From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 14 Jul 2007 08:25:37 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 3/7] Generic Virtual Memmap support for SPARSEMEM Message-Id: <20070714082537.b854b69e.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20070713235121.538ddcaf.kamezawa.hiroyu@jp.fujitsu.com> <20070714081210.1440db40.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: apw@shadowen.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, npiggin@suse.de, mel@csn.ul.ie List-ID: On Fri, 13 Jul 2007 16:17:32 -0700 (PDT) Christoph Lameter wrote: > > Note > > >From memory hotplug development/enhancement view, I have following thinking now. > > > > 1. memmap's section is *not* aligned to "big page size". We have to take care > > of this at adding support for memory_hotplug/unplug. > > You can call the functions for virtual memmap allocation directly. They > are already generic and will call the page allocator instead of the > bootmem allocator if the system is already. They will give you the > properly aligned memory. Perhaps you can just change a few lines > in sparse_add_one_section to call the vmemmap functions instead? > yes, I think so now. But we'll see warnings of "section mismatch". Because this patch includes following. == func() { if() call_generic_func else call_boot_func. } == > > 2. With an appropriate patch, we can allocate new section's memmap from > > itself. This will reduce possibility of memory hotplug failure becasue of > > large size kmalloc/vmalloc. And it guarantees locality of memmap. > > But maybe need some amount of work for implementing this in clean way. > > This will depend on vmemmap. > > That is a good idea. Maybe do the simple approach first and then the other > one? Yes, simple first. Above one will be an option for people who use big-section-size, like ia64. -Kame -- 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