Re: [PATCH v2 02/40] tracing: Add support to detect and avoid duplicates

From: Steven Rostedt
Date: Wed Sep 06 2017 - 14:32:54 EST


On Tue, 5 Sep 2017 16:57:14 -0500
Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx> wrote:

> From: Vedang Patel <vedang.patel@xxxxxxxxx>
>
> A duplicate in the tracing_map hash table is when 2 different entries
> have the same key and, as a result, the key_hash. This is possible due
> to a race condition in the algorithm. This race condition is inherent to
> the algorithm and not a bug. This was fine because, until now, we were
> only interested in the sum of all the values related to a particular
> key (the duplicates are dealt with in tracing_map_sort_entries()). But,
> with the inclusion of variables[1], we are interested in individual
> values. So, it will not be clear what value to choose when
> there are duplicates. So, the duplicates need to be removed.
>


> [1] - https://lkml.org/lkml/2017/6/26/751

FYI, something like this should have:

Link: http://lkml.kernel.org/r/cover.1498510759.git.tom.zanussi@xxxxxxxxxxxxxxx

And avoid any non kernel.org archiving system.

-- Steve

>
> Signed-off-by: Vedang Patel <vedang.patel@xxxxxxxxx>
> ---
>