From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 8 Oct 2008 01:20:59 +0200 From: Andi Kleen Subject: Re: [PATCH, v3] shmat: introduce flag SHM_MAP_NOT_FIXED Message-ID: <20081007232059.GU20740@one.firstfloor.org> References: <1223396117-8118-1-git-send-email-kirill@shutemov.name> <2f11576a0810070931k79eb72dfr838a96650563b93a@mail.gmail.com> <20081007211038.GQ20740@one.firstfloor.org> <20081008000518.13f48462@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081008000518.13f48462@lxorguk.ukuu.org.uk> Sender: owner-linux-mm@kvack.org Return-Path: To: Alan Cox Cc: Andi Kleen , KOSAKI Motohiro , "Kirill A. Shutemov" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ingo Molnar , Arjan van de Ven , Hugh Dickins , Ulrich Drepper , Andrew Morton List-ID: On Wed, Oct 08, 2008 at 12:05:18AM +0100, Alan Cox wrote: > On Tue, 7 Oct 2008 23:10:38 +0200 > Andi Kleen wrote: > > > > Sorry, no. > > > This description still doesn't explain why this interface is needed. > > > > > > The one of the points is this interface is used by another person or not. > > > You should explain how large this interface benefit has. > > > > > > Andi kleen explained this interface _can_ be used another one. > > > but nobody explain who use it actually. > > > > Anyone who doesn't want to use fixed addresses. > > Can use shm_open and mmap to get POSIX standard shm behaviour via a sane I don't think shm_open can attach to SYSV shared segments. Or are you proposing to add "sysvshmfs" to make that possible? > interface without adding more crap to the sys3 shm madness. > > Sorry this patch is completely bogus - introduce the user programs > involved to 1990s technology. As already listed in an earlier email, but here again: - There are legacy interfaces that cannot be really changed who use sysv shm (e.g. X shm and others -- just do a ipcs on your system) - An system call emulation as in qemu obviously has to implement the existing system call semantics. -Andi -- ak@linux.intel.com -- 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: email@kvack.org