From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yuri Tikhonov Subject: Re[2]: [PATCH 01/11] async_tx: don't use src_list argument of async_xor() for dma addresses Date: Tue, 9 Dec 2008 03:41:36 +0300 Message-ID: <1195158776.20081209034136@emcraft.com> References: <200812090055.26721.yur@emcraft.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Dan Williams Cc: linux-raid@vger.kernel.org, linuxppc-dev@ozlabs.org, dzu@denx.de, wd@denx.de, yanok@emcraft.com List-Id: linux-raid.ids On Tuesday, December 9, 2008 you wrote: > On Mon, Dec 8, 2008 at 2:55 PM, Yuri Tikhonov wrote: >> Using src_list argument of async_xor() as a storage for dma addresses >> implies sizeof(dma_addr_t) <= sizeof(struct page *) restriction which is >> not always true (e.g. ppc440spe). >> > ppc440spe runs with CONFIG_PHYS_64BIT? Yep. It uses 36-bit addressing, so this CONFIG is turned on. > If we do this then we need to also change md to limit the number of > allowed disks based on the kernel stack size. Because with 256 disks > a 4K stack can be consumed by one call to async_pq ((256 sources in > raid5.c + 256 sources async_pq.c) * 8 bytes per source on 64-bit). On ppc440spe we have 8KB stack, so the things are not worse than on 32-bit archs with 4KB stack. Thus, I guess no changes to md are required because of this patch. Right? Regards, Yuri -- Yuri Tikhonov, Senior Software Engineer Emcraft Systems, www.emcraft.com