From: Eli Cohen <mlxk@mellanox.co.il>
To: linux-kernel@vger.kernel.org
Subject: get_user_pages question
Date: Sat, 01 May 2004 14:12:24 +0300 [thread overview]
Message-ID: <40938618.1090100@mellanox.co.il> (raw)
Hi,
I have been tryin to use get_user_pages() on malloced memory and get the
list of pages but it does not work as
I expected:
1. malloc a buffer in user space
2. issue ioctl, invoke get_user_pages() and save the page descriptors I
obtained.
3. at a later time, issue another ioctl, invoke get_user_pages() again
and save another copy of the page descriptors.
4. Compare the two lists of page descriptors. They're not all the same.
Apparently some pages were discarded and the subsequent page fault
brought a new page. I expected the original page to be in the swap cache
and get the old page again. I repeated the experiment but before the
first ioctl I wrote something to all the pages but got the same results.
I used 2.4.21-4 (RH AS 3.0).
Can anyone clarify?
thanks
Eli
next reply other threads:[~2004-05-01 11:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-01 11:12 Eli Cohen [this message]
2004-05-01 11:32 ` get_user_pages question Arjan van de Ven
2004-05-01 11:41 ` Eli Cohen
2009-11-09 6:50 Mark Veltzer
2009-11-09 9:31 ` Andi Kleen
2009-11-09 10:32 ` Hugh Dickins
2009-11-09 22:13 ` Mark Veltzer
2009-11-10 16:33 ` Hugh Dickins
2009-11-28 18:50 ` Andrea Arcangeli
2009-11-28 22:22 ` Mark Veltzer
2009-11-30 12:01 ` Nick Piggin
2009-11-30 16:12 ` Andrea Arcangeli
2009-11-30 11:54 ` Nick Piggin
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