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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 37554C3A5A3 for ; Fri, 30 Aug 2019 06:38:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0466A21726 for ; Fri, 30 Aug 2019 06:38:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567147136; bh=yLlZhjwSi0FuvKlMUG546ftoSzWKYZ+7uxnKbjaNlfI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=2tb/b3iafFjDEBvryW/MP1AIwaZkcPONSREmDpV+3MKn0loDGIfl1hxp0kBrQlPre SHWrz2Sf5StEFvXG4HJrk/lRz93cLpwoqqMwx8NaC0z4M9oR2k3VqNEGrN6uWkcflB 1Sc9tgd7zyPhyn59GYJHfUeNyM7PKPPjcBt1F5Ww= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727958AbfH3Giy (ORCPT ); Fri, 30 Aug 2019 02:38:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:36800 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726452AbfH3Giy (ORCPT ); Fri, 30 Aug 2019 02:38:54 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3110021726; Fri, 30 Aug 2019 06:38:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567147133; bh=yLlZhjwSi0FuvKlMUG546ftoSzWKYZ+7uxnKbjaNlfI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gCLt8q9o1tBPTkQHLIpPKFInXPSt4tlS2vG+4/nt9o65BUHDqNCVq3b/GF9BlIsRI wJlYFi8va6vbi4MLzR7ScDuUvYQQIvwX7VTL1MxtB6ETuEux3FCySErPdjCWB3GzL5 WgkC2sDv8eNi9OTb3fAwcO0RmgNyLkzKmrTCH+gw= Date: Fri, 30 Aug 2019 08:38:51 +0200 From: Greg KH To: Christian Brauner Cc: Joel Fernandes , Peikan Tsai , arve@android.com, tkjos@android.com, maco@android.com, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] binder: Use kmem_cache for binder_thread Message-ID: <20190830063851.GG15257@kroah.com> References: <20190829054953.GA18328@mark-All-Series> <20190829064229.GA30423@kroah.com> <20190829135359.GB63638@google.com> <20190829152721.ttsyfwaeygmwmcu7@wittgenstein> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190829152721.ttsyfwaeygmwmcu7@wittgenstein> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 29, 2019 at 05:27:22PM +0200, Christian Brauner wrote: > On Thu, Aug 29, 2019 at 09:53:59AM -0400, Joel Fernandes wrote: > > On Thu, Aug 29, 2019 at 08:42:29AM +0200, Greg KH wrote: > > > On Thu, Aug 29, 2019 at 01:49:53PM +0800, Peikan Tsai wrote: > > [snip] > > > > The allocated size for each binder_thread is 512 bytes by kzalloc. > > > > Because the size of binder_thread is fixed and it's only 304 bytes. > > > > It will save 208 bytes per binder_thread when use create a kmem_cache > > > > for the binder_thread. > > > > > > Are you _sure_ it really will save that much memory? You want to do > > > allocations based on a nice alignment for lots of good reasons, > > > especially for something that needs quick accesses. > > > > Alignment can be done for slab allocations, kmem_cache_create() takes an > > align argument. I am not sure what the default alignment of objects is > > though (probably no default alignment). What is an optimal alignment in your > > view? > > Probably SLAB_HWCACHE_ALIGN would make most sense. This isn't memory accessing hardware, so I don't think it would, right? Anyway, some actual performance tests need to be run to see if any of this make any difference at all please... thanks, greg k-h > > > > > > Did you test your change on a system that relies on binder and find any > > > speed improvement or decrease, and any actual memory savings? > > > > > > If so, can you post your results? > > > > That's certainly worth it and I thought of asking for the same, but spoke too > > soon! > > Yeah, it'd be interesting to see what difference this actually makes. > > Christian