linux-kernel - Re: [PATCH v1 00/10] vfs: getname/putname overhaul

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Message-ID: <20120908072426.2880971f@corrin.poochiereds.net>
Date:	Sat, 8 Sep 2012 07:24:26 -0400
From:	Jeff Layton <jlayton@...hat.com>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	viro@...iv.linux.org.uk, eparis@...hat.com, linux-audit@...hat.com,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 00/10] vfs: getname/putname overhaul

On Sat, 8 Sep 2012 05:08:50 +0200
Andi Kleen <andi@...stfloor.org> wrote:

> On Fri, Sep 07, 2012 at 08:54:18PM -0400, Jeff Layton wrote:
> > On Fri, 07 Sep 2012 14:26:56 -0700
> > Andi Kleen <andi@...stfloor.org> wrote:
> > 
> > > Jeff Layton <jlayton@...hat.com> writes:
> > > 
> > > > This patchset is a first pass at overhauling the getname/putname
> > > > interface to use a struct. The idea here is to add a new getname_info
> > > > struct that allow us to pass around some auxillary info along with
> > > > the string that getname() returns.
> > > 
> > > Couldn't you just use some of the free pointers in struct page?
> > > (lru etc.)
> > > 
> > > -Andi
> > > 
> > 
> > We could do that if these were page allocations. They're not, however.
> > __getname() does a PATH_MAX size allocation out of a slabcache. I get
> 
> Ok I suppose slab is faster. In this case it's better to track
> separately I agree.
> 

Ummm...stupid question...

I could see that allocating out of the slab would mean less waste when
you have >4k pages, but why would it be faster than just allocating a
page directly?

Also, by "track separately" do you mean that you think I should drop
patch 9 in this series and just do two allocations for a getname in all
cases?

-- 
Jeff Layton <jlayton@...hat.com>
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