[LTP] [PATCH v2] move_pages12: Make sure hugepages are available

[Cyril Hrubis]

Hi!
> "hugepages-2048kB" in path above will work only on systems with 2M huge pages.

Do you have a ppc64 numa machine with more than two nodes at hand? Since
that is the only one where the current code may fail. Both x86_64 and
aarch64 seems to have 2MB huge pages.

I would just go with this patch now, and possibly fix more complicated
corner cases after the release, since this patch is the last problem
that holds the release from my side.

Anything else that should be taken care of before the release?

> > +
> > +	if (!access(path_hugepages_node1, F_OK)) {
> > +		SAFE_FILE_SCANF(path_hugepages_node1,
> > +				"%ld", &orig_hugepages_node1);
> > +		tst_res(TINFO, "Increasing hugepages pool on node %u to %ld",
> > +			node1, orig_hugepages_node1 + 4);
> > +		SAFE_FILE_PRINTF(path_hugepages_node1,
> > +				 "%ld", orig_hugepages_node1 + 4);
> 
> There doesn't seem to be any error if you ask for more:
> 
> # echo 20000 > /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
> # cat /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
> 11650
> 
> So, maybe we can just read it back and if it doesn't match what we requested,
> we can TCONF.

Or we may try to allocate 4 huge pages on both nodes even in a case that
we set the per-node limits that should catch the problem as well. Is
that OK with you?

-- 
Cyril Hrubis
chrubis@suse.cz