[PATCH net-next v6 3/4] eventpoll: Add per-epoll prefer busy poll option
From: Joe Damato <hidden>
Date: 2024-02-05 21:05:06
Also in:
linux-fsdevel, lkml, netdev
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
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 <redacted> --- fs/eventpoll.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 3985434df527..a69ee11682b9 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c@@ -231,6 +231,7 @@ struct eventpoll { u64 busy_poll_usecs; /* busy poll packet budget */ u16 busy_poll_budget; + bool prefer_busy_poll; #endif #ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -440,13 +441,14 @@ 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; /*
@@ -2105,6 +2107,7 @@ 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);
--
2.25.1