From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jes Sorensen Subject: Re: [PATCH] realtek: rtl8xxxu: Use const init arrays Date: Sat, 01 Oct 2016 16:32:17 -0400 Message-ID: References: <459bf15427d92cd052fb2fe080438fd97a8a6cd8.1475343483.git.joe@perches.com> <1475352058.1996.1.camel@perches.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Cc: Kalle Valo , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Joe Perches Return-path: In-Reply-To: <1475352058.1996.1.camel@perches.com> (Joe Perches's message of "Sat, 01 Oct 2016 13:00:58 -0700") Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Joe Perches writes: > On Sat, 2016-10-01 at 14:53 -0400, Jes Sorensen wrote: >> Joe Perches writes: >> > Make the init arrays const to reduce data. >> > $ size drivers/net/wireless/realtek/rtl8xxxu/built-in.o* >> > (allyesconfig: x86-32) >> >   text data bss dec hex filename >> >   80107 13651 58 93816 16e78 >> > drivers/net/wireless/realtek/rtl8xxxu/built-in.o.new >> >   65303 28435 58 93796 16e64 >> > drivers/net/wireless/realtek/rtl8xxxu/built-in.o.old >> In total you grow the kernel by 20 bytes. You reduce the data segment >> substantially while growing the text segment instead. > > No, not really. The alignment boundaries move a bit for > this particular compilation. It could go the other way for > a different compiler version or set of CONFIG options. > > What's important is multiple pages of .data move to .rodata. Your output shows it moving to the text segment - if it's in a different segment, eg. rodata, you should use output demonstrating that to justify the change. Jes