diff mbox series

[net-next,v4,4/7] eventpoll: Trigger napi_busy_loop, if prefer_busy_poll is set

Message ID 20241102005214.32443-5-jdamato@fastly.com (mailing list archive)
State New
Headers show
Series Suspend IRQs during application busy periods | expand

Commit Message

Joe Damato Nov. 2, 2024, 12:52 a.m. UTC 
From: Martin Karsten <mkarsten@uwaterloo.ca>

Setting prefer_busy_poll now leads to an effectively nonblocking
iteration though napi_busy_loop, even when busy_poll_usecs is 0.

Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca>
Co-developed-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Joe Damato <jdamato@fastly.com>
Tested-by: Martin Karsten <mkarsten@uwaterloo.ca>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
---
 v1 -> v2:
   - Rebased to apply now that commit b9ca079dd6b0 ("eventpoll: Annotate
     data-race of busy_poll_usecs") has been picked up from VFS.

 fs/eventpoll.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Samudrala, Sridhar Nov. 2, 2024, 11:33 p.m. UTC | #1 
On 11/1/2024 7:52 PM, Joe Damato wrote:
> From: Martin Karsten <mkarsten@uwaterloo.ca>
> 
> Setting prefer_busy_poll now leads to an effectively nonblocking
> iteration though napi_busy_loop, even when busy_poll_usecs is 0.
> 
> Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca>
> Co-developed-by: Joe Damato <jdamato@fastly.com>
> Signed-off-by: Joe Damato <jdamato@fastly.com>
> Tested-by: Joe Damato <jdamato@fastly.com>
> Tested-by: Martin Karsten <mkarsten@uwaterloo.ca>
> Acked-by: Stanislav Fomichev <sdf@fomichev.me>
> ---
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
diff mbox series

Patch

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 1ae4542f0bd8..f9e0d9307dad 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -420,7 +420,9 @@  static bool busy_loop_ep_timeout(unsigned long start_time,
 
 static bool ep_busy_loop_on(struct eventpoll *ep)
 {
-	return !!READ_ONCE(ep->busy_poll_usecs) || net_busy_loop_on();
+	return !!READ_ONCE(ep->busy_poll_usecs) ||
+	       READ_ONCE(ep->prefer_busy_poll) ||
+	       net_busy_loop_on();
 }
 
 static bool ep_busy_loop_end(void *p, unsigned long start_time)