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 C2175139B for ; Wed, 26 Feb 2025 04:33:41 +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=1740544423; cv=none; b=Lbo+E4JO8sZ60v8YUab71FT4v/rizj53Ys8IZOfMgoE6qk/LtVubffSwwSRK5HJFAP5TfqKXxGqxzu/mPp5HGjdV7ocQsXGxbiaif4l8MMI/hmzNl8oRzPuDO5ZP5Xn5fwDawjxUFTWoqDxtoazxeqXyufpWgQuWvH/JhMpKkB4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740544423; c=relaxed/simple; bh=IDapue4rgTIHsJRfPyjp6GQOVZoayFSYUIy5uwkhrmA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Hg+fF++UG/hFFBZCkjVe5HFDkV76kiVRIiSK7PjOpU+2gPZqXZfuHCGkgUpdC+ZufhboymYN1g6FBFO2Co2RJXyX6A1T5jR7mFZRjZGRfnTpIu+7zvVaj46Niv7X+mSQ5D5Z35fRYxpaEq+NcnXZ4i11+4+9hchqI5ep54dpm6c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (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=UWD2XSlX; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (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="UWD2XSlX" 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=+KLbcYrvhMSN5Ij7Rj7RwdB9a/HcqptQek/8PecY/CU=; b=UWD2XSlXXTxTwiElr3KhS8H3jo MyytzWebjkStTuSb+vINfEBKphabHnmbKjfexxnqfCNowfYORn4xrMIJ4SBo9Z+YWWTXYpNHVfI1i KoHE1oAMmXC8M9dDbXzJs7FgUHKTC5bxDkMkcj25p1zDI9fXOjaoGpJAqHPUEJuAWJJG/FgBX3YTg 9PdfdceGa2dOzjdVhVwlvHa6zN2tAcxuBpJ+qD0nwAfvNH10wH41lsfvnq2HMJPfVWa1VMAtoGl9g ilzvgfFHwY1Rlr+rMC076WNKVaJaJk/7qv4I5bogopG6TTk3otPRP6lWXegWL+A+K7WyZb1EWM960 FTMSpQjA==; Received: from willy by casper.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tn975-0000000Ds4Z-2Paq; Wed, 26 Feb 2025 04:33:39 +0000 Date: Wed, 26 Feb 2025 04:33:39 +0000 From: Matthew Wilcox To: Wei Yang Cc: Andrew Morton , mm-commits@vger.kernel.org, michel@lespinasse.org Subject: Re: + lib-interval_tree-skip-the-check-before-go-to-the-right-subtree.patch added to mm-nonmm-unstable branch Message-ID: References: <20250225042234.AC256C4CEDD@smtp.kernel.org> <20250226022233.wjvxv2o6672vhkky@master> Precedence: bulk X-Mailing-List: mm-commits@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: <20250226022233.wjvxv2o6672vhkky@master> On Wed, Feb 26, 2025 at 02:22:33AM +0000, Wei Yang wrote: > On Tue, Feb 25, 2025 at 12:35:29PM +0000, Matthew Wilcox wrote: > >On Mon, Feb 24, 2025 at 08:22:34PM -0800, Andrew Morton wrote: > >> The patch titled > >> Subject: lib/interval_tree: skip the check before go to the right subtree > >> has been added to the -mm mm-nonmm-unstable branch. Its filename is > >> lib-interval_tree-skip-the-check-before-go-to-the-right-subtree.patch > > > >I don't think this patch should be added. There's no claim of any > >performance win. Wei has a long history of tweaky little patches that > >may or may not be buggy. The interval tree has been around a long time > >and doesn't have a test suite. This feels like unnecessary risk. > > Your concern is understandable. A change in fundamental data structure should > be very careful. But I thought we don't take things personal. This isn't personal. It's noting your history. If you want to add a test suite for the interval tree to the kernel, that would be a useful set of patches. And it would remove my concern if we can demonstrate that we've exercised the code paths that you're modifying and everything is fine.