Re: [patch 2/2] bootmem: Node-setup agnostic free_bootmem()

["Yinghai Lu" <yhlu.kernel@gmail.com>]

On Tue, Apr 15, 2008 at 12:51 PM, Johannes Weiner <hannes@saeurebad.de> wrote:
> Hi,
>
>
>  "Yinghai Lu" <yhlu.kernel@gmail.com> writes:
>
>  > On Tue, Apr 15, 2008 at 4:53 AM, Johannes Weiner <hannes@saeurebad.de> wrote:
>  >>
>  >> Andi Kleen <andi@firstfloor.org> writes:
>  >>
>  >>  > Andrew Morton wrote:
>  >>  >> On Sun, 13 Apr 2008 18:56:57 +0200 Andi Kleen <andi@firstfloor.org> wrote:
>  >>  >>
>  >>  >>> Johannes Weiner <hannes@saeurebad.de> writes:
>  >>  >>>
>  >>  >>>> Make free_bootmem() look up the node holding the specified address
>  >>  >>>> range which lets it work transparently on single-node and multi-node
>  >>  >>>> configurations.
>  >>  >>> Acked-by: Andi Kleen <andi@firstfloor.org>
>  >>  >>>
>  >>  >>> This is far better than the original change it replaces and which
>  >>  >>> I also objected to in review.
>  >>  >>>
>  >>  >>
>  >>  >> So...  do we think these two patches are sufficiently safe and important for
>  >>  >> 2.6.25?
>  >>  >
>  >>  > It's only strictly needed for .26 I think for some (also slightly
>  >>  > dubious) changes queued in git-x86.
>  >>
>  >>  Does anything yet rely on this new free_bootmem() behaviour?  If not,
>  >>  the safest thing would be to just revert the original patch in mainline
>  >>  and drop the second patch completely.
>  >
>  > 1. free_bootmem(ramdisk_image, ramdisk_size) in setup_arch of x86_64
>  > need that
>  > 2. another patch in x86.git need that.
>
>  Ok, to avoid confusion: we are talking about free_bootmem() iterating
>  over nodes and looking up an area WITHIN a node or free_bootmem()
>  freeing an area ACROSS nodes?
>
>  The first is what my patch does _only_.

Yes, your patch for free_bootmem only can free blocks in the same node.

but the free_bootmem(ramdisk_image,...) in setup_arch could cross
node... , and some other via reserve_early...

for example two nodes, every node have 2G, and in case use
memmap=NN$SS to execlude some memory on node1. the ramdisk could sit
cross the boundary.

YH