From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6F7B44C7C for ; Sun, 4 May 2025 06:16:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746339392; cv=none; b=O1mU3joGzXqFnoZTau72hdcxcQToTsKuadoWpmXWCLrkkHyhGr8jUb+gY5IkytnSb/YCvfmlbkxrLy/05uMoBqS+CkVuSY8HuApEEKyd/DFMhStUVOjEbG8iVSJIlTy2meFVYZ9Cgsh/Hd0sN7PshQ7ehFb9PGKIVFFSbBP3Ywo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746339392; c=relaxed/simple; bh=k1l3lNy8QfCozdRuWnbxpupvL+fhq9WSJ9NvFXGxJq8=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=IXGwYh8Bd75vmaSj1aSgxEDwjnVCJ+RPDqyhMSgpu6TJJBAJS4Dxrhi9va1ACSJAmWQqt5Hv28oPiMHxqkfaSuXMVMGtwwXBKnUZnSoR9Zy9Esp4DraYaKuugXBtyDkYz/bFRHrD65/nSVQ30qXfr7+A4+27ZuLfrWLRZtEF33M= 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=2k9SvRWB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="2k9SvRWB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8FFCEC4CEE7; Sun, 4 May 2025 06:16:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1746339391; bh=k1l3lNy8QfCozdRuWnbxpupvL+fhq9WSJ9NvFXGxJq8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=2k9SvRWBbM2BRHMN7c8f+QuhIb1OAA0knaO4TxcwABmvf6l42VkPoqxX5v/8NhBwo eBQULqcTmlmvmBITdkzaVfpNhnT/T3V6KfzlEF6iSZ3SxRc5aLg27m9NuVllwQun4O rJom5HkumeSbtOpG+Xqq3r2JxeeOgU5rp+31yHX0= Date: Sat, 3 May 2025 23:16:31 -0700 From: Andrew Morton To: Oscar Salvador Cc: David Hildenbrand , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Jonathan Cameron , Rakie Kim Subject: Re: [PATCH v3 0/3] Implement numa node notifier Message-Id: <20250503231631.7d8191e51e1d11569b529826@linux-foundation.org> In-Reply-To: References: <20250502083624.49849-1-osalvador@suse.de> <20250503200334.3f912eeb7ca484bca4eec7fd@linux-foundation.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 Sun, 4 May 2025 07:44:40 +0200 Oscar Salvador wrote: > On Sat, May 03, 2025 at 08:03:34PM -0700, Andrew Morton wrote: > > Why is this a problem? Is there some bug? Are these notifications so > > frequent that there are significant inefficiencies here? > > hi Andrew, > > There is no bug, it is just suboptimal. > > That the numa node state changes were tied to the memory notifier was > something hacky and that have us bugged for a while now. > Were mean to tidy that up but just never got around it. > > Actually, first time I brought that up was when I reviewed the first implementation > of memory demotion (~ca 3-4 years ago now?). > > With the addition of yet another consumer (auto-weitght mempolicy) that was only > interested in get notified on numa node changes, it became more clear that we > really want to split those up. OK, please add to the [0/N]. > > Further down-thread, Gregory tells us that Dan's patch "seems to fix > > the underlying problem", but nobody (including Dan) told us about any > > "problem" at all. > > That is related to auto-weight mempolicy patches, not to this one. > I _think_ Gregory means that I take it in as part of the series. Ah, I'm glad to have company in my confusion ;)