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 D1EB13101BC for ; Mon, 16 Feb 2026 14:23:11 +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=1771251796; cv=none; b=gBiMVU299HgIUC+KvgRoI/WZv4vaIW385oCYAKoMvWpAAdD34j5imDovaeGfPamr6ZNnVIF6igEv3zftf9/UK8KTpAL/TnLfJGOq1xTV+Q5CIkXp88Cwqx//92xpgKFqNI8h4LvBxX3l52XhVmKOPZboyNbqzveysvVSMvaaRAo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771251796; c=relaxed/simple; bh=y+UVZqqfsDj8r0qSEb984paPV5c0IUbaBniR4UoqvQY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Hb9/empEcVRH6Sb3UY39NYz18HCZ1FtVT9tnqgtOPW6AgIxbr8x0118nAZmdlcJwHgtHTadC4vGQnmS+JlQTGrT1pNlN8OB8jZRrcAoEHSLjm/99mWhgJev6mcZ5AYymLar0CtVel07xirkzmlo+ffBgB6Hrt5hZTuclHgUyidY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (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=jHsQp3d8; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (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="jHsQp3d8" 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=VjZspzWG+H0E9YOj5DSRiLsaeWdF6wIeH3nEZ2b5sNw=; b=jHsQp3d8DBzb5jm7ifkv/OZN4a sGgXPTqIE0ySv3ULEZCeuWMvy5h0yLvGhe73/RFofgAt3CArNHwIBugLdjRVQ4wEH3RZ4zxAoFYNJ SjJeEThhExQ79rfBQZcrk54F21LtPKW99MEa5dxnIT1INbpLrrK6c8DtgOxzesZKxkYL8NagFeYzR S4TqqCsCZc/4m3BjpS5My1dUzqJWqGYtdlQO+G8hi/5Ayh+VGdAVcK1Nk6XwuisASjYfy4bugRg++ P4oVwygHfMEe5TKZxeeGa3SzWsH51Az/e9e3rVzxz2L6GDbs1sPPZXpnJX/2bv4W8+rMweByDG9hZ S/mcKWbQ==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vrzV6-00000002YPL-0NHZ; Mon, 16 Feb 2026 14:23:00 +0000 Date: Mon, 16 Feb 2026 14:22:59 +0000 From: Matthew Wilcox To: Wenchao Hao Cc: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: Add AnonZero accounting for zero-filled anonymous pages Message-ID: References: <20260214084514.2842745-1-haowenchao22@gmail.com> 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-Disposition: inline In-Reply-To: <20260214084514.2842745-1-haowenchao22@gmail.com> On Sat, Feb 14, 2026 at 04:45:14PM +0800, Wenchao Hao wrote: > Add kernel command line option "count_zero_page" to track anonymous pages > have been allocated and mapped to userspace but zero-filled. > > This feature is mainly used to debug large folio mechanism, which > pre-allocates and map more pages than actually needed, leading to memory > waste from unaccessed pages. Why are you trying to get this upstream when you admitted in an earlier email this is just for your internal use? Why do you think that "unaccessed pages" are the only, or even the largest source of extra memory consumption? The vast majority of files are never mmaped. This just seems like a giant waste of time.