Re: echo dev > /sys/fs/bcache/register gives page allocation failure: order:4, mode:0x2040d0

On Mon, Feb 15, 2016 at 01:02:55PM +0100, Johannes Thumshirn wrote:

quoted

So I did
make-bcache -B /dev/md5
echo /dev/md5 > /sys/fs/bcache/register

and it fails:
bash: page allocation failure: order:4, mode:0x2040d0

Is this system under some kind of memory preassure? Did this happen right
after boot or when the system was already running for quite some time?

 
Uptime 17 days, it's a server that does a lot of I/O, but free shows I have
6GB available for buffer cache out of 8, so that shouldn't be too bad. Seems
like I'm hitting an issue with memory fragmentation or a specific kind of
memory not being available?
(but I don't have any other kernel processes complaining about memory
allocation failure, at least not consistently like here)

On Mon, Feb 15, 2016 at 03:11:04AM -0900, Kent Overstreet wrote:

quoted

and it fails:
bash: page allocation failure: order:4, mode:0x2040d0

You want CONFIG_COMPACTION=y

Good suggestion, but I already have it:
gargamel:~# grep CONFIG_COMPACTION /boot/config-4.3.3-amd64-i915-volpreempt-20150421
CONFIG_COMPACTION=y

Thanks for the replies,
Marc
-- 
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