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Date:   Mon, 26 Mar 2018 08:14:06 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     Kirill Tkhai <ktkhai@virtuozzo.com>
Cc:     Vladimir Davydov <vdavydov.dev@gmail.com>, viro@zeniv.linux.org.uk,
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Subject: Re: [PATCH 01/10] mm: Assign id to every memcg-aware shrinker
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On Mon, Mar 26, 2018 at 06:09:35PM +0300, Kirill Tkhai wrote:
> > AFAIK ida always allocates the smallest available id so you don't need
> > to keep track of bitmap_id_start.
> 
> I saw mnt_alloc_group_id() does the same, so this was the reason, the additional
> variable was used. Doesn't this gives a good advise to ida and makes it find
> a free id faster?

No, it doesn't help the IDA in the slightest.  I have a patch in my
tree to delete that silliness from mnt_alloc_group_id(); just haven't
submitted it yet.