From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f41.google.com (mail-wm1-f41.google.com [209.85.128.41]) (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 E15161A726B for ; Fri, 20 Dec 2024 09:04:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734685476; cv=none; b=qhq401rWEVOKi2PqUF2/28PFow0qS0qhUr+3/Om6UeOJAR0Tm5AWGllxye2z55zB3rd1TFKDbEOjAg4Zc0nCUZ0y5VcJLAG9u8Mh/SWrTGzHJKrgNqT7H9EyQt4/zlpkwZvnQfWkSSC+4/5nRebq7U+YoTvAjlGtokcKpdLqYs8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734685476; c=relaxed/simple; bh=2kJHVUKKKGg0H5zigtqYQdqHugZZj2MnjphIGJvYb8Y=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=Q7Crm8DOP1PNTbdcuMbMnHjD0mInKi2YBz2gjEFE/Xb1B/g6zeZCsGPX1sVKx6IiSB+PCTH845TBrNwPXyetpgKkL53pSsHFtfNCXzu29Fx7quyf7eIckRA6u3eqnl8K9eY33wqgxsS7LD+QeiMe45uv26T12zg059jbpEwYTCY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=xenomai.org; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.client-ip=209.85.128.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=xenomai.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-wm1-f41.google.com with SMTP id 5b1f17b1804b1-43634b570c1so11904465e9.0 for ; Fri, 20 Dec 2024 01:04:34 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1734685473; x=1735290273; h=mime-version:message-id:date:user-agent:references:in-reply-to :subject:cc:to:from:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=lqh/PbsHi7vwVJ6LRzgNU6xM1MY+HTjbDZLB2E0iFjo=; b=bRXrKrXDQJfXGdaQtasQusTepjViyiRqKYuj5Im4NcvMBcOu7LrO2wJTT/Lq0T66nZ rCFkPxoyKl7Gztt8BSNgPzexmfhBNy7mUWYcXR4LAj0hRAXqf4GqlL8JLKRk64eYq7ZZ wfkMIju0fFl6xoO4zkL6nu31Gq/PwxHLmDbgzpRDjJAgh/PYDRDUtGo0v5imI4VOwN91 fsPvV3+UMVsbk+k2CXs8GxlLy2VUZSbKOcjm9x/ptK4HIRkgm1UddveC327a0ZwSn/Fi wTHV6/6PZZgWekb9W8NdYUbEET8ozsfnLWkYax1nx72WDCGGJuugZVvymmJsT2a+i6at cRnA== X-Gm-Message-State: AOJu0YzPpyidXYJZdsUWDcXLGYH8/G9O7nU2d3oiuAZvPyRR00uJPz3E X+9QkogGAlio25i5Jg7lUcgWaXSJjYtSTl7XnXIjkt196i7GV+3nyOWb8A== X-Gm-Gg: ASbGnct37FoXdB5cr1niy7FCCbBHjQ0cifmvBvlKe3mCploqHSMzbQZleSYJG8pF/FA gfRuHJKXSTc14RZHIGrgGLH4CQaTq2nei1xDqYxpUYFJ01XGucOSv3BTjhKWxt2/jCZqfXLaMcW MmC/xb8kRUKaroEdavABBztF9Pznv5EfuiYzHiViq2uUpeMjN/TwRtQC/nn23soQLTarVEQmfFW pMfcoQM56KwevPoBgqmHkxRACHsi7DMEf+gMHJtag== X-Google-Smtp-Source: AGHT+IHLOWW/5KFVCwOhQ6WDB6BQXqa/loM0tGXQ59RZFyPHbg3XvI+mVuk+BvY4fp9NqRkVx+rtyA== X-Received: by 2002:a05:600c:450f:b0:434:fb65:ebbb with SMTP id 5b1f17b1804b1-436686461cbmr16726215e9.17.1734685472889; Fri, 20 Dec 2024 01:04:32 -0800 (PST) Received: from pyro ([2a01:e0a:19b:3cd0:989a:5c4b:b7ff:baf]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-436611fc762sm40126015e9.11.2024.12.20.01.04.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Dec 2024 01:04:32 -0800 (PST) From: Philippe Gerum To: Qichen Qiu Cc: xenomai@lists.linux.dev Subject: Re: [Draft RFC] Bring POSIX signal to evl In-Reply-To: (Qichen Qiu's message of "Fri, 20 Dec 2024 16:57:35 +0800") References: <20241218122615.1974864-1-ruiqurm@gmail.com> <87v7vf1xw2.fsf@xenomai.org> User-Agent: mu4e 1.12.1; emacs 29.4 Date: Fri, 20 Dec 2024 10:04:31 +0100 Message-ID: <87ldwa4teo.fsf@xenomai.org> Precedence: bulk X-Mailing-List: xenomai@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Qichen Qiu writes: > Hi. > Thanks for your suggestions. It is really helpful. > >> However, big CAVEAT: the EVL/x4 locking model is fine-grained like the >> one the regular kernel implements, unlike x3 which exhibits a single >> coarse 'superlock'. Porting will require to reconsider a significant >> portion of the original code under this new light. > > Do you mean the `nklock` that is used in almost every syscall? I wonder > what the original purpose of this lock is. Is that a global lock like the BKL? > Yes, this is a recursive single lock coming from the Dark Ages, which is basically used throughout the core to serialize access to almost all resources. This is why x3 does not scale that well SMP-wise. -- Philippe.