From: "H. Peter Anvin" <hpa@zytor.com>
To: Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Why do we set _PAGE_DIRTY for page tables?
Date: Tue, 22 Apr 2014 16:35:29 -0700 [thread overview]
Message-ID: <5356FCC1.6060807@zytor.com> (raw)
I just noticed this:
#define _PAGE_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \
_PAGE_ACCESSED | _PAGE_DIRTY)
#define _KERNPG_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | \
_PAGE_DIRTY)
Is there a reason we set _PAGE_DIRTY for page tables? It has no
function, but doesn't do any harm either (the dirty bit is ignored for
page tables)... it just looks funny to me.
-hpa
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WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Why do we set _PAGE_DIRTY for page tables?
Date: Tue, 22 Apr 2014 16:35:29 -0700 [thread overview]
Message-ID: <5356FCC1.6060807@zytor.com> (raw)
I just noticed this:
#define _PAGE_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \
_PAGE_ACCESSED | _PAGE_DIRTY)
#define _KERNPG_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | \
_PAGE_DIRTY)
Is there a reason we set _PAGE_DIRTY for page tables? It has no
function, but doesn't do any harm either (the dirty bit is ignored for
page tables)... it just looks funny to me.
-hpa
next reply other threads:[~2014-04-22 23:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-22 23:35 H. Peter Anvin [this message]
2014-04-22 23:35 ` Why do we set _PAGE_DIRTY for page tables? H. Peter Anvin
2014-04-23 2:48 ` Linus Torvalds
2014-04-23 2:48 ` Linus Torvalds
2014-04-23 2:51 ` H. Peter Anvin
2014-04-23 2:51 ` H. Peter Anvin
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