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Re: double fault -> PAGE_KERNEL flagged memory

From: fche at redhat dot com (Frank Ch. Eigler)
To: Mathieu Desnoyers <compudj at krystal dot dyndns dot org>
Cc: michel dot dagenais at polymtl dot ca, systemtap at sources dot redhat dot com
Date: 22 Nov 2005 10:42:25 -0500
Subject: Re: double fault -> PAGE_KERNEL flagged memory
References: <CBDB88BFD06F7F408399DBCF8776B3DC05A8FB95@scsmsx403.amr.corp.intel.com> <20051122140021.GA3907@Krystal>

Mathieu Desnoyers wrote:

> [...]  For Tom : can you flag the RelayFS buffer memory PAGE_KERNEL
> instead of GFP_KERNEL ? Otherwise, it leads to page faults when
> accessing those pages when accessed for the first time (seen with
> LTTng).

FWIW, relayfs is not used by default.

> [...]  Make sure that the SystemTAP code is _always_ in contiguous
> memory non swappable to disk :

Is my impression correct that no ordinary kernel-allocated memory such
as .ko .text/.data is swappable?  Remember, this is what systemtap
creates, plus a few batches of dynamically allocated (k/vmalloc)
memory during module initialization.

- FChE

Follow-Ups:
- Re: double fault -> PAGE_KERNEL flagged memory
  - From: Mathieu Desnoyers

References:
- double fault
  - From: Stone, Joshua I
- Re: double fault -> PAGE_KERNEL flagged memory
  - From: Mathieu Desnoyers

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