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authorwanghanlin <wanghanlin@corp.netease.com>2021-03-18 20:00:41 +0800
committerFlorin Coras <florin.coras@gmail.com>2021-03-22 14:23:06 +0000
commit8919fec5acb14d176b992b71108f9a912d98161e (patch)
treeb99473dbba9e6d91c1cc6285ec35c256373aa749
parent156158f06d725d9301940783dff8ccdcc4a01b9b (diff)
vcl: fix libc epoll pwait starved
We call vls_epoll_wait with 0 timeout to process unhandled_evts_vector in ldp_epoll_pwait_eventfd. But vls_epoll_wait will then call vppcom_epoll_wait_eventfd to process events in event queue. If there are continuous events to be handled, then libc_epoll_pwait have no chance to be called. Type: fix Signed-off-by: wanghanlin <wanghanlin@corp.netease.com> Change-Id: Ia4f61d0d438a3475bfde9f6715805274671d4e75
-rw-r--r--src/vcl/ldp.c3
-rw-r--r--src/vcl/vppcom.c3
2 files changed, 5 insertions, 1 deletions
diff --git a/src/vcl/ldp.c b/src/vcl/ldp.c
index a10d4d02fb4..64a4e7c77db 100644
--- a/src/vcl/ldp.c
+++ b/src/vcl/ldp.c
@@ -2516,7 +2516,8 @@ ldp_epoll_pwait_eventfd (int epfd, struct epoll_event *events,
ldpw->mq_epfd_added = 1;
}
- rv = vls_epoll_wait (ep_vlsh, events, maxevents, 0);
+ /* 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;
else if (PREDICT_FALSE (rv < 0))
diff --git a/src/vcl/vppcom.c b/src/vcl/vppcom.c
index cc4464b162e..3e4ba2fb953 100644
--- a/src/vcl/vppcom.c
+++ b/src/vcl/vppcom.c
@@ -3042,6 +3042,9 @@ vppcom_epoll_wait (uint32_t vep_handle, struct epoll_event *events,
}
vec_reset_length (wrk->unhandled_evts_vector);
}
+ /* Request to only drain unhandled */
+ if ((int) wait_for_time == -2)
+ return n_evts;
if (vcm->cfg.use_mq_eventfd)
return vppcom_epoll_wait_eventfd (wrk, events, maxevents, n_evts,