From patchwork Sat Nov 2 00:52:01 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joe Damato X-Patchwork-Id: 13859858 Received: from mail-pf1-f178.google.com (mail-pf1-f178.google.com [209.85.210.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1138C14B088 for ; Sat, 2 Nov 2024 00:54:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.178 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730508870; cv=none; b=mCFJqq3uiy4eAXJp3/a6c/U7u1+tu7NT/ue+9iSAwKi0slPUdGcotN+YdMJ69/W0chq+flXQGTHVdENfE3a29z8QGB4UevTEl4wef2yyDVfkUihkWCGGoEO2E8ilnoNt05zxWSiRIfE+5LhZzs8bo8u5XXBUc9rbhKv8TeGbEHA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730508870; c=relaxed/simple; bh=nTVHqzMjxVaFGtFwKysoiZKk4YEWDQibSQdexzn6DUQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=qOoGU6uytk9uh+onjC8RdO80SAYAg2cIKnFwlOT85JBePmzhjP2opQ0t2ouIJbCA2wPI9JokVChhxXAKAFSNm1J9zqlsgKT0c5r76N6/EuM/kRxLFujXfESa817ug0UEtqNUIifn9j5yBLno/8VkdSW5HDPFCqtLn0RZWwJNzUc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fastly.com; spf=pass smtp.mailfrom=fastly.com; dkim=pass (1024-bit key) header.d=fastly.com header.i=@fastly.com header.b=DBVb4zCg; arc=none smtp.client-ip=209.85.210.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fastly.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fastly.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=fastly.com header.i=@fastly.com header.b="DBVb4zCg" Received: by mail-pf1-f178.google.com with SMTP id d2e1a72fcca58-720c2db824eso2059430b3a.0 for ; Fri, 01 Nov 2024 17:54:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fastly.com; s=google; t=1730508866; x=1731113666; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=PhVjl1Gry+K7A+Im8XGVxnCvKP7p4PT8RH2VXkmIRG8=; b=DBVb4zCg0b0m+ITRxIDBx/rBlI0npPy8CqDt8RQ6bmvcDnI9eFIGCYDubmwbOjwNME N1CkCFCL0iwNDR0GnsLtA71BsLhUOiXwDEfrQSOEJiKrfftTA/dZvuADhgN4eX/HCTnL TvMLu7zpG++b40o+W6UdRgx0IY+SPnhFmuuQs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730508866; x=1731113666; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=PhVjl1Gry+K7A+Im8XGVxnCvKP7p4PT8RH2VXkmIRG8=; b=T7EkLDXDlvYlJmAAwTm929XNUBg+AEduqnPlUhUAQoPbbg/NV0x+eMMFfJ7kv8AuAl U6zzc94APQyWm6kxLef3JVw5HQnM+4+UrBusu93ngtyS6lIVk2CRAae2uhnGWe+zJXGZ IhRA8c/eltwha3tTRf5bHg7StR8hC8gunRsIiZ5iJEtO5VUTi1X8Fmc99kZ3KlQYRI3y 5xHG3pcYM+10jxLrrxE4qdTfuioMBWHnMXfitDequalBIdVd9LIR8G+gJwUBzhlN2Gsf vYLWEI3vQ2sqAIVmQ+xx1lDt9l3qpquDqjIUGswoWafowMe/gFYjamuMMkkM3D/c8NUl ykQw== X-Forwarded-Encrypted: i=1; AJvYcCX1Q9hv5R53gebwl/rmjChxB1r8AW2tmDmGjA2wYNxBLaHL9pUi7VVkuPofCswuIrxtclcIqn9oxO46pToU@vger.kernel.org X-Gm-Message-State: AOJu0YzNEW7MZPHFZTuISDjgbbF7OUCHIIlIOhGnDpgLa8ubcmqGzPmP EDrCqCm5JsfPG/exW817/HzFRt9TaEZy8twHhO+bg2SvjRADeonAui7SHVmA81g= X-Google-Smtp-Source: AGHT+IGDiV9QNNnfOJtUm4iKxVFroPyJZds/ckB2iebIxmJz87BZxpGxHjbsQSGczcnmCMvwIPaMbw== X-Received: by 2002:a05:6a00:3d11:b0:71e:4bfb:a1f9 with SMTP id d2e1a72fcca58-7206308e017mr32751796b3a.22.1730508866252; Fri, 01 Nov 2024 17:54:26 -0700 (PDT) Received: from localhost.localdomain ([2620:11a:c019:0:65e:3115:2f58:c5fd]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-720bc3152fesm3274549b3a.195.2024.11.01.17.54.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 01 Nov 2024 17:54:25 -0700 (PDT) From: Joe Damato To: netdev@vger.kernel.org Cc: bagasdotme@gmail.com, pabeni@redhat.com, namangulati@google.com, edumazet@google.com, amritha.nambiar@intel.com, sridhar.samudrala@intel.com, sdf@fomichev.me, peter@typeblog.net, m2shafiei@uwaterloo.ca, bjorn@rivosinc.com, hch@infradead.org, willy@infradead.org, willemdebruijn.kernel@gmail.com, skhawaja@google.com, kuba@kernel.org, Martin Karsten , Joe Damato , Alexander Viro , Christian Brauner , Jan Kara , linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure)), linux-kernel@vger.kernel.org (open list) Subject: [PATCH net-next v4 5/7] eventpoll: Control irq suspension for prefer_busy_poll Date: Sat, 2 Nov 2024 00:52:01 +0000 Message-Id: <20241102005214.32443-6-jdamato@fastly.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20241102005214.32443-1-jdamato@fastly.com> References: <20241102005214.32443-1-jdamato@fastly.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Martin Karsten 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 Co-developed-by: Joe Damato Signed-off-by: Joe Damato Tested-by: Joe Damato Tested-by: Martin Karsten Acked-by: Stanislav Fomichev Reviewed-by: Sridhar Samudrala --- rfc -> v1: - move irq resume code from ep_free to a helper which either resumes IRQs or does nothing if !defined(CONFIG_NET_RX_BUSY_POLL). fs/eventpoll.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index f9e0d9307dad..36a657594352 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -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 +2032,10 @@ 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) { + ep_suspend_napi_irqs(ep); return res; + } } if (timed_out)