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

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Date:   Wed, 6 Sep 2017 17:12:59 +0200
From:   Johannes Thumshirn <jthumshirn@...e.de>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     Javier González <jg@...htnvm.io>,
        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 Wed, Sep 06, 2017 at 09:09:29AM -0600, Jens Axboe wrote:
> 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.

Exactly. Maybe I shouldn't have it phrased as a question though... 

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Johannes Thumshirn                                          Storage
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