv(sb, fmt, ap); + va_end(ap); + return ret; +} + +ssize_t strbuf_read(struct strbuf *sb, int fd, ssize_t hint) +{ + size_t oldlen = sb->len; + size_t oldalloc = sb->alloc; + int ret; + + ret = strbuf_grow(sb, hint ? hint : 8192); + if (ret) + return ret; + + for (;;) { + ssize_t cnt; + + cnt = read(fd, sb->buf + sb->len, sb->alloc - sb->len - 1); + if (cnt < 0) { + if (oldalloc == 0) + strbuf_release(sb); + else + strbuf_setlen(sb, oldlen); + return cnt; + } + if (!cnt) + break; + sb->len += cnt; + ret = strbuf_grow(sb, 8192); + if (ret) + return ret; + } + + sb->buf[sb->len] = '\0'; + return sb->len - oldlen; +} -- cgit v1.3.1