On 07/02/2026 06:09, Stephen Hemminger wrote: > On Fri, 6 Feb 2026 17:20:53 +0000 > Kevin Traynor <[email protected]> wrote: > >> A busy-loop may occur when there are EPOLLERR, EPOLLHUP or >> EPOLLRDHUP epoll events for the devx interrupt fd. >> >> This may happen if the interrupt fd is deleted, if the device >> is unbound from mlx5_core kernel driver or if the device is >> removed by the mlx5 kernel driver as part of LAG setup. >> >> When that occurs, there is no data to be read and in the devx >> interrupt handler an EAGAIN is returned on the first call to >> devx_get_async_cmd_comp, but this is not checked. >> >> As the interrupt is not removed or condition reset, it causes >> an interrupt processing busy-loop, which leads to the dpdk-intr >> thread going to 100% CPU. >> >> e.g. >> epoll_wait >> (6, [{events=EPOLLIN|EPOLLRDHUP, data={u32=28, u64=28}}], 8, -1) = 1 >> read(28, 0x7f1f5c7fc2f0, 40) >> = -1 EAGAIN (Resource temporarily unavailable) >> epoll_wait >> (6, [{events=EPOLLIN|EPOLLRDHUP, data={u32=28, u64=28}}], 8, -1) = 1 >> read(28, 0x7f1f5c7fc2f0, 40) >> = -1 EAGAIN (Resource temporarily unavailable) >> >> Add a check for an EAGAIN return from devx_get_async_cmd_comp on the >> first read. If that happens, unregister the callback to prevent looping. >> >> Bugzilla ID: 1873 >> Fixes: f15db67df09c ("net/mlx5: accelerate DV flow counter query") >> Cc: [email protected] >> >> Signed-off-by: Kevin Traynor <[email protected]> > > AI spotted this, I didn't... > > > Errors: > > Line 139: Unnecessary semicolon after closing brace > > c > > }; > > Should be: > c > > } > > Lines 142-146: Block comment uses incorrect style Block comments in C > code should use /* and */ style, not /** which is reserved for documentation > comments. > > c > > /** > * no data and EAGAIN indicate there is an error or > * disconnect state. Unregister callback to prevent > * interrupt busy-looping. > */ > > Should be: > c > > /* > * no data and EAGAIN indicate there is an error or > * disconnect state. Unregister callback to prevent > * interrupt busy-looping. > */ > > Warnings: > > Logic clarity: The variable data_read is set to true inside the while > loop but never checked when data WAS read. Consider if data_read is the > clearest way to express this condition. >
Ack above. Thanks.Will be fixed in v3.
