Re: 4.14-rc2 on thinkpad x220: out of memory when inserting mmc card

From: Michal Hocko
Date: Mon Oct 02 2017 - 10:44:24 EST

On Sun 01-10-17 12:26:47, Pavel Machek wrote:
> Hi!
> > I inserted u-SD card, only to realize that it is not detected as it
> > should be. And dmesg indeed reveals:
> Tetsuo asked me to report this to linux-mm.
> But 2^4 is 16 pages, IIRC that can't be expected to work reliably, and
> thus this sounds like MMC bug, not mm bug.

Well, I cannot comment on why MMC needs such a large allocation and
whether it can safely fall back to vmalloc but __GFP_RETRY_MAYFAIL
might help to try harder and require compaction to do more work.
Relying on that for correctness is, of course, a different story and
a very unreliable under memory pressure or long term fragmented memory.
Michal Hocko