Re: [PATCH] Add slowpath enter/exit trace events

From: Tetsuo Handa
Date: Thu Nov 23 2017 - 08:00:14 EST


On 2017/11/23 19:43, peter.enderborg@xxxxxxxx wrote:
> The warning of slow allocation has been removed, this is
> a other way to fetch that information. But you need
> to enable the trace. The exit function also returns
> information about the number of retries, how long
> it was stalled and failure reason if that happened.

However, the fast path (I mean, get_page_from_freelist() at
"/* First allocation attempt */" label) might be slow, for it is
allowed to call node_reclaim() which can take uncontrollable
duration. I think that you need to add hooks like
http://lkml.kernel.org/r/1510833448-19918-1-git-send-email-penguin-kernel@xxxxxxxxxxxxxxxxxxx does. ;-)