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 69099352022 for ; Tue, 11 Aug 2026 20:31:18 +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=1786480280; cv=none; b=VY//0Eizzk3palZRrtgltlzY3A3EhGLp4KjD9edS87mgGfnZZg6l0D2wvQ8taMtdRSSHo0j+c6b+5iKEd9Zzi7dQqLgtp7L9+rrG2D1zikMu+7Wf9UE9PVOD5S0mfKGB40wD3XXcB8O+Th0+GBDWZAOdrh1UBWw8t8+mvVsKyNA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786480280; c=relaxed/simple; bh=mEkooDKOXUdTEAl5Ykbhr6VrQFKcuWk3wXgrbjGbUnA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=B+Y+Lbq0bZNnXKyfKi7iiXeFaX2Zxa5eGATNwMBtSjDSGuw+bVjjb8eedb7AXZXQaPqcdjI0UovN1QjNAVcAqoLogcJAqT5Yuj7ZFQmalA5nwDQzIbiK1d7ursXCZG7yTyZv1QF4wbAEVfEC723EbVPsdR09hy5CaCvpqLqmzWc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=oSMWAXud; 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=pass 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="oSMWAXud" 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=PMnGCLWhe15ZxMrHk/gFLLP8e7MuOyBy5Hyx6UW6LII=; b=oSMWAXudvzm/CUEbGg26vfaXAT 8scbrwj0Ih+wvZNs6x47kHqDnjAC69dPHEpj8n3+gqisIxGsDyEYOh9g0bqDYd2MW/gnKZ5cCgMzZ zM2ewSjGoV5PVLorqk3cEgkPF2AEvbUhXOOfmMF4O1kS6Cta8embqZm3n/GywkrrOmmj1EDmSiy6o ooOg0NzBqxHIgkPM/M7KtMU3T+Ff94Mr7ltk9fi5xLzbq8qeBqMr2h+C4/kSZzUk0mOdc97jjTgyx 7pzvKxTjCSw3O5IQUCcjd2+lM7z4PxJ+ue0JuoxYQOMdzHTsr0GUWBmfmew7bejv5uOHpLUB6keWh Gb3HYFHA==; Received: from willy by casper.infradead.org with local (Exim 4.99.1 #2 (Red Hat Linux)) id 1wtt7h-00000000yJl-3DjL; Tue, 11 Aug 2026 20:30:58 +0000 Date: Tue, 11 Aug 2026 21:30:57 +0100 From: Matthew Wilcox To: Tal Zussman Cc: Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Youngjun Park , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Christoph Hellwig , Johannes Weiner , Yosry Ahmed , Chengming Zhou , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/6] mm/page_io: rename bio_associate_blkg_from_page() Message-ID: References: <20260806-b4-page_io-folios-v1-0-0899bac3b826@columbia.edu> <20260806-b4-page_io-folios-v1-4-0899bac3b826@columbia.edu> <612ed1ce-e7a7-410e-9ad7-256e77bc867c@columbia.edu> 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: <612ed1ce-e7a7-410e-9ad7-256e77bc867c@columbia.edu> On Fri, Aug 07, 2026 at 10:30:22PM +0300, Tal Zussman wrote: > On 8/7/26 2:56 PM, Matthew Wilcox wrote: > > It's s shame this isn't const-qualified (after all, we don't modify the folio). > > That needs folio_memcg_charged() to take a const folio pointer, which it > > could. And folio_memcg_blkg_css() and folio_memcg(). That's a followup > > patch though. > > > > I had the same thought when looking at this and went all the way down the > callchain to dump_page(). I didn't want to flood the list with patches, but > happy to send a couple follow-up patches once this is in mm-new. As the person who did the dump_page() const-qualification ... you're welcome ;-) (preliminary work in 2021 with 5f7dadf3958f and some preceding patches, then the actual constification in 2024 with 29cfe7556bfd and some precedig patches)