From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (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 7FC4D367B90 for ; Tue, 18 Aug 2026 23:02:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787094123; cv=none; b=Lcm2Y5pUJumAiajBA/rPtcQluC0eluukj6gS70htfboIiIxNUd2QWB7ZkL7tcEGTOUWQrRBsLHYC4p4Fare52lLalTICLYyFDKAZhZQoNcUZysWmC97LF6OvaEKt3P65n89gh6t8fhGB+6O52X1ULMwSX9D1zwfDA4DL1jbd6zs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787094123; c=relaxed/simple; bh=LFNPoDeeTwavqXDYvxKz/k1t7gN3cxa/PZ/r6DBfaz4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XUelhcvjxTENF8jN2IGwia4u0iJpockLfpzV1sKCyk662jUbdK9JSu5Yg8N6iiAbTgja9LZMSRFyr9Vnokk0vdIskt5JkEHzbSWgv9pvjLe5ExpQAGzQte0d28sx4zjRYMK4w2RvJKk1w8fb7XrDmfOuW97sPjVJ3XH31C1z8X0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=B/xOsERq; arc=none smtp.client-ip=209.85.214.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="B/xOsERq" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-2d049069377so3998315ad.0 for ; Tue, 18 Aug 2026 16:02:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1787094122; x=1787698922; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=jjfWQTULW6kpWj4uQcqe65fiA3Rop9X8RDu4HH8k3wc=; b=B/xOsERqIgCHWDOaMzy5GePw25OdJ9GeVqYJEzDQPsIyPRuRHWsfBJ7iAwZE4fZGC/ l3fsT0PvL4SjsE49AnYsX1JiOi5gMeLe+nEvZK0AKBn+gx1GEp+8VJq2pHAGJjVqBS2n g/pasXB8FcgNvFReysZ8YVJQ91XHEnZEL9mnrSttJnjRKA9Kp5XDI+e6mYtqYk3/Wck0 0Zr6QDaU9O20NrnyZCccqQYHXVpQePtC9oAum1JpSCQCiwFUBTFV4TsznhIz0wLeQ2lb jXRBR1ntij6h0j4ZYa8UtmMX/Oeq5dRwpSZTEHh1NOusZmHE/L/1SH66/yKgK8PMFVNG vUdw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787094122; x=1787698922; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=jjfWQTULW6kpWj4uQcqe65fiA3Rop9X8RDu4HH8k3wc=; b=LjM53Eqxv2xGyGRUdRK6mN7OMp7sv+OYUQ0nJUjyA3HZSzjwiLSQFVERMSvuJXYdnr FHrO2+/1ZbOfbEtz3pA/9oOS6hg+QuL/x14axg30YcuXCqcRTWLH4+EX2qUrgNP00JrN IIjW9r0vzpUsoN/aN77u3cPTfhfJS4LK1rfcpazgG9pYi/YzGVjUawGfmaORDilIXHKJ Gr/B7nHtFRxvMRsc7hUV7AKlTjN61ttbD9B9gGInCYINcQi6k7oFG6L9SLL2AbDZJJHj glKRNioewadE5mGL2Dm6TA6397arcpLheHqq/E3HO/X5gA/+ghvaL3Ift/wIDWay9s+u pDUw== X-Forwarded-Encrypted: i=1; AHgh+Rq3F/Ejoa7Y/f3CIvK3r2DCpj30jV8wRlMHhr5tGG8EEo2H42V0476FDI5fECdeq/YmGXpnfvbUNwNTo8k=@vger.kernel.org X-Gm-Message-State: AOJu0YyA4RvYbpW/DEmp/vM7z3zCvJwtDQAT5Th3jOvHdTKyYmLwvmjl IfiajsJSdnA9ML5uEeIaNYTgWTwFvyvvsYqglhIcEe4tV7lHDjiJD6uL X-Gm-Gg: AR+sD13ceuIIWlarNun5l+7TrWRk+/PnegyiggPzzYUy/KMv1seCEpPTEAW/OMjfUv2 6VOto6RNSqZkXx9/bTt1bCTpy3wkDfIffaNRf3SfoALJv38d6eJw3MdRVFWeOT+BUpa58ni/XRr J9B++qy1yT7Qkh/c6AyqRd4W5XS7qIX+3jzYKKZrbD55Vzc3ZfqvODrhauMLgAw7NElXvBciNb7 /hw3F6mx7eTsDuAonaHHKP6vCbxnFIJLIjj8Z7f356B4qbT75JlarrlkIWg8BllfC+71QLbOHw6 SsCDb1V6qldiXR/jn7sqtnnuWYSoqmtkyAvt+cHHYs/foFpeaT0zhCMjYuKBUwtkHC9yMsyCI2P Vygkzo4ly1zlwT8oADtHv7v6NNVHWy51R8jGcD73DrD6A+e47o8+cwrwB3ccrqsxgbsOZtxFjyi 7xyU2X1lBSCPFB9QlyRppICJtP0w2J9rnjfkkLFbCpwbGHxi9RPzIcqWuWafItJgVMhVZA8KpsO ytTIFtd X-Received: by 2002:a17:902:f682:b0:2b2:67ca:5ff9 with SMTP id d9443c01a7336-2d5fd41d626mr5840475ad.0.1787094121673; Tue, 18 Aug 2026 16:02:01 -0700 (PDT) Received: from devvm16600.scu0.facebook.com ([2a03:2880:9ff:64::]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-327bef3bb51sm456874eec.6.2026.08.18.16.02.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Aug 2026 16:02:01 -0700 (PDT) Date: Tue, 18 Aug 2026 16:01:58 -0700 From: Ziyang Men To: Tejun Heo Cc: kernel-team@meta.com, Jens Axboe , Josef Bacik , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Shuah Khan , Johannes Weiner , Michal =?iso-8859-1?Q?Koutn=FD?= , Roman Gushchin , Shakeel Butt , JP Kobryn , Mykola Lysenko , linux-block@vger.kernel.org, bpf@vger.kernel.org, cgroups@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] block: add BPF kfuncs to read blkcg io.stat Message-ID: References: <20260817214205.723267-1-ziyang.meme@gmail.com> <20260817214205.723267-2-ziyang.meme@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: Hi Tejun, On Tue, Aug 18, 2026 at 12:42:54PM -1000, Tejun Heo wrote: >On Tue, Aug 18, 2026 at 03:31:29PM -0700, Ziyang Men wrote: >> Ok I will add the casts bpf_get_blkcg() and bpf_put_blkcg(), and remove the >> check of css->ss in above functoins. > >RCU_PROTECTED is probably better than get/put(). Yes we can make the blkcg* RCU_PROTECTED but then the bpf_blkcg_flush_stats() needs to take the @cgroup* since it is SLEEPABLE. Does this work for you? Best, Ziyang > >Thanks. > >-- >tejun