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Date:   Tue, 6 Feb 2018 23:54:09 -0800
From:   Josh Triplett <josh@joshtriplett.org>
To:     "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc:     Matthew Wilcox <willy@infradead.org>,
        Kirill Tkhai <ktkhai@virtuozzo.com>, rostedt@goodmis.org,
        mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com,
        mingo@redhat.com, cl@linux.com, penberg@kernel.org,
        rientjes@google.com, iamjoonsoo.kim@lge.com,
        akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, brouer@redhat.com, rao.shoaib@oracle.com
Subject: Re: [PATCH 0/2] rcu: Transform kfree_rcu() into kvfree_rcu()
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 <20180207042334.GA16175@bombadil.infradead.org>
 <20180207050200.GH3617@linux.vnet.ibm.com>
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On Tue, Feb 06, 2018 at 09:02:00PM -0800, Paul E. McKenney wrote:
> On Tue, Feb 06, 2018 at 08:23:34PM -0800, Matthew Wilcox wrote:
> > On Tue, Feb 06, 2018 at 06:17:03PM -0800, Paul E. McKenney wrote:
> > > So it is OK to kvmalloc() something and pass it to either kfree() or
> > > kvfree(), and it had better be OK to kvmalloc() something and pass it
> > > to kvfree().
> > > 
> > > Is it OK to kmalloc() something and pass it to kvfree()?
> > 
> > Yes, it absolutely is.
> > 
> > void kvfree(const void *addr)
> > {
> >         if (is_vmalloc_addr(addr))
> >                 vfree(addr);
> >         else
> >                 kfree(addr);
> > }
> > 
> > > If so, is it really useful to have two different names here, that is,
> > > both kfree_rcu() and kvfree_rcu()?
> > 
> > I think it's handy to have all three of kvfree_rcu(), kfree_rcu() and
> > vfree_rcu() available in the API for the symmetry of calling kmalloc()
> > / kfree_rcu().
> > 
> > Personally, I would like us to rename kvfree() to just free(), and have
> > malloc(x) be an alias to kvmalloc(x, GFP_KERNEL), but I haven't won that
> > fight yet.
> 
> But why not just have the existing kfree_rcu() API cover both kmalloc()
> and kvmalloc()?  Perhaps I am not in the right forums, but I am not hearing
> anyone arguing that the RCU API has too few members.  ;-)

I don't have any problem with having just `kvfree_rcu`, but having just
`kfree_rcu` seems confusingly asymmetric.

(Also, count me in favor of having just one "free" function, too.)