----- On Aug 1, 2018, at 2:54 PM, Eric Wong normalper...@yhbt.net wrote: > Users may want to use alternative sleeping behavior instead of > `poll'. Make CDS_WFCQ_WAIT_SLEEP a macro which may be defined > before including wfcqueue.h. > > This alternative behavior could include logging, performing > low-priority cleanup work, sleeping a shorter/longer interval > or any combination of that. > > This will also make integration into glibc easier, as `poll' > linkage causes conformance test failures even when relegated > to an impossible code path: > https://public-inbox.org/libc-alpha/20180801092626.jrwyrojfye4avcis@whir/
Rather than introducing a macro here, can we extend the API to pass a callback and a private pointer that would perform the sleeping behavior requested by the caller ? Thanks, Mathieu > > Signed-off-by: Eric Wong <normalper...@yhbt.net> > --- > include/urcu/static/wfcqueue.h | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/include/urcu/static/wfcqueue.h b/include/urcu/static/wfcqueue.h > index 67ac05f..3f56493 100644 > --- a/include/urcu/static/wfcqueue.h > +++ b/include/urcu/static/wfcqueue.h > @@ -223,6 +223,23 @@ static inline bool _cds_wfcq_enqueue(cds_wfcq_head_ptr_t > head, > return ___cds_wfcq_append(head, tail, new_tail, new_tail); > } > > +/* > + * CDS_WFCQ_WAIT_SLEEP: > + * > + * By default, this sleeps for the given @msec milliseconds. > + * This is a macro which LGPL users may #define themselves before > + * including wfcqueue.h to override the default behavior (e.g. > + * to log a warning or perform other background work). > + */ > +#ifndef CDS_WFCQ_WAIT_SLEEP > +#define CDS_WFCQ_WAIT_SLEEP(msec) ___cds_wfcq_wait_sleep((msec)) > +#endif > + > +static inline void ___cds_wfcq_wait_sleep(int msec) > +{ > + (void) poll(NULL, 0, msec); > +} > + > /* > * ___cds_wfcq_busy_wait: adaptative busy-wait. > * > @@ -234,7 +251,7 @@ ___cds_wfcq_busy_wait(int *attempt, int blocking) > if (!blocking) > return 1; > if (++(*attempt) >= WFCQ_ADAPT_ATTEMPTS) { > - (void) poll(NULL, 0, WFCQ_WAIT); /* Wait for 10ms */ > + CDS_WFCQ_WAIT_SLEEP(WFCQ_WAIT); /* Wait for 10ms */ > *attempt = 0; > } else { > caa_cpu_relax(); > -- > EW -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev