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SubjectRe: [patch] mm: node-setup agnostic free_bootmem()
On Mon, Apr 28, 2008 at 9:54 AM, Johannes Weiner <hannes@saeurebad.de> wrote:
> Hi Yinghai,
>
>
>
> "Yinghai Lu" <yhlu.kernel@gmail.com> writes:
>
> > On Sun, Apr 27, 2008 at 5:40 PM, Ingo Molnar <mingo@elte.hu> wrote:
> >>
> >> * Johannes Weiner <hannes@saeurebad.de> wrote:
> >>
> >> > > so i very much agree that your changes are cleaner, i just wanted to
> >> > > have one that has all the fixes included.
> >> >
> >> > I had planned this to be another patch because there are more then one
> >> > boundary check I wanted to tighten. I can merge them though if you
> >> > like.
> >>
> >> no, better to have them in separate patches.
> >>
> >> > > Would you like to post a patch against current -git or should i
> >> > > extract the cleaner reserve_bootmem() from your previous patch?
> >> >
> >> > I just moved and have only sporadic internet access and free time
> >> > slots available. Would be nice if you could do it!
> >>
> >> sure, find the merged patch below, against latest -git, boot-tested on
> >> x86. Is this what you had in mind?
> >>
> >> Ingo
> >>
> >> ---------------->
> >> Subject: mm: node-setup agnostic free_bootmem()
> >> From: Johannes Weiner <hannes@saeurebad.de>
> >> Date: Wed, 16 Apr 2008 13:36:31 +0200
> >>
> >> Make free_bootmem() look up the node holding the specified address
> >> range which lets it work transparently on single-node and multi-node
> >> configurations.
> >>
> >> If the address range exceeds the node range, it well be marked free
> >> across node boundaries, too.
> >>
> >> Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
> >> CC: Andi Kleen <andi@firstfloor.org>
> >> CC: Yinghai Lu <yhlu.kernel@gmail.com>
> >> CC: Yasunori Goto <y-goto@jp.fujitsu.com>
> >> CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> >> CC: Christoph Lameter <clameter@sgi.com>
> >> CC: Andrew Morton <akpm@linux-foundation.org>
> >> Signed-off-by: Ingo Molnar <mingo@elte.hu>
> >> ---
> >> mm/bootmem.c | 27 +++++++++++++++++++++++++--
> >> 1 file changed, 25 insertions(+), 2 deletions(-)
> >>
> >> Index: linux-x86.q/mm/bootmem.c
> >> ===================================================================
> >> --- linux-x86.q.orig/mm/bootmem.c
> >> +++ linux-x86.q/mm/bootmem.c
> >> @@ -493,8 +493,31 @@ int __init reserve_bootmem(unsigned long
> >> void __init free_bootmem(unsigned long addr, unsigned long size)
> >> {
> >> bootmem_data_t *bdata;
> >> - list_for_each_entry(bdata, &bdata_list, list)
> >> - free_bootmem_core(bdata, addr, size);
> >> + unsigned long pos = addr;
> >> + unsigned long partsize = size;
> >> +
> >> + list_for_each_entry(bdata, &bdata_list, list) {
> >> + unsigned long remainder = 0;
> >> +
> >> + if (pos < bdata->node_boot_start)
> >> + continue;
> >> +
> >> + if (PFN_DOWN(pos + partsize) > bdata->node_low_pfn) {
> >> + remainder = PFN_DOWN(pos + partsize) - bdata->node_low_pfn;
> >> + partsize -= remainder;
> >> + }
> >> +
> >> + free_bootmem_core(bdata, pos, partsize);
> >> +
> >> + if (!remainder)
> >> + return;
> >> +
> >> + pos = PFN_PHYS(bdata->node_low_pfn + 1);
> >> + }
> >> + printk(KERN_ERR "free_bootmem: request: addr=%lx, size=%lx, "
> >> + "state: pos=%lx, partsize=%lx\n", addr, size,
> >> + pos, partsize);
> >> + BUG();
> >> }
> >>
> >> unsigned long __init free_all_bootmem(void)
> >>
> >
> > it will not work with cross nodes.
> >
> > for example: node 0: 0-2g, 4-6g, node1: 2-4g, 6-8g.
> > and if ramdisk sit cross 2G boundary. you will only free the range
> > before 2g.
>
> Yes, you stated that several times but this is not a technical argument:
> These setups are afaik not yet supported by the kernel at all. And you
> could not explain the node layout with the patch that implements support
> for these configurations.

I looked at Suresh's patch, and it still only has one bdata for one node.

YH


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