Re: [RFC] scripts: Include postprocessing script for memory allocation tracing

From: Janani Ravichandran
Date: Fri Sep 23 2016 - 01:51:32 EST

> On Sep 19, 2016, at 5:42 AM, Michal Hocko <mhocko@xxxxxxxxxx> wrote:
> On Tue 13-09-16 14:04:49, Janani Ravichandran wrote:
>>> On Sep 12, 2016, at 8:16 AM, Michal Hocko <mhocko@xxxxxxxxxx> wrote:
>> Iâm using the function graph tracer to see how long __alloc_pages_nodemask()
>> took.
> How can you map the function graph tracer to a specif context? Let's say
> I would like to know why a particular allocation took so long. Would
> that be possible?

Maybe not. If the latencies are due to direct reclaim or memory compaction, you
get some information from the tracepoints (like mm_vmscan_direct_reclaim_begin,
mm_compaction_begin, etc). But otherwise, you donât get any context information.
Function graph only gives the time spent in alloc_pages_nodemask() in that case.

> --
> Michal Hocko
> SUSE Labs