Hi,
> I guess the downside to this is if a reader is reading a large file, or
> several files, sequentially with a small read size (smaller than
> PAGE_SIZE), the pages will be marked active after just one read pass.
> My gut says the benefits of this patch outweigh the cost. I would
> expect re
[EMAIL PROTECTED] wrote:
On the other hand, Andreas suggested only marking it once every 32 calls,
but that required a helper variable. Statistically, jiffies%32 should
end up about the same as a helper variable %32.
This of course, if just calling mark_page_accessed() is actually expensive
en
On Thu, 15 Mar 2007 14:35:17 EDT, Rik van Riel said:
> [EMAIL PROTECTED] wrote:
> > On Wed, 14 Mar 2007 22:33:17 BST, Andreas Mohr said:
> >
> >> it'd seem we need some kind of state management here to figure out good
> >> intervals of when to call mark_page_accessed() *again* for this page. E.g.
On Thu, Mar 15, 2007 at 06:15:45PM -0500, Dave Kleikamp wrote:
> On Thu, 2007-03-15 at 23:59 +0100, Andrea Arcangeli wrote:
> > On Thu, Mar 15, 2007 at 05:44:01PM +, Hugh Dickins wrote:
> > > who removed the !offset condition, he should be consulted on its
> > > reintroduction.
> >
> > the !of
On Thu, 2007-03-15 at 23:59 +0100, Andrea Arcangeli wrote:
> On Thu, Mar 15, 2007 at 05:44:01PM +, Hugh Dickins wrote:
> > who removed the !offset condition, he should be consulted on its
> > reintroduction.
>
> the !offset check looks a pretty broken heuristic indeed, it would
> break random
On Thu, Mar 15, 2007 at 03:06:01PM -0700, Andrew Morton wrote:
> On Thu, 15 Mar 2007 22:49:23 +0100
> Andrea Arcangeli <[EMAIL PROTECTED]> wrote:
>
> > On Thu, Mar 15, 2007 at 11:07:35AM -0800, Andrew Morton wrote:
> > > > On Thu, 15 Mar 2007 01:22:45 -0400 (EDT) Ashif Harji <[EMAIL
> > > > PROTE
On Thu, Mar 15, 2007 at 05:44:01PM +, Hugh Dickins wrote:
> who removed the !offset condition, he should be consulted on its
> reintroduction.
the !offset check looks a pretty broken heuristic indeed, it would
break random I/O. The real fix is to add a ra.prev_offset along with
ra.prev_page, a
On Thu, 15 Mar 2007 22:49:23 +0100
Andrea Arcangeli <[EMAIL PROTECTED]> wrote:
> On Thu, Mar 15, 2007 at 11:07:35AM -0800, Andrew Morton wrote:
> > > On Thu, 15 Mar 2007 01:22:45 -0400 (EDT) Ashif Harji <[EMAIL PROTECTED]>
> > > wrote:
> > > I still think the simple fix of removing the
> > > con
On Thu, Mar 15, 2007 at 11:07:35AM -0800, Andrew Morton wrote:
> > On Thu, 15 Mar 2007 01:22:45 -0400 (EDT) Ashif Harji <[EMAIL PROTECTED]>
> > wrote:
> > I still think the simple fix of removing the
> > condition is the best approach, but I'm certainly open to alternatives.
>
> Yes, the problem
Hi,
On Thu, Mar 15, 2007 at 09:07:39PM +0100, Nick Piggin wrote:
> Well in general we like to help applications that help themselves. It
> is actually a good heuristic, surprisingly. If an application randomly
> accesses the same page (and there is no write activity going on), then
> it would be b
On Thu, Mar 15, 2007 at 03:55:08PM -0400, Ashif Harji wrote:
>
> It sounds like people are happy with the fix suggested by Nick. That fix
> is okay with me as it fixes the problem I am having.
>
> I suspect, however, that by not directly detecting the problematic access
> pattern, where the fi
On Thu, Mar 15, 2007 at 05:44:01PM +, Hugh Dickins wrote:
> On Thu, 15 Mar 2007, Nick Piggin wrote:
> > On Thu, Mar 15, 2007 at 11:56:59AM -0400, Chuck Ebbert wrote:
> > > Ashif Harji wrote:
> > > >
> > > > This patch unconditionally calls mark_page_accessed to prevent pages,
> > > > especiall
On Thu, 15 Mar 2007, Nick Piggin wrote:
On Thu, Mar 15, 2007 at 11:56:59AM -0400, Chuck Ebbert wrote:
Ashif Harji wrote:
This patch unconditionally calls mark_page_accessed to prevent pages,
especially for small files, from being evicted from the page cache
despite frequent access.
Signed-
> On Thu, 15 Mar 2007 01:22:45 -0400 (EDT) Ashif Harji <[EMAIL PROTECTED]>
> wrote:
> I still think the simple fix of removing the
> condition is the best approach, but I'm certainly open to alternatives.
Yes, the problem of falsely activating pages when the file is read in small
hunks is worse
[EMAIL PROTECTED] wrote:
On Wed, 14 Mar 2007 22:33:17 BST, Andreas Mohr said:
it'd seem we need some kind of state management here to figure out good
intervals of when to call mark_page_accessed() *again* for this page. E.g.
despite non-changing access patterns you could still call mark_page_ac
On Thu, 15 Mar 2007, Nick Piggin wrote:
> On Thu, Mar 15, 2007 at 11:56:59AM -0400, Chuck Ebbert wrote:
> > Ashif Harji wrote:
> > >
> > > This patch unconditionally calls mark_page_accessed to prevent pages,
> > > especially for small files, from being evicted from the page cache
> > > despite fr
On Wed, 14 Mar 2007 22:33:17 BST, Andreas Mohr said:
> it'd seem we need some kind of state management here to figure out good
> intervals of when to call mark_page_accessed() *again* for this page. E.g.
> despite non-changing access patterns you could still call mark_page_accessed(
)
> every 32 c
Nick Piggin wrote:
A change to make database style random read() workloads perform better, by
calling mark_page_accessed for some non-page-aligned reads broke the case of
< PAGE_CACHE_SIZE files, which will not get their prev_index moved past the
first page.
Combine both heuristics for marking
On Thu, Mar 15, 2007 at 11:56:59AM -0400, Chuck Ebbert wrote:
> Ashif Harji wrote:
> >
> > This patch unconditionally calls mark_page_accessed to prevent pages,
> > especially for small files, from being evicted from the page cache
> > despite frequent access.
> >
> > Signed-off-by: Ashif Harji <
Ashif Harji wrote:
>
> This patch unconditionally calls mark_page_accessed to prevent pages,
> especially for small files, from being evicted from the page cache
> despite frequent access.
>
> Signed-off-by: Ashif Harji <[EMAIL PROTECTED]>
>
I like mine better -- it leaves the comment:
From:
Nick Piggin wrote:
On Thu, Mar 15, 2007 at 11:39:14AM +0100, Peter Zijlstra wrote:
On Wed, 2007-03-14 at 15:58 -0400, Ashif Harji wrote:
This patch unconditionally calls mark_page_accessed to prevent pages,
especially for small files, from being evicted from the page cache despite
frequent acc
Andreas Mohr wrote:
I've been thinking hard how to avoid the mark_page_accessed() starvation in
case of a fixed, (almost) non-changing access state, but this seems hard since
it'd seem we need some kind of state management here to figure out good
intervals of when to call mark_page_accessed() *a
On Thu, Mar 15, 2007 at 07:46:56AM -0500, Dave Kleikamp wrote:
> On Thu, 2007-03-15 at 01:22 -0400, Ashif Harji wrote:
>
> > I would tend to agree with David that: "Any application doing many
> > tiny-sized reads isn't exactly asking for great performance." As well,
> > applications concerned
On Thu, 2007-03-15 at 01:22 -0400, Ashif Harji wrote:
> I would tend to agree with David that: "Any application doing many
> tiny-sized reads isn't exactly asking for great performance." As well,
> applications concerned with performance and caching problems can read in a
> file in PAGE_SIZE
On Thu, Mar 15, 2007 at 11:39:14AM +0100, Peter Zijlstra wrote:
> On Wed, 2007-03-14 at 15:58 -0400, Ashif Harji wrote:
> > This patch unconditionally calls mark_page_accessed to prevent pages,
> > especially for small files, from being evicted from the page cache despite
> > frequent access.
>
On Wed, 2007-03-14 at 15:58 -0400, Ashif Harji wrote:
> This patch unconditionally calls mark_page_accessed to prevent pages,
> especially for small files, from being evicted from the page cache despite
> frequent access.
Since we're hackling over the use-once stuff again...
/me brings up: http
On Wed, 14 Mar 2007, Xiaoning Ding wrote:
Dave Kleikamp wrote:
On Wed, 2007-03-14 at 22:33 +0100, Andreas Mohr wrote:
Hi,
On Wed, Mar 14, 2007 at 03:55:41PM -0500, Dave Kleikamp wrote:
On Wed, 2007-03-14 at 15:58 -0400, Ashif Harji wrote:
This patch unconditionally calls mark_page_accessed
Dave Kleikamp wrote:
On Wed, 2007-03-14 at 22:33 +0100, Andreas Mohr wrote:
Hi,
On Wed, Mar 14, 2007 at 03:55:41PM -0500, Dave Kleikamp wrote:
On Wed, 2007-03-14 at 15:58 -0400, Ashif Harji wrote:
This patch unconditionally calls mark_page_accessed to prevent pages,
especially for small files
On Wed, 2007-03-14 at 22:33 +0100, Andreas Mohr wrote:
> Hi,
>
> On Wed, Mar 14, 2007 at 03:55:41PM -0500, Dave Kleikamp wrote:
> > On Wed, 2007-03-14 at 15:58 -0400, Ashif Harji wrote:
> > > This patch unconditionally calls mark_page_accessed to prevent pages,
> > > especially for small files, f
Hi,
On Wed, Mar 14, 2007 at 03:55:41PM -0500, Dave Kleikamp wrote:
> On Wed, 2007-03-14 at 15:58 -0400, Ashif Harji wrote:
> > This patch unconditionally calls mark_page_accessed to prevent pages,
> > especially for small files, from being evicted from the page cache despite
> > frequent access.
On Wed, 2007-03-14 at 15:58 -0400, Ashif Harji wrote:
> This patch unconditionally calls mark_page_accessed to prevent pages,
> especially for small files, from being evicted from the page cache despite
> frequent access.
I guess the downside to this is if a reader is reading a large file, or
se
This patch unconditionally calls mark_page_accessed to prevent pages,
especially for small files, from being evicted from the page cache despite
frequent access.
Signed-off-by: Ashif Harji <[EMAIL PROTECTED]>
---
If the same page of a file is repeatedly accessed (without accessing other
pa
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