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 X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70E83C433FF for ; Fri, 2 Aug 2019 07:56:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4040F2086A for ; Fri, 2 Aug 2019 07:56:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="AroLgI03" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390550AbfHBH4T (ORCPT ); Fri, 2 Aug 2019 03:56:19 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:58086 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390522AbfHBH4T (ORCPT ); Fri, 2 Aug 2019 03:56:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=F/U4RF9BWHk0NEnwlESdSBl0fNvIrEH3x91nEkfBj0s=; b=AroLgI03kPrunxjAUUNLPYV1H3 TY2FcCliV84FPetqGsDrGQIB1YHeGEtq136f9fHRgArJ1FZB3u6MuN1yZp9ss2fNLJgleH4V+G6w6 h2N3lXQJ5Zjc2kZ7cInHAA4AXzk+GbX4y6qd9hMLl9NVYJ+hJygShEumgsQZ3rQrGiolVnClyvdTe eEsZwhFKQQ1aJgb8rPmz+kKfko+6kIJKf8u47ByPJh9hwk7PkAn72aLooNLKhm6pnJk/16lxyl/xR QEszcatR8lr7FGMsFu32CkCbOEKQ1OuJdTpMXcxM9ibcjNxuHzCy1JlMsZubGrSR8aHsjqENeCTjT UcsThg4w==; Received: from hch by bombadil.infradead.org with local (Exim 4.92 #3 (Red Hat Linux)) id 1htSQ8-0006iu-RB; Fri, 02 Aug 2019 07:56:12 +0000 Date: Fri, 2 Aug 2019 00:56:12 -0700 From: Christoph Hellwig To: Thomas Gleixner Cc: LKML , Peter Zijlstra , Ingo Molnar , Sebastian Siewior , Anna-Maria Gleixner , Steven Rostedt , Julia Cartwright , Jan Kara , Theodore Tso , Matthew Wilcox , Alexander Viro , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, Jan Kara , Mark Fasheh , Joseph Qi , Joel Becker Subject: Re: [patch V2 0/7] fs: Substitute bit-spinlocks for PREEMPT_RT and debugging Message-ID: <20190802075612.GA20962@infradead.org> References: <20190801010126.245731659@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190801010126.245731659@linutronix.de> User-Agent: Mutt/1.11.4 (2019-03-13) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hi Thomas, did you look into killing bіt spinlocks as a public API instead? The main users seems to be buffer heads, which are so bloated that an extra spinlock doesn't really matter anyway. The list_bl and rhashtable uses kinda make sense to be, but they are pretty nicely abstracted away anyway. The remaining users look pretty questionable to start with.