Michal Hocko wrote: > 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.
Linus Walleij answered that kvmalloc() is against the design of the bounce buffer at http://lkml.kernel.org/r/cacrpkdyirc+rh_kalgvqkzmjq2dgbw4oi9mjkmrzwn+1o+9...@mail.gmail.com .
