From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yasunori Goto Date: Wed, 13 Jul 2005 05:09:19 +0000 Subject: Re: [PATCH] gurantee DMA area for alloc_bootmem_low() Message-Id: <20050713110109.F796.Y-GOTO@jp.fujitsu.com> List-Id: References: <20050712152715.44CD.Y-GOTO@jp.fujitsu.com> <9320000.1121179193@[10.10.2.4]> In-Reply-To: <9320000.1121179193@[10.10.2.4]> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Martin J. Bligh" Cc: linux-mm , "Luck, Tony" , linux-ia64@vger.kernel.org > > To avoid this panic, following patch skips no DMA'ble node when > > lower address is required. > > I tested this patch on my Tiger 4 and our new server. > > Seems reasonable ... but do you not want to check that the returned > ptr is actually less than MAX_DMA_ADDRESS as well? Well... If there isn't enough DMA area in a node by too much lower memory request or by something strange memory map in the node, its case might occur. I don't know it will really happen. But, the after check might be better than nothing. To tell the truth, I did the after check at first "instead of" previous check like this patch. In its patch, if its DMA check failed, allocated area are should be freed by free_bootmem_core(). But hung up occurred by it, and I changed my patch to previous check instead of deep investigation of its hung up. Ok. I'll investigate more. Thanks. -- Yasunori Goto