linux-kernel - Re: [PATCH 1/6] lightnvm: pblk: check for failed mempool alloc.

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Message-ID: <d8295f1b-5021-e20b-ffcf-4fbbbe7c70b4@kernel.dk>
Date:   Wed, 6 Sep 2017 09:09:29 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Johannes Thumshirn <jthumshirn@...e.de>,
        Javier González <jg@...htnvm.io>
Cc:     mb@...htnvm.io, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Javier González <javier@...xlabs.com>,
        Matias Bjørling <matias@...xlabs.com>
Subject: Re: [PATCH 1/6] lightnvm: pblk: check for failed mempool alloc.

On 09/06/2017 09:08 AM, Johannes Thumshirn wrote:
> On Wed, Sep 06, 2017 at 05:01:01PM +0200, Javier González wrote:
>> Check for failed mempool allocations and act accordingly.
> 
> Are you sure it is needed? Quoting from mempool_alloc()s Documentation:
> "[...] Note that due to preallocation, this function *never* fails when called
> from process contexts. (it might fail if called from an IRQ context.) [...]"

It's not needed, mempool() will never fail if __GFP_WAIT is set in the
mask. The use case here is GFP_KERNEL, which does include __GFP_WAIT.

-- 
Jens Axboe