From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 BFDBA2D9780; Fri, 14 Nov 2025 20:06:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763150799; cv=none; b=Y1ZBp32yerfegZLLfojCvRdsovyoOc8A9V+SP5zPdt/jKENRXEevivHljmNQpN8eMiA2eC/uNWElK9i4CCfbVMNFTX8cNS94Lh1eZaV/XLdjJStVpfGxNmA0aJ6nqIB+YjE15v5fZtwtquuYHRyNN7DTeo1rR5ngvOEH1YxTuaw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763150799; c=relaxed/simple; bh=TIDmqQudIf68egjfbjX/UD1YyPYjDAPME3UzGD537xw=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=szcw/NSupN6GUcignlwU+iokAdXyDQ5uOWC1sO79o/6a4PTuLQVftZDRpR/PPCFBxXP21Za7NjN44RNu4ONZzCft3wYwzObx1OSyy8vYMBvcLq0rlH3a/cLisFZDYh+KfnRDOP/s4esQh7KivB3vcWnHlUpJdEBA/dKdIhGoG3k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=YK9eEZEa; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=1Zyc6PyP; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="YK9eEZEa"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="1Zyc6PyP" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1763150795; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=JOqB4C/lS20t6tPC5FIrQm+ReT0eGwkkWKV6KUVlY+c=; b=YK9eEZEalWaKmf+x8aV4nBEexkqfsmiKreG3Y2jkPgAgLWTY9R8IBAqeSpkzvcfTlK/5vT +O81wGsZ0UIeJ5jBhUw4Eoayfv/X/R8/YAkUQfbLySwBD+nR9giKh2lTUX2IuXR2sbXviX FoDaeDfQYEVnADDuXPIQ/3NYR3mHOmWH0metLgocPmrm5KlONkA2MI+xuHLeh3MThztb1A kXnDdCaO2sDMKHkhrx9itHQBX0xVNdyadNovuurLFgsetAEAqd8BZzCxmcKF/5SsAQ1SuC 9Fvj3cEHnJH7K5iz+x8gAJ7PDgm0830h9iPB4luicMqudfO8UPSUoF00Q35K7Q== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1763150795; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=JOqB4C/lS20t6tPC5FIrQm+ReT0eGwkkWKV6KUVlY+c=; b=1Zyc6PyPyhUajFuS2x9XsSMHMGTgSzQMRTnNoHUVo4zlrqPxJr60WPV70Jazg4G37kJhwh jOcgXkNRpr6vopAw== To: Andy Lutomirski , "Paul E. McKenney" Cc: Valentin Schneider , Linux Kernel Mailing List , linux-mm@kvack.org, rcu@vger.kernel.org, the arch/x86 maintainers , linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , "Peter Zijlstra (Intel)" , Arnaldo Carvalho de Melo , Josh Poimboeuf , Paolo Bonzini , Arnd Bergmann , Frederic Weisbecker , Jason Baron , Steven Rostedt , Ard Biesheuvel , Sami Tolvanen , "David S. Miller" , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Mathieu Desnoyers , Mel Gorman , Andrew Morton , Masahiro Yamada , Han Shen , Rik van Riel , Jann Horn , Dan Carpenter , Oleg Nesterov , Juri Lelli , Clark Williams , Yair Podemsky , Marcelo Tosatti , Daniel Wagner , Petr Tesarik , Shrikanth Hegde Subject: Re: [PATCH v7 00/31] context_tracking,x86: Defer some IPIs until a user->kernel transition In-Reply-To: <1a911310-4ca5-45a4-b9bf-5f37c6ab238e@app.fastmail.com> References: <20251114150133.1056710-1-vschneid@redhat.com> <89398bdf-4dad-4976-8eb9-1e86032c8794@paulmck-laptop> <1a911310-4ca5-45a4-b9bf-5f37c6ab238e@app.fastmail.com> Date: Fri, 14 Nov 2025 21:06:34 +0100 Message-ID: <87zf8o9y5x.ffs@tglx> Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Fri, Nov 14 2025 at 10:45, Andy Lutomirski wrote: > But I did that test on a machine that would absolutely benefit from > the IPI suppression that the OP is talking about here, and I think it > would be really quite nice if a default distro kernel with a more or > less default distribution could be easily convinced to run a user > thread without interrupting it. It's a little bit had that NO_HZ_FULL > is still an exotic non-default thing, IMO. Feel free to help with getting it over the finish line. Feeling sad/bad (or whatever you wanted to say with 'had') does not change anything as you should know :) Thanks, tglx