linux-kernel - RE: Can Linux live without DMA zone?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <FFECF24D2A7F6D418B9511AF6F358602F2D4E1@shacnexch2.atitech.com>
Date:	Thu, 2 Nov 2006 11:43:38 +0800
From:	"Conke Hu" <conke.hu@....com>
To:	"Jun Sun" <jsun@...sun.net>, <linux-kernel@...r.kernel.org>
Subject: RE: Can Linux live without DMA zone?

It seems a good idea.
Is dma zone is still necessay on most modern computers?

Best regards,
Conke @ AMD, Inc.

-----Original Message-----
From: linux-kernel-owner@...r.kernel.org [mailto:linux-kernel-owner@...r.kernel.org] On Behalf Of Jun Sun
Sent: 2006年11月2日 10:16
To: linux-kernel@...r.kernel.org
Subject: Can Linux live without DMA zone?

I am trying to reserve a block of memory (>16MB) starting from 0 and hide it 
from kernel.  A consequence is that DMA zone now has size 0.  That causes
many drivers to grief (OOMs).

I see two ways out:

1. Modify individual drivers and convince them not to alloc with GFP_DMA.
   I have been trying to do this but do not seem to see an end of it.  :)

2. Simply lie and increase MAX_DMA_ADDRESS to really big (like 1GB) so that
   the whole memory region belongs to DMA zone.

#2 sounds pretty hackish.  I am sure something bad will happen
sooner or later (like what?). But so far it appears to be working fine.

The fundamental question is: Has anybody tried to run Linux without 0 sized
DMA zone before?  Am I doing something that nobody has done before (which is
something really hard to believe these days with Linux :P)?

Cheers.

Jun
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/