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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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