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Fri, 09 Feb 2024 13:15:49 -0800 (PST) X-Forwarded-Encrypted: i=1; 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 Received: from localhost.localdomain ([2620:11a:c018:0:ea8:be91:8d1:f59b]) by smtp.gmail.com with ESMTPSA id x23-20020aa79197000000b006e05c801748sm969629pfa.199.2024.02.09.13.15.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Feb 2024 13:15:49 -0800 (PST) From: Joe Damato To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: chuck.lever@oracle.com, jlayton@kernel.org, linux-api@vger.kernel.org, brauner@kernel.org, edumazet@google.com, davem@davemloft.net, alexander.duyck@gmail.com, sridhar.samudrala@intel.com, kuba@kernel.org, willemdebruijn.kernel@gmail.com, weiwan@google.com, David.Laight@ACULAB.COM, arnd@arndb.de, sdf@google.com, amritha.nambiar@intel.com, Joe Damato , Alexander Viro , Jan Kara , linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure)) Subject: [PATCH net-next v7 3/4] eventpoll: Add per-epoll prefer busy poll option Date: Fri, 9 Feb 2024 21:15:23 +0000 Message-Id: <20240209211528.51234-4-jdamato@fastly.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240209211528.51234-1-jdamato@fastly.com> References: <20240209211528.51234-1-jdamato@fastly.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 Acked-by: Stanislav Fomichev Reviewed-by: Jakub Kicinski Reviewed-by: Eric Dumazet --- fs/eventpoll.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index ed83ae33dd45..1b8d01af0c2c 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -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);