Re: [libvirt] [PATCH] nodeinfo: fix detection of physical memory on uclibc/musl libc
On Tue, 15 Apr 2014 10:37:40 +0100
"Daniel P. Berrange" <berrange(a)redhat.com> wrote:
On Tue, Apr 15, 2014 at 11:31:23AM +0200, Natanael Copa wrote:
> The gnulib's physmem_total will as a fallback report 64MB as total
> memory if sysconf(_SC_PHYS_PAGES) is unimplemented on linux. This makes
> it impossible to detect if physmem_total works or not, so we try first
> the linux only sysinfo(2) before falling back to gnulibs physmem_total.
>
> This makes the total memory be correctly reported on musl libc and
> uclibc.
>
> Signed-off-by: Natanael Copa <ncopa(a)alpinelinux.org>
> ---
> configure.ac | 2 +-
> src/nodeinfo.c | 22 ++++++++++++++++------
> 2 files changed, 17 insertions(+), 7 deletions(-)
I think you should instead patch the gnulib physmem_total() function
to support use of sysinfo() itself. That way all the many users of
GNULIB will work correctly on musl/uclibc, rather than just libvirt.
the intention was to fix all 3 places:
* fix libvirt not trust physmem_total
* fix gnulib to use sysinfo and fallback to sysconf
* add _SC_PHYS_PAGES support to musl libc
In any case, the gnulib's physmem_total will most likely always fall
back to 64MB instead of fail with error since it looks like thats the
way it is designed. I doubt they will accept fix for that.
That means that libvirt cannot really trust physmem_total and IMHO it
should be avoided.
The effective result is that you cannot create any vm with more than
64MB (MB not GB...) ram with virt-manager which I think is worse than
fail with error.
-nc