Re: [PATCH 3/3] mm/compaction: add tracepoint to observe behaviour of compaction defer

[Vlastimil Babka]

On 12/03/2014 08:52 AM, Joonsoo Kim wrote:
> compaction deferring logic is heavy hammer that block the way to
> the compaction. It doesn't consider overall system state, so it
> could prevent user from doing compaction falsely. In other words,
> even if system has enough range of memory to compact, compaction would be
> skipped due to compaction deferring logic. This patch add new tracepoint
> to understand work of deferring logic. This will also help to check
> compaction success and fail.
> 
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>

You only call the tracepoints from try_to_compact_pages(), but the corresponding
functions are also called from elsewhere, e.g. kswapd. Shouldn't all be
included? Otherwise one might consider the trace as showing a bug, where the
defer state suddenly changed without being captured in the trace.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/