Kernel/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-01-01 18:53:30 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

eventpoll: Control irq suspension for prefer_busy_poll

Browse Source 
When events are reported to userland and prefer_busy_poll is set, irqs
are temporarily suspended using napi_suspend_irqs.

If no events are found and ep_poll would go to sleep, irq suspension is
cancelled using napi_resume_irqs.

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>
Link: https://patch.msgid.link/20241109050245.191288-5-jdamato@fastly.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Martin Karsten 2024-11-09 05:02:34 +00:00 committed by Jakub Kicinski
parent ab5b28b007
commit 8a6de2627f
1 changed files with 31 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
fs/eventpoll.c
View File

@ -457,6 +457,8 @@ static bool ep_busy_loop(struct eventpoll *ep, int nonblock)
* it back in when we have moved a socket with a valid NAPI
* ID onto the ready list.
*/
if (prefer_busy_poll)
napi_resume_irqs(napi_id);
ep->napi_id = 0;
return false;
}
@ -540,6 +542,22 @@ static long ep_eventpoll_bp_ioctl(struct file *file, unsigned int cmd,
}
}
static void ep_suspend_napi_irqs(struct eventpoll *ep)
{
unsigned int napi_id = READ_ONCE(ep->napi_id);
if (napi_id >= MIN_NAPI_ID && READ_ONCE(ep->prefer_busy_poll))
napi_suspend_irqs(napi_id);
}
static void ep_resume_napi_irqs(struct eventpoll *ep)
{
unsigned int napi_id = READ_ONCE(ep->napi_id);
if (napi_id >= MIN_NAPI_ID && READ_ONCE(ep->prefer_busy_poll))
napi_resume_irqs(napi_id);
}
#else
static inline bool ep_busy_loop(struct eventpoll *ep, int nonblock)
@ -557,6 +575,14 @@ static long ep_eventpoll_bp_ioctl(struct file *file, unsigned int cmd,
return -EOPNOTSUPP;
}
static void ep_suspend_napi_irqs(struct eventpoll *ep)
{
}
static void ep_resume_napi_irqs(struct eventpoll *ep)
{
}
#endif /* CONFIG_NET_RX_BUSY_POLL */
/*
@ -788,6 +814,7 @@ static bool ep_refcount_dec_and_test(struct eventpoll *ep)
static void ep_free(struct eventpoll *ep)
{
ep_resume_napi_irqs(ep);
mutex_destroy(&ep->mtx);
free_uid(ep->user);
wakeup_source_unregister(ep->ws);
@ -2005,8 +2032,11 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
* trying again in search of more luck.
*/
res = ep_send_events(ep, events, maxevents);
if (res)
if (res) {
if (res > 0)
ep_suspend_napi_irqs(ep);
return res;
}
}
if (timed_out)