From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f45.google.com (mail-wm1-f45.google.com [209.85.128.45]) (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 EF016215776 for ; Thu, 12 Dec 2024 15:21:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734016893; cv=none; b=S6HnWtKPom4qmn4Os8cFmpRqLuDWr7Cm7EyZj02T5Rl92n4RSbudoqrxSQ8jSx5Dh6vTNSWyVYy+JjEkklmDAiJoRGpaaC0jFtn2z478DSLNUjIzN9Ih0vshrNevLqg3CWx2/W3IT4GyUdf6BPjuge/n5eTSISkb5X6eEk8w3Xk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734016893; c=relaxed/simple; bh=bk3STfDAAv/V3LnY1I/AoedPy1flrRGJGjRU8Fp+hNQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=a+dSj0OD/dO73T4Wo+FPSapY9eyYdeNKLwUz3AwhZKGR15K3FdK29qQkkvRTYxCJSxR2N+AXCMwYX+kMmZTHVp2frzGHp8ZbxTqhkStnOmyX3EChueccrMy+0Zyy22n5yYQWpvZGIQQvuDi4FDMl5RBVVYDK4foD1bIh01M1c5o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=GAufUW/u; arc=none smtp.client-ip=209.85.128.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="GAufUW/u" Received: by mail-wm1-f45.google.com with SMTP id 5b1f17b1804b1-434e69857d9so4845935e9.0 for ; Thu, 12 Dec 2024 07:21:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1734016889; x=1734621689; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=mZgbeOMR0zgVvnSYvzJKoDi9Utjk6AdxNEMQzQ7gxDs=; b=GAufUW/uacyakM5kgsJeCoR36HcN6UU0R4KzAceFV2jlCgKpEZ4dkFxIrux5JGpww4 fmOnveafciQeWdNJjyoFebucG7/zLtksjf+4Gg2gPzwkYLFEX1LL3GF2QS0Tk3sBUagO MF+9LeXYJ1tx2DTNhwoOQEP3+gHxQ6n6lS1TIXzjLsaVF6CWTdoSHUpv6mcu7Uo4WG2x R5XzAlQxIw0GkN7ruHcZOw5NndbhbGpV+I3Gx9T+0Q/KByyzSOisCk5MOf10IxrmITPR BmjPsSh2ykn94nQza82WgAO7WS6ZYESLFsxLnuHE0ywinc6gqV9gWDFQENARHNNXGeYQ PIww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1734016889; x=1734621689; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=mZgbeOMR0zgVvnSYvzJKoDi9Utjk6AdxNEMQzQ7gxDs=; b=VUd4Vu2ch7CA7xma3g7biQT1heLkhwqMW5wltM/pmvorGXzAvWp5+JBspJ8H56hXTP z3e31h93vjxz0KJdi0SCACcxkDJIXd2nOBv83cSNptS2PBIjQiNAmzzJhv07jSE33HTT 2yE3GTOaxHgcI1F3nmmVb9G3e3xhIwYWdeldfAbLfULGoRSW3G8sLJRQukZNZMGDvOgA nHtgBBMoWfQGZLCiqEANuWXZ/ClbjHOqTL5M22elBnE+FIvjtgMizZ5nnS3oPyuyLP/v KYFQgI/+YzPMzv0uSlJsDprBeLCm+3e04MWgudiG6jgaFFiCZP3uaNdGNzIRGcIbLNSD mAsg== X-Forwarded-Encrypted: i=1; AJvYcCXqxJJOYcIEFKSY5kA5tCfUDDbX4orrDxtrA1za/2Mq41SKKKnJXQOrqvv/XgXqyDM3VZM=@vger.kernel.org X-Gm-Message-State: AOJu0Yyj7oESDOuXhnSy+0TevPYzmJuLGAZ6OKXf7nlEYj7yzMr/n9H5 H3Vj1lMr9wSaxg+KNXMEIMCmS2r2WVTPyKdn1VeHxaYeHWVe94wDOlraKjXbGYI= X-Gm-Gg: ASbGncvOIOL5GQGpKoTb6XdqmuQWDP7mrrkzxhBJVfFRb/Ol1Rc6cli7VrFjIog9RGb wZud8tMrFBoJ55TW+0xzOI1LgfxEwo+T/2qbVJ4mMevQq5dAUsayancLJGUaxunuwCuPl9bkEnb LYK8ofQOfGnbhnS1MyJ090JinEmfEwWlX49o4AP6EeF9yLxlZcnZ72nFtnQmBGF4QYtPAQ1X2O6 PrjGIVbbQ6T4c0EF+NzBRbtj8OHxJ08HwlbdJSrVntTX58= X-Google-Smtp-Source: AGHT+IHZ8ARVzgG1bVH56SzNqfVZv1llTYjjlv2rUxxfSg8wKw0wG2wIDftVgfeTx4Rcd8jElw47Rg== X-Received: by 2002:a05:600d:1:b0:434:9f90:2583 with SMTP id 5b1f17b1804b1-436230e9734mr29316715e9.11.1734016889213; Thu, 12 Dec 2024 07:21:29 -0800 (PST) Received: from localhost ([193.86.92.181]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-436255531dasm19430415e9.8.2024.12.12.07.21.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Dec 2024 07:21:28 -0800 (PST) Date: Thu, 12 Dec 2024 16:21:28 +0100 From: Michal Hocko To: Sebastian Sewior Cc: Alexei Starovoitov , Matthew Wilcox , bpf , Andrii Nakryiko , Kumar Kartikeya Dwivedi , Andrew Morton , Peter Zijlstra , Vlastimil Babka , Steven Rostedt , Hou Tao , Johannes Weiner , shakeel.butt@linux.dev, Thomas Gleixner , Tejun Heo , linux-mm , Kernel Team Subject: Re: [PATCH bpf-next v2 1/6] mm, bpf: Introduce __GFP_TRYLOCK for opportunistic page allocation Message-ID: References: <20241210023936.46871-1-alexei.starovoitov@gmail.com> <20241210023936.46871-2-alexei.starovoitov@gmail.com> <20241212150744.dVyycFUJ@linutronix.de> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241212150744.dVyycFUJ@linutronix.de> On Thu 12-12-24 16:07:44, Sebastian Sewior wrote: > But since I see in_nmi(). You can't trylock from NMI on RT. The trylock > part is easy but unlock might need to acquire rt_mutex_base::wait_lock > and worst case is to wake a waiter via wake_up_process(). Ohh, I didn't realize that. So try_lock would only be safe on raw_spin_lock right? -- Michal Hocko SUSE Labs