 Home |
Products |
Support |
Community |
News |
xen-devel
Re: [Xen-devel] What's the purpose of VM_FOREIGN
| To: | "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx> |
|---|---|
| Subject: | Re: [Xen-devel] What's the purpose of VM_FOREIGN |
| From: | "Andrew Warfield" <andrew.warfield@xxxxxxxxxxxx> |
| Date: | Tue, 1 Aug 2006 08:30:47 -0700 |
| Cc: | "Li, Xin B" <xin.b.li@xxxxxxxxx>, xen-devel Mailing List <xen-devel@xxxxxxxxxxxxxxxxxxx> |
| Delivery-date: | Tue, 01 Aug 2006 08:31:11 -0700 |
| Domainkey-signature: | a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=jLZ+2xWMavqxHSaNPSYbVA4Dcnx2uwYINtPR3irl3JwtR+oHDZQYw62VvIo2JQI0ShQofpGDF2brMSHBLKYXHFxb0UB7YZsnAQT0Dmea+OlzGfPsH8Je64rg7mtV0zffxvX8uW9EDAuCzRoEBOkB6oDSlkYF2XlzgvRJlPp7tWg= |
| Envelope-to: | www-data@xxxxxxxxxxxxxxxxxx |
| In-reply-to: | <606d1f2ca949c6eb133c73c2e07b3e5a@xxxxxxxxxxxx> |
| List-help: | <mailto:xen-devel-request@lists.xensource.com?subject=help> |
| List-id: | Xen developer discussion <xen-devel.lists.xensource.com> |
| List-post: | <mailto:xen-devel@lists.xensource.com> |
| List-subscribe: | <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe> |
| List-unsubscribe: | <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe> |
| References: | <0EBFB99D260C5B40AC33E0F807B1AD66BD2E38@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> <606d1f2ca949c6eb133c73c2e07b3e5a@xxxxxxxxxxxx> |
| Sender: | xen-devel-bounces@xxxxxxxxxxxxxxxxxxx |
VM_FOREIGN is used to allow zero-copy of data pages for the blktap driver. When foreign block data pages are mapped to user space, the PTEs aren't backed by page structs, so get_user_pages becomes upset when called to map the block requests down onto physical page addresses. VM_FOREIGN vm_areas use the vm_private_data field to contain an array of mappings to the associate page structs, and get_user_pages uses this table to handle pages that have been foreign mapped. The code that sets up the mapping is in drivers/xen/blktap.c. a. On 8/1/06, Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> wrote: > But I never saw when the bit is set, so this code path can not be > reached? > It's used by the blktap driver. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel |
| <Prev in Thread] | Current Thread | [Next in Thread> |
|---|---|---|
| ||
| Previous by Date: | [Xen-devel] Daily Xen Builds, David F Barrera |
|---|---|
| Next by Date: | Re: [Xen-devel] I/O port access permission, Keir Fraser |
| Previous by Thread: | Re: [Xen-devel] What's the purpose of VM_FOREIGN, Keir Fraser |
| Next by Thread: | Re: [Xen-devel] [Patch] Enable "sysrq c" handler for domU coredump, Keir Fraser |
| Indexes: | [Date] [Thread] [Top] [All Lists] |
