From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 A0DF846AA66 for ; Mon, 31 Aug 2026 17:16:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788196598; cv=none; b=EvhuLjGpuRIfCXqhna2GM4nHiC5FJofgIpaNaLi2yRSgH7HGTApoZ18kBDXJ+cjOaHcyipJPzmUc5RzcCeEmjMQTGmSjZck8PKTRc7N5D3BNfNxJimW+AIj/utt7hN+ywsT2/4XBiTXQzUkEj92Pi1wLfZ1f7TxyPXa8wNTA08c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788196598; c=relaxed/simple; bh=oHd9f35WxUkAueDFlsMLDEM/H0He6nONSuQ8dsUZGwg=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=PSa0LKKg9X5UWgzBZJV9Tc7xoLU2PGYZdunVlnP8Vj0GSqxTO6Pju6/DiERtTO9Ox+ntmnaef4Q+CA0nrgfbLjzzHBcIRyC8MuWeCbjnNiMRPcRbZu1QjcClC3Iz7RS14Wc9DpSm3Wg6kJrL/15X7Q5V8RzTGTqbmu2euRGQTjI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=EzzJsIrV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="EzzJsIrV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C7EC31F000E9; Mon, 31 Aug 2026 17:16:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1788196597; bh=kUaWdR9O4HzkDC+DSBrS4R/dmcOoGGm7UramsGCwQrU=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=EzzJsIrVgH3Wyi7L4/wU3Cyz6vEsvdK7ZdVuf3tlrOItrdEPGhti+wiObeuHCtMDw O7B4xl5+NNRTjhTwWoVZ+UG7Yh1v0a7jHtkkbI/wubyeWn6REdP9VZM4JHbSVfq9ga u7syyMwRhz82tT4Pr3td9WK77+mNTWWaDLHlKtGc= Date: Mon, 31 Aug 2026 10:16:36 -0700 From: Andrew Morton To: "Lorenzo Stoakes (ARM)" Cc: David Hildenbrand , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/vmpressure: remove window size TODO Message-Id: <20260831101636.a714f7171af108d520d4848c@linux-foundation.org> In-Reply-To: <20260831-remove-vmpressure-todo-v1-1-498515e59cdf@kernel.org> References: <20260831-remove-vmpressure-todo-v1-1-498515e59cdf@kernel.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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 Content-Transfer-Encoding: 7bit On Mon, 31 Aug 2026 14:42:11 +0100 "Lorenzo Stoakes (ARM)" wrote: > There has been a steady stream of patches that have been submitted by > newcomers to core mm 'fixing' this TODO, with all but the original having > very likely been generated by LLMs. > > It appears that TODOs to LLMs are like red rags to a bull. > > In addition, TODOs in code often bitrot and are distracting - those who > understand the code know what could be improved in future. > > Therefore remove the TODO. > > The work required to actually fix this TODO requires somebody who both has > understanding of the code and significant real-world data to back their > changes. > > Such a person doesn't require a TODO prompt to implement this change, so > nothing of value is being lost here. > > ... > > --- a/mm/vmpressure.c > +++ b/mm/vmpressure.c > @@ -30,9 +30,6 @@ > * > * As the vmscan reclaimer logic works with chunks which are multiple of > * SWAP_CLUSTER_MAX, it makes sense to use it for the window size as well. > - * > - * TODO: Make the window size depend on machine size, as we do for vmstat > - * thresholds. Currently we set it to 512 pages (2MB for 4KB pages). > */ > const unsigned long vmpressure_win = SWAP_CLUSTER_MAX * 16; otoh, we could enhance the TODO to explain these considerations. This might result in the LLM warriors submitting more usable work. It would be a strange place to socialize these things but as you said, red rags.