netdev - Re: [PATCH net 0/2] net: revert lib/percpu_counter API for fragmentation mem accounting

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Message-Id: <20170903.110120.230269539906979454.davem@davemloft.net>
Date:   Sun, 03 Sep 2017 11:01:20 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     brouer@...hat.com
Cc:     netdev@...r.kernel.org, mkubecek@...e.cz, fw@...len.de,
        liujian56@...wei.com
Subject: Re: [PATCH net 0/2] net: revert lib/percpu_counter API for
 fragmentation mem accounting

From: Jesper Dangaard Brouer <brouer@...hat.com>
Date: Fri, 01 Sep 2017 11:26:03 +0200

> There is a bug in fragmentation codes use of the percpu_counter API,
> that can cause issues on systems with many CPUs, above 24 CPUs.
> 
> After much consideration and different attempts at solving the API
> usage.  The conclusion is to revert to the simple atomic_t API instead.
> 
> The ratio between batch size and threshold size make it a bad use-case
> for the lib/percpu_counter API.  As using the correct API calls will
> unfortunately cause systems with many CPUs to always execute an
> expensive sum across all CPUs. Plus the added complexity is not worth it.

Series applied, thanks Jesper.