Messages in this thread | | | Date | Fri, 16 Jul 2021 13:29:15 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [RFC PATCH 03/10] perf workqueue: add threadpool start and stop functions |
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Em Fri, Jul 16, 2021 at 03:53:58PM +0200, Riccardo Mancini escreveu: > On Thu, 2021-07-15 at 16:48 -0700, Namhyung Kim wrote: > > On Tue, Jul 13, 2021 at 5:11 AM Riccardo Mancini <rickyman7@gmail.com> wrote: > > > +++ b/tools/perf/util/workqueue/threadpool.c > > [SNIP] > > > +/** > > > + * wait_thread - receive ack from thread > > > + * > > > + * NB: call only from main thread! > > > + */ > > > +static int wait_thread(struct thread_struct *thread) > > > +{ > > > + int res; > > > + enum thread_msg msg = THREAD_MSG__UNDEFINED; > > > + > > > + res = read(thread->pipes.from[0], &msg, sizeof(msg)); > > > + if (res < 0) {
> > Maybe it needs to handle -EINTR.
> Its behaviour should be retry, right? > Since these reads are used multiple times in the code, maybe I'm better off > writing a wrapper function handling also EINTR.
Take a look at readn():
tools/lib/perf/lib.c
static ssize_t ion(bool is_read, int fd, void *buf, size_t n) { void *buf_start = buf; size_t left = n;
while (left) { /* buf must be treated as const if !is_read. */ ssize_t ret = is_read ? read(fd, buf, left) : write(fd, buf, left);
if (ret < 0 && errno == EINTR) continue; if (ret <= 0) return ret;
left -= ret; buf += ret; }
BUG_ON((size_t)(buf - buf_start) != n); return n; }
/* * Read exactly 'n' bytes or return an error. */ ssize_t readn(int fd, void *buf, size_t n) { return ion(true, fd, buf, n); } - Arnaldo
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