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vcl: always drain libc epoll with eventfds in ldp

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Otherwise if vcl epoll lt events are ignored by the app, libc and vcl mq
events are never drained.

Type: fix

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I1e22f6da46d56236c52714181f6c20dcb80a33a5
This commit is contained in:
Florin Coras
2023-03-05 11:45:38 -08:00
committed by Dave Wallace
parent 87767d82d7
commit c86662a213
1 changed files with 36 additions and 17 deletions
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53
src/vcl/ldp.c
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@@ -2413,8 +2413,10 @@ epoll_ctl (int epfd, int op, int fd, struct epoll_event *event)
* was acquired outside of the LD_PRELOAD process context.
* In any case, if we get one, punt it to libc_epoll_ctl.
*/
LDBG (1, "epfd %d: calling libc_epoll_ctl: op %d, fd %d"
" event %p", epfd, op, fd, event);
LDBG (1,
"epfd %d: calling libc_epoll_ctl: op %d, fd %d"
" events 0x%x",
epfd, op, fd, event ? event->events : 0);
rv = libc_epoll_ctl (epfd, op, fd, event);
goto done;
@@ -2427,8 +2429,10 @@ epoll_ctl (int epfd, int op, int fd, struct epoll_event *event)
if (vlsh != VLS_INVALID_HANDLE)
{
LDBG (1, "epfd %d: calling vls_epoll_ctl: ep_vlsh %d op %d, vlsh %u,"
" event %p", epfd, vep_vlsh, op, vlsh, event);
LDBG (1,
"epfd %d: calling vls_epoll_ctl: ep_vlsh %d op %d, vlsh %u,"
" events 0x%x",
epfd, vep_vlsh, op, vlsh, event ? event->events : 0);
rv = vls_epoll_ctl (vep_vlsh, op, vlsh, event);
if (rv != VPPCOM_OK)
@@ -2566,8 +2570,9 @@ static inline int
ldp_epoll_pwait_eventfd (int epfd, struct epoll_event *events,
int maxevents, int timeout, const sigset_t * sigmask)
{
int libc_epfd, rv = 0, num_ev, libc_num_ev, vcl_wups = 0;
struct epoll_event *libc_evts;
ldp_worker_ctx_t *ldpw;
int libc_epfd, rv = 0, num_ev, vcl_wups = 0;
vls_handle_t ep_vlsh;
ldp_init_check ();
@@ -2643,7 +2648,11 @@ ldp_epoll_pwait_eventfd (int epfd, struct epoll_event *events,
/* Request to only drain unhandled to prevent libc_epoll_wait starved */
rv = vls_epoll_wait (ep_vlsh, events, maxevents, -2);
if (rv > 0)
goto done;
{
timeout = 0;
if (rv >= maxevents)
goto done;
}
else if (PREDICT_FALSE (rv < 0))
{
errno = -rv;
@@ -2652,30 +2661,40 @@ ldp_epoll_pwait_eventfd (int epfd, struct epoll_event *events,
}
epoll_again:
rv = libc_epoll_pwait (libc_epfd, events, maxevents, timeout, sigmask);
if (rv <= 0)
goto done;
for (int i = 0; i < rv; i++)
libc_evts = &events[rv];
libc_num_ev =
libc_epoll_pwait (libc_epfd, libc_evts, maxevents - rv, timeout, sigmask);
if (libc_num_ev <= 0)
{
if (events[i].data.fd == ldpw->vcl_mq_epfd)
rv = rv >= 0 ? rv : -1;
goto done;
}
for (int i = 0; i < libc_num_ev; i++)
{
if (libc_evts[i].data.fd == ldpw->vcl_mq_epfd)
{
/* We should remove mq epoll fd from events. */
rv--;
if (i != rv)
libc_num_ev--;
if (i != libc_num_ev)
{
events[i].events = events[rv].events;
events[i].data.u64 = events[rv].data.u64;
libc_evts[i].events = libc_evts[libc_num_ev].events;
libc_evts[i].data.u64 = libc_evts[libc_num_ev].data.u64;
}
num_ev = vls_epoll_wait (ep_vlsh, &events[rv], maxevents - rv, 0);
num_ev = vls_epoll_wait (ep_vlsh, &libc_evts[libc_num_ev],
maxevents - libc_num_ev, 0);
if (PREDICT_TRUE (num_ev > 0))
rv += num_ev;
/* Woken up by vcl but no events generated. Accept it once */
if (rv == 0 && vcl_wups++ < 1)
if (rv == 0 && libc_num_ev == 0 && timeout && vcl_wups++ < 1)
goto epoll_again;
break;
}
}
rv += libc_num_ev;
done:
return rv;
}