From: Matthew Wilcox <willy@infradead.org>
To: Pavel Machek <pavel@ucw.cz>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>,
linux-mm@kvack.org, Kirill Tkhai <ktkhai@virtuozzo.com>,
Matthew Wilcox <mawilcox@microsoft.com>,
linux-kernel@vger.kernel.org,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH 3/4] mm: Add free()
Date: Tue, 3 Apr 2018 04:41:17 -0700 [thread overview]
Message-ID: <20180403114117.GA5832@bombadil.infradead.org> (raw)
In-Reply-To: <20180403085059.GB3926@amd>
On Tue, Apr 03, 2018 at 10:50:59AM +0200, Pavel Machek wrote:
> > gcc already does some nice optimisations around free(). For example, it
> > can eliminate dead stores:
>
> Are we comfortable with that optimalization for kernel?
>
> us: "Hey, let's remove those encryption keys before freeing memory."
> gcc: :-).
>
> us: "Hey, we want to erase lock magic values not to cause confusion
> later."
> gcc: "I like confusion!"
>
> Yes, these probably can be fixed by strategic "volatile" and/or
> barriers, but...
Exactly, we should mark those sites explicitly with volatile so that
they aren't dead stores.
next prev parent reply other threads:[~2018-04-03 11:41 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-22 19:58 [PATCH 0/4] Add free() function Matthew Wilcox
2018-03-22 19:58 ` [PATCH 1/4] decompression: Rename malloc and free Matthew Wilcox
2018-03-22 19:58 ` [PATCH 2/4] Rename 'free' functions Matthew Wilcox
2018-03-22 19:58 ` [PATCH 3/4] mm: Add free() Matthew Wilcox
2018-03-23 8:04 ` Rasmus Villemoes
2018-03-23 14:34 ` Matthew Wilcox
2018-04-03 8:50 ` Pavel Machek
2018-04-03 11:41 ` Matthew Wilcox [this message]
2018-03-23 13:33 ` Kirill Tkhai
2018-03-23 15:14 ` Matthew Wilcox
2018-03-23 15:49 ` Kirill Tkhai
2018-03-23 16:15 ` Matthew Wilcox
2018-03-25 23:56 ` Matthew Wilcox
2018-03-24 7:38 ` kbuild test robot
2018-03-22 19:58 ` [PATCH 4/4] rcu: Switch to using free() instead of kfree() Matthew Wilcox
2018-03-24 7:07 ` kbuild test robot
2018-03-24 8:20 ` kbuild test robot
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