From: Nick Piggin <npiggin@gmail.com>
To: Nick Piggin <npiggin@gmail.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Important for fs devs: rcu-walk merged upstream
Date: Wed, 12 Jan 2011 00:06:42 +1100 [thread overview]
Message-ID: <AANLkTimrqb5e9QKT7UFLXtQHap689kSoEZRmLvax5Xm-@mail.gmail.com> (raw)
In-Reply-To: <20110111010800.GE4879@mail.oracle.com>
On Tuesday, January 11, 2011, Joel Becker <jlbec@evilplan.org> wrote:
> On Sat, Jan 08, 2011 at 01:54:47PM +1100, Nick Piggin wrote:
>> The rcu-walk stuff can be more tricky for your filesystem
>> to take advantage of.
>>
>> If you supply a .d_revalidate, .permission, or .check_acl,
>> then path walking is going to be slow and unscalable for
>> you.
>
> Do you mean "as slow and unscalable as it has always been" or
> "even slower now"? A quick look suggests the former, but I wanted to be
> sure.
Yeah it should be about the same. Bit more complex code so it might be
a bit slower. A few code and branch and cache improvements so it might
be a bit faster. Refcounts on the same dentry become a bit less
scalable for using lock instead of atomic. On the other hand dropping
the ref on leaf denty doesn't require global lock.
It should not be urgent for 2.6.38.
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next prev parent reply other threads:[~2011-01-11 13:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-08 2:54 Important for fs devs: rcu-walk merged upstream Nick Piggin
2011-01-08 9:10 ` Marco Stornelli
2011-01-11 9:57 ` Nick Piggin
2011-01-11 11:08 ` Miklos Szeredi
2011-01-10 14:38 ` J. R. Okajima
2011-01-11 12:57 ` Nick Piggin
2011-01-11 1:08 ` Joel Becker
2011-01-11 13:06 ` Nick Piggin [this message]
2011-01-13 14:58 ` Miklos Szeredi
2011-01-13 16:18 ` Miklos Szeredi
2011-01-14 1:21 ` Nick Piggin
2011-01-14 8:45 ` Miklos Szeredi
2011-01-14 8:52 ` Nick Piggin
2011-01-14 9:38 ` Miklos Szeredi
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