From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C208C77B72 for ; Wed, 12 Apr 2023 13:17:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230328AbjDLNRk (ORCPT ); Wed, 12 Apr 2023 09:17:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230397AbjDLNRa (ORCPT ); Wed, 12 Apr 2023 09:17:30 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6ABEF7D93; Wed, 12 Apr 2023 06:17:05 -0700 (PDT) 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=4VlHv/eebtSZNw6qu18EWYsd77UMuH83TrbZ82hi3l0=; b=wJABmqoHBB/1fbJ+CFk75TYDpj A2zXjfrZgJ++GI4OYOnjfDTS+OSmfq1uj9xYjZaSTVcKK0r6fSRhzj/WQ3bE/ET6bWUPDh+g39VMt KTElskCTjuo/Kvu27Qyyh6dxJvpvbPJPJmYNLjBowGg3WlAwxMdFG7YxSUcWGsAay1c9nqm1Vxn98 N8YZqBRqYRrVR/AcQx/wP8sRKwxULN94IM7yOiU2koGBo8LKIpqaTLBGZlXZF1RoOU7kLBFF7Rs7w gHWu7CB35+j4NH//ricdi3SsKdWQBcURwfXDHNkF1A1UmW9o6mnbzs+nW1c7uyEcHDE9TS0tou5+E 9GfhWBjQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pmaKv-006tS5-Kq; Wed, 12 Apr 2023 13:16:33 +0000 Date: Wed, 12 Apr 2023 14:16:33 +0100 From: Matthew Wilcox To: Hannes Reinecke Cc: "lsf-pc@lists.linux-foundation.org" , "linux-fsdevel@vger.kernel.org" , linux-mm@kvack.org, "linux-block@vger.kernel.org" Subject: Re: [LSF/MM/BPF TOPIC] Sunsetting buffer_heads Message-ID: References: <6ca617db-5370-7f06-8b4e-c9e10f2fa567@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6ca617db-5370-7f06-8b4e-c9e10f2fa567@suse.de> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Apr 12, 2023 at 12:18:29PM +0200, Hannes Reinecke wrote: > Ceterum censeo ... > > Having looked at implementing large blocksizes I constantly get bogged down > by buffer_heads and being as they are intricately linked into filesystems > and mm. > > And also everyone seems to have agreed to phase out buffer_heads eventually. > > So maybe it's time to start discussing exactly _how_ this could be done. > And LSF/MM seems to be the idea location for it. > > So far I've came across the following issues: > > - reading superblocks / bread(): maybe convert to ->read_folio() ? > - bh_lru and friends (maybe pointless once bread() has been converted) > - How to handle legacy filesystems still running on buffer_heads > > I'm sure this is an incomplete list, and I'm equally sure that several > people have their own ideas what should or need to be done. > > So this BOF will be about collecting these ideas and coming up with a design > how we can deprecated buffer_heads. Might be worth reviewing this thread: https://lore.kernel.org/linux-fsdevel/20230129044645.3cb2ayyxwxvxzhah@garbanzo/