mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

eventpoll: Add per-epoll prefer busy poll option 

When using epoll-based busy poll, the prefer_busy_poll option is hardcoded
to false. Users may want to enable prefer_busy_poll to be used in
conjunction with gro_flush_timeout and defer_hard_irqs_count to keep device
IRQs masked.

Other busy poll methods allow enabling or disabling prefer busy poll via
SO_PREFER_BUSY_POLL, but epoll-based busy polling uses a hardcoded value.

Fix this edge case by adding support for a per-epoll context
prefer_busy_poll option. The default is false, as it was hardcoded before
this change.

Signed-off-by: Joe Damato <jdamato@fastly.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Joe Damato 2024-02-13 06:16:44 +00:00 committed by David S. Miller
parent c6aa2a7778
commit de57a25108
1 changed files with 5 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
fs/eventpoll.c
View File

@ -231,6 +231,7 @@ struct eventpoll {
u32 busy_poll_usecs;
/* busy poll packet budget */
u16 busy_poll_budget;
bool prefer_busy_poll;
#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
@ -438,13 +439,14 @@ static bool ep_busy_loop(struct eventpoll *ep, int nonblock)
{
unsigned int napi_id = READ_ONCE(ep->napi_id);
u16 budget = READ_ONCE(ep->busy_poll_budget);
bool prefer_busy_poll = READ_ONCE(ep->prefer_busy_poll);
if (!budget)
budget = BUSY_POLL_BUDGET;
if (napi_id >= MIN_NAPI_ID && ep_busy_loop_on(ep)) {
napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep, false,
budget);
napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end,
ep, prefer_busy_poll, budget);
if (ep_events_available(ep))
return true;
/*
@ -2098,6 +2100,7 @@ static int do_epoll_create(int flags)
#ifdef CONFIG_NET_RX_BUSY_POLL
ep->busy_poll_usecs = 0;
ep->busy_poll_budget = 0;
ep->prefer_busy_poll = false;
#endif
ep->file = file;
fd_install(fd, file);