Re: [PATCH v11 04/21] mm: Allow page fault handlers to perform the COW

2014-10-18 Thread Matthew Wilcox
On Fri, Oct 17, 2014 at 03:35:01PM +, Mathieu Desnoyers wrote: > > > The page fault handler being very much performance sensitive, I'm > > > wondering if it would not be better to move cow_page near the end of > > > struct vm_fault, so that the "page" field can stay on the first > > > cache lin

Re: [PATCH v11 04/21] mm: Allow page fault handlers to perform the COW

2014-10-17 Thread Mathieu Desnoyers
- Original Message - > From: "Matthew Wilcox" > To: "Mathieu Desnoyers" > Cc: "Matthew Wilcox" , > linux-fsde...@vger.kernel.org, linux...@kvack.org, > linux-kernel@vger.kernel.org > Sent: Thursday, October 16, 2014 9:48:15 PM >

Re: [PATCH v11 04/21] mm: Allow page fault handlers to perform the COW

2014-10-16 Thread Matthew Wilcox
On Thu, Oct 16, 2014 at 11:12:22AM +0200, Mathieu Desnoyers wrote: > On 25-Sep-2014 04:33:21 PM, Matthew Wilcox wrote: > > Currently COW of an XIP file is done by first bringing in a read-only > > mapping, then retrying the fault and copying the page. It is much more > > efficient to tell the faul

Re: [PATCH v11 04/21] mm: Allow page fault handlers to perform the COW

2014-10-16 Thread Mathieu Desnoyers
On 25-Sep-2014 04:33:21 PM, Matthew Wilcox wrote: > Currently COW of an XIP file is done by first bringing in a read-only > mapping, then retrying the fault and copying the page. It is much more > efficient to tell the fault handler that a COW is being attempted (by > passing in the pre-allocated

[PATCH v11 04/21] mm: Allow page fault handlers to perform the COW

2014-09-25 Thread Matthew Wilcox
Currently COW of an XIP file is done by first bringing in a read-only mapping, then retrying the fault and copying the page. It is much more efficient to tell the fault handler that a COW is being attempted (by passing in the pre-allocated page in the vm_fault structure), and allow the handler to