Re: [patch] mm: node-setup agnostic free_bootmem()

From: Yinghai Lu
Date: Sun Apr 27 2008 - 21:48:36 EST


On Sun, Apr 27, 2008 at 5:40 PM, Ingo Molnar <mingo@xxxxxxx> wrote:
>
> * Johannes Weiner <hannes@xxxxxxxxxxxx> 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@xxxxxxxxxxxx>
> 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@xxxxxxxxxxxx>
> CC: Andi Kleen <andi@xxxxxxxxxxxxxx>
> CC: Yinghai Lu <yhlu.kernel@xxxxxxxxx>
> CC: Yasunori Goto <y-goto@xxxxxxxxxxxxxx>
> CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> CC: Christoph Lameter <clameter@xxxxxxx>
> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> ---
> 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.

YH
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