From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Schmitz Subject: Re: [patch] m68k, mm: set all online nodes in N_NORMAL_MEMORY Date: Sun, 24 Apr 2011 16:01:30 +1200 Message-ID: <4DB3A09A.70308@gmail.com> References: <1303317178.2587.30.camel@mulgrave.site> <20110421220351.9180.A69D9226@jp.fujitsu.com> <4DB3840F.3060503@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: KOSAKI Motohiro Cc: Michael Schmitz , David Rientjes , Geert Uytterhoeven , Andrew Morton , Roman Zippel , linux-m68k@vger.kernel.org, linux-kernel@vger.kernel.org, schwab@linux-m68k.org, "tg@mirbsd.de >> Thorsten Glaser" List-Id: linux-m68k@vger.kernel.org KOSAKI Motohiro wrote: > 2011/4/24 Michael Schmitz : > >> David Rientjes wrote: >> >>> For m68k, N_NORMAL_MEMORY represents all nodes that have present memory >>> since it does not support HIGHMEM. This patch sets the bit at the time the >>> node is brought online. >>> >>> If N_NORMAL_MEMORY is not accurate, slub may encounter errors since it >>> uses this nodemask to setup per-cache kmem_cache_node data structures. >>> >>> Signed-off-by: David Rientjes >>> --- >>> arch/m68k/mm/init_mm.c | 2 ++ >>> 1 files changed, 2 insertions(+), 0 deletions(-) >>> >>> diff --git a/arch/m68k/mm/init_mm.c b/arch/m68k/mm/init_mm.c >>> --- a/arch/m68k/mm/init_mm.c >>> +++ b/arch/m68k/mm/init_mm.c >>> @@ -59,6 +59,8 @@ void __init m68k_setup_node(int node) >>> } >>> #endif >>> pg_data_map[node].bdata = bootmem_node_data + node; >>> + if (node_present_pages(node)) >>> + node_set_state(node, N_NORMAL_MEMORY); >>> node_set_online(node); >>> } >>> >>> >> As Andreas pointed out, node_present_pages is set in free_area_init_node >> which only gets called at the very end of m68k mm paging_init. >> >> The correct patch would be something like this - the need for the >> conditional is perhaps debatable, seeing as we set the pages present just >> before node_set_state. >> >> Tested on my ARAnyM test setup so far. I'd like to wait for an independent >> kernel image built by Thorsten before I test on the actual hardware. Sorry >> but you'll have to restart your build Thorsten :-) >> >> Signed-off-by: Michael Schmitz >> -- >> diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c >> index 02b7a03..b806c19 100644 >> --- a/arch/m68k/mm/motorola.c >> +++ b/arch/m68k/mm/motorola.c >> @@ -300,6 +300,8 @@ void __init paging_init(void) >> zones_size[ZONE_DMA] = m68k_memory[i].size >> PAGE_SHIFT; >> free_area_init_node(i, zones_size, >> m68k_memory[i].addr >> PAGE_SHIFT, NULL); >> + if (node_present_pages(i)) >> + node_set_state(i, N_NORMAL_MEMORY); >> } >> } >> > > I think you are right. however I doubt m68k need to care memoryless node check. > probably following patch just work. > > ------------------------------------ > diff --git a/arch/m68k/mm/init_mm.c b/arch/m68k/mm/init_mm.c > --- a/arch/m68k/mm/init_mm.c > +++ b/arch/m68k/mm/init_mm.c > @@ -59,6 +59,8 @@ void __init m68k_setup_node(int node) > } > #endif > pg_data_map[node].bdata = bootmem_node_data + node; > node_set_online(node); > + node_set_state(node, N_NORMAL_MEMORY); > It does in fact - that's what I had as a workaround before. Memory node information is provided by the respective m68k bootstrap so memoryless nodes won't be possible indeed. > Maybe, the correct solution is to use CONFIG_ARCH_POPULATES_NODE_MAP feature. > the usage is simple, adding add_active_range() and replacing > free_area_init_node() with free_area_init_nodes(). > Either of the patches should work as long as there is not a potential problem with setting the node state before setting node_present_pages. Your suggestion may work as well but I cannot judge whether there may be side effects in relation to special case handling of node zero on m68k. Do we need to call add_active_range at the time init_bootmem_node is called? That would be a bit earlier in paging_init, and achieve much the same thing as the proposed patch or the earlier workaround. Besides, your solution would set N_HIGH_MEMORY not N_NORMAL_MEMORY if I read free_area_init_nodes() right. Does that matter? Cheers, Michael