From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1D9721FAC4E; Thu, 19 Jun 2025 09:11:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750324290; cv=none; b=tD3qCc1rnAZVYnRIly9t5/MbeSuHYL7PI/iX53XUKEDivEzGsAwuItRUE/luzowqNh2MJw5iHKEhHue4r/XW6ppGIH8Ae9672n4PzX24nJO7dDNsXYOYOCVebtFNRsBMDlMeOTSgl/pdp2Rsu9HO2NXWfl9BGrkA+kiWw0cV+KA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750324290; c=relaxed/simple; bh=id+4Obe9bYVtCSedihssbxztPpNf7tuDB/mRLWXQypM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NgoLrW0nZHBFP81BDuRLCde4W+qIV6tCHQfIHKjkyEsEnMi8gAL9fF31YlnAtwd3i9vIRYli/aR3ly+kRzzKPvcYH9llgrhZKADC/ynSPlHJNY+tB324X72PCStYHzbr/TnGJaaRJByBHB01r0Dt7zg0xViFCVVvxRuhiNbyvjE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=OfBQVq47; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="OfBQVq47" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=/freNvJTihapOdWiWbhhHfrSf90bbOLe8PP6624NwlE=; b=OfBQVq47aP/lu+UVT99qBe3Asp X1yZ6QQtYySfP88Pg2P1I7ylGurdZcTJKpI3+8gGjBEAKaDy/pN2glRavep/6Gy3Ttqog0qp2IGBe z9gnEaNmM9QKuaWyd/SQfSbuZfSbuiMDa7zCCx8nntINh9+2qnYzdGNWZ6EowbcmO+Cgl50rk1I7L TKDI0uHJBcXrm2M0B/71Tty/09QQjPr58SSrIcUAoLiSX3HUSalRMjDglLiSC1zomaNhdW8qIlMiA +oGD2MmFUJEorVDIOQDZ21iisGRer0jXavvjYgIRwGbg+n0lpfrPnz3cM+6M3alXonZbEROc7Q0Ak ut/o2bDw==; Received: from 2001-1c00-8d82-d000-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d82:d000:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1uSBIn-00000007zbt-3UYC; Thu, 19 Jun 2025 09:11:21 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 58196307FB7; Thu, 19 Jun 2025 11:11:21 +0200 (CEST) Date: Thu, 19 Jun 2025 11:11:21 +0200 From: Peter Zijlstra To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org, Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Ingo Molnar , Jiri Olsa , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton Subject: Re: [PATCH v10 06/14] unwind_user/deferred: Add deferred unwinding interface Message-ID: <20250619091121.GF1613200@noisy.programming.kicks-ass.net> References: <20250611005421.144238328@goodmis.org> <20250611010428.770214773@goodmis.org> <20250618184620.GT1613376@noisy.programming.kicks-ass.net> <20250618150915.3e811f4b@gandalf.local.home> <20250619075008.GU1613376@noisy.programming.kicks-ass.net> <20250619045659.390cc014@batman.local.home> Precedence: bulk X-Mailing-List: linux-trace-kernel@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: <20250619045659.390cc014@batman.local.home> On Thu, Jun 19, 2025 at 04:56:59AM -0400, Steven Rostedt wrote: > We have a many to many relationship here where a task_work doesn't work. > > That is, you can have a tracer that expects callbacks from several > tasks at the same time, as well as some of those tasks expect to send a > callback to different tracers. > > Later patches add a bitmask to every task that gets set to know which > trace to use. > > Since the number of tracers that can be called back is fixed to the > number of bits in long (for the bitmask), I can get rid of the link > list and make it into an array. That would make this easier. So something sketching this design decision might be useful. Perhaps a comment in the file itself? I feel much of this complication stems from the fact you're wanting to make this perhaps too generic.