From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <20050113212912.93033.qmail@web14308.mail.yahoo.com> Date: Thu, 13 Jan 2005 13:29:12 -0800 (PST) From: Kanoj Sarcar Subject: Re: smp_rmb in mm/memory.c in 2.6.10 In-Reply-To: <20050113210624.GG20738@wotan.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org Return-Path: To: Andi Kleen Cc: William Lee Irwin III , linux-mm@kvack.org List-ID: --- Andi Kleen wrote: > > In include/asm-i386/spinlock.h, spin_unlock_string > has > > a "xchgb" (in case its required). That should be > > enough of a barrier for the hardware, no? > > It is, but only for broken PPros or OOSTORE system > (currently only VIA C3). For kernels compiled for > non broken CPUs > there isn't any kind of barrier. > > -Andi Okay, I think I see what you and wli meant. But the assumption that spin_lock will order memory operations is still correct, right? Going back to what I meant in the first place, the memory.c code is doing something like 1. read truncate_count, 2. invoke nopage, which will probably get locks, which will ensure the read of truncate_count is complete, right? So, the original point that smp_rmb() is not required (at least in the position it currently is in) still holds, correct? Thanks. Kanoj __________________________________ Do you Yahoo!? Take Yahoo! Mail with you! Get it on your mobile phone. http://mobile.yahoo.com/maildemo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org