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Date:   Fri, 4 May 2018 20:51:54 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        linux-kernel@vger.kernel.org, tglx@linutronix.de,
        Nicholas Bellinger <nab@linux-iscsi.org>,
        Shaohua Li <shli@fb.com>,
        Kent Overstreet <kent.overstreet@gmail.com>,
        Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH] percpu_ida: Use _irqsave() instead of local_irq_save() +
 spin_lock
Message-ID: <20180505035154.GB20495@bombadil.infradead.org>
References: <20180504153218.7301-1-bigeasy@linutronix.de>
 <20180504162216.ae91654b68eddafe38df7d7f@linux-foundation.org>
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On Fri, May 04, 2018 at 04:22:16PM -0700, Andrew Morton wrote:
> I'm feeling a bit hostile toward lib/percpu_ida.c in general ;) It has
> very few users and seems rather complicated (what's with that
> schedule() in percpu_ida_alloc?).  I'm suspecting and hoping that if
> someone can figure out what the requirements were, this could all be
> zapped and reimplemented using something else which we already have.

Note that I have no code in percpu_ida ... it's quite different from
the regular IDA.  But I have noticed the stunning similarity between the
percpu_ida and the code in lib/sbitmap.c.  I have no idea which one is
better, but they're essentially doing the same thing.