Re: [PATCH 1/9] readahead: introduce PG_readahead

2007-06-11 Thread Fengguang Wu
Hi Rusty, On Tue, Jun 12, 2007 at 11:04:54AM +1000, Rusty Russell wrote: > On Thu, 2007-05-17 at 06:47 +0800, Fengguang Wu wrote: > > plain text document attachment (mm-introduce-pg_readahead.patch) > > Introduce a new page flag: PG_readahead. > > > > It acts as a look-ahead mark, which tells the

Re: [PATCH 1/9] readahead: introduce PG_readahead

2007-06-11 Thread Rusty Russell
On Thu, 2007-05-17 at 06:47 +0800, Fengguang Wu wrote: > plain text document attachment (mm-introduce-pg_readahead.patch) > Introduce a new page flag: PG_readahead. > > It acts as a look-ahead mark, which tells the page reader: > Hey, it's time to invoke the read-ahead logic. For the sake of I/O

Re: [PATCH 1/9] readahead: introduce PG_readahead

2007-05-20 Thread Christoph Lameter
On Sun, 20 May 2007, Fengguang Wu wrote: > The reuse code would look like the attached one. > It still needs more testing, and would fail if Christoph reuses > PG_reclaim in higher order pagecache in the future. Do not worry about that. All higher order pagecache patchsets remove that sharing bec

Re: [PATCH 1/9] readahead: introduce PG_readahead

2007-05-19 Thread Fengguang Wu
On Sat, May 19, 2007 at 08:25:04AM -0700, Andrew Morton wrote: > On Sat, 19 May 2007 20:30:31 +0800 Fengguang Wu <[EMAIL PROTECTED]> wrote: > > > On Fri, May 18, 2007 at 11:28:24PM -0700, Andrew Morton wrote: > > > On Thu, 17 May 2007 06:47:53 +0800 Fengguang Wu <[EMAIL PROTECTED]> wrote: > > > >

Re: [PATCH 1/9] readahead: introduce PG_readahead

2007-05-19 Thread Andrew Morton
On Sat, 19 May 2007 20:30:31 +0800 Fengguang Wu <[EMAIL PROTECTED]> wrote: > On Fri, May 18, 2007 at 11:28:24PM -0700, Andrew Morton wrote: > > On Thu, 17 May 2007 06:47:53 +0800 Fengguang Wu <[EMAIL PROTECTED]> wrote: > > > > > Introduce a new page flag: PG_readahead. > > > > Is there any way i

Re: [PATCH 1/9] readahead: introduce PG_readahead

2007-05-19 Thread Andrew Morton
On Sat, 19 May 2007 13:35:01 +0200 Andi Kleen <[EMAIL PROTECTED]> wrote: > > We have the advantage that if the kernel very occasionally gets the wrong > > result for PageReadahead(page), nothing particularly bad will happen, so we > > can do racy things. > > On 64bit there is no particular short

Re: [PATCH 1/9] readahead: introduce PG_readahead

2007-05-19 Thread Fengguang Wu
On Fri, May 18, 2007 at 11:28:24PM -0700, Andrew Morton wrote: > On Thu, 17 May 2007 06:47:53 +0800 Fengguang Wu <[EMAIL PROTECTED]> wrote: > > > Introduce a new page flag: PG_readahead. > > Is there any way in which we can avoid adding a new page flag? > > We have the advantage that if the kern

Re: [PATCH 1/9] readahead: introduce PG_readahead

2007-05-19 Thread Andi Kleen
> We have the advantage that if the kernel very occasionally gets the wrong > result for PageReadahead(page), nothing particularly bad will happen, so we > can do racy things. On 64bit there is no particular shortage of page flags. If you ever do racy things please do them 32bit only. -Andi - T

Re: [PATCH 1/9] readahead: introduce PG_readahead

2007-05-18 Thread Andrew Morton
On Thu, 17 May 2007 06:47:53 +0800 Fengguang Wu <[EMAIL PROTECTED]> wrote: > Introduce a new page flag: PG_readahead. Is there any way in which we can avoid adding a new page flag? We have the advantage that if the kernel very occasionally gets the wrong result for PageReadahead(page), nothing p