On Thu, 2008-01-24 at 12:36 +1100, Nick Piggin wrote:
> On Thursday 24 January 2008 04:05, Linus Torvalds wrote:
> > On Wed, 23 Jan 2008, Anton Salikhmetov wrote:
> > > +
> > > + if (pte_dirty(*pte) && pte_write(*pte)) {
> >
> > Not correct.
> >
> > You still need to check "pte_present()"
On Thursday 24 January 2008 04:05, Linus Torvalds wrote:
> On Wed, 23 Jan 2008, Anton Salikhmetov wrote:
> > +
> > + if (pte_dirty(*pte) && pte_write(*pte)) {
>
> Not correct.
>
> You still need to check "pte_present()" before you can test any other
> bits. For a non-present pte, none of
On Wed, 23 Jan 2008, Linus Torvalds wrote:
>
> So we certainly *could* make ramfs/tmpfs claim they do dirty accounting,
> but just having a no-op writeback. Without that, they'd need something
> really special in the file time updates.
What we might reasonably choose to end up doing there (in 2
On Thu, 24 Jan 2008, Miklos Szeredi wrote:
>
> But I still think this approach should work. Untested, might eat your
> children, so please don't apply to any kernel.
Yes, something like that should work.
The important part is to not do the "TestClearPageDirty()" separately, the
rest of it ca
> > How about doing it in a separate pass, similarly to
> > wait_on_page_writeback()? Just instead of waiting, clean the page
> > tables for writeback pages.
>
> That sounds like a good idea, but it doesn't work.
>
> The thing is, we need to hold the page-table lock over the whole sequence
> of
On Wed, 23 Jan 2008, Hugh Dickins wrote:
>
> Something I dislike about it, though, is that it leaves the RAM-backed
> filesystems (ramfs, tmpfs, whatever) behaving visibly differently from
> the others.
I hear you.
But I'm not seeing many alternatives, unless we start taking write faults
on
On Wed, 23 Jan 2008, Linus Torvalds wrote:
> On Wed, 23 Jan 2008, Miklos Szeredi wrote:
>
> > Sure, I would have though all of this stuff is 2.6.25, but it's your
> > kernel... :)
>
> Well, the plain added "file_update_time()" call addition looked like a
> trivial fix, and if there are actually
On Wed, 23 Jan 2008, Miklos Szeredi wrote:
>
> Yeah, nasty.
>
> How about doing it in a separate pass, similarly to
> wait_on_page_writeback()? Just instead of waiting, clean the page
> tables for writeback pages.
That sounds like a good idea, but it doesn't work.
The thing is, we need to ho
> So it's not horribly hard, but it's kind of a separate issue right now.
> And while the *generic* page-writeback is easy enough to fix, I worry
> about low-level filesystems that have their own "writepages()"
> implementation. They could easily get that wrong.
Yeah, nasty.
How about doing it
On Wed, 23 Jan 2008, Miklos Szeredi wrote:
>
> > [ Side note: it is quite possible that we should not do the
> > SYNC_FILE_RANGE_WAIT_BEFORE on MS_ASYNC, and just skip over pages that
> > are busily under writeback already.
>
> MS_ASYNC is not supposed to wait, so SYNC_FILE_RANGE_WAIT_BEFO
> >
> > It would need some addition piece to not call msync_interval() for
> > MS_SYNC, and remove the balance_dirty_pages_ratelimited_nr() stuff.
> >
> > But yeah, this pte walker is much better.
>
> Actually, I think this patch is much better.
>
> Anyway, it's better because:
> - it actual
On Wed, 23 Jan 2008, Peter Zijlstra wrote:
>
> It would need some addition piece to not call msync_interval() for
> MS_SYNC, and remove the balance_dirty_pages_ratelimited_nr() stuff.
>
> But yeah, this pte walker is much better.
Actually, I think this patch is much better.
Anyway, it's bet
On Wed, 2008-01-23 at 09:05 -0800, Linus Torvalds wrote:
> So here's even a patch to get you started. Do this:
>
> git revert 204ec841fbea3e5138168edbc3a76d46747cc987
>
> and then use this appended patch on top of that as a starting point for
> something that compiles and *possibly* work
2008/1/23, Linus Torvalds <[EMAIL PROTECTED]>:
>
>
> On Wed, 23 Jan 2008, Anton Salikhmetov wrote:
> > +
> > + if (pte_dirty(*pte) && pte_write(*pte)) {
>
> Not correct.
>
> You still need to check "pte_present()" before you can test any other
> bits. For a non-present pte, none of the
On Wed, 23 Jan 2008, Anton Salikhmetov wrote:
> +
> + if (pte_dirty(*pte) && pte_write(*pte)) {
Not correct.
You still need to check "pte_present()" before you can test any other
bits. For a non-present pte, none of the other bits are defined, and for
all we know there might be ar
2008/1/23, Miklos Szeredi <[EMAIL PROTECTED]>:
> > > Also, it still doesn't make sense to me why we'd not need to walk the
> > > rmap, it is all the same file after all.
> >
> > It's the same file, but not the same memory map. It basically depends
> > on how you define msync:
> >
> > a) sync _fil
2008/1/23, Peter Zijlstra <[EMAIL PROTECTED]>:
>
> On Wed, 2008-01-23 at 02:21 +0300, Anton Salikhmetov wrote:
>
> > +static void vma_wrprotect_pmd_range(struct vm_area_struct *vma, pmd_t *pmd,
> > + unsigned long start, unsigned long end)
> > +{
> > + while (start < end) {
> > +
> > Also, it still doesn't make sense to me why we'd not need to walk the
> > rmap, it is all the same file after all.
>
> It's the same file, but not the same memory map. It basically depends
> on how you define msync:
>
> a) sync _file_ on region defined by this mmap/start/end-address
> b) s
> Force file times update at the next write reference after
> calling the msync() system call with the MS_ASYNC flag.
>
> Signed-off-by: Anton Salikhmetov <[EMAIL PROTECTED]>
> ---
> mm/msync.c | 92 +--
> 1 files changed, 82 insertions(+)
> On Wed, 2008-01-23 at 09:47 +0100, Peter Zijlstra wrote:
> > On Wed, 2008-01-23 at 02:21 +0300, Anton Salikhmetov wrote:
>
> > > +static void vma_wrprotect(struct vm_area_struct *vma)
> > > +{
> > > + unsigned long addr = vma->vm_start;
> > > + pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
> > > +
On Wed, 2008-01-23 at 09:47 +0100, Peter Zijlstra wrote:
> On Wed, 2008-01-23 at 02:21 +0300, Anton Salikhmetov wrote:
> > +static void vma_wrprotect(struct vm_area_struct *vma)
> > +{
> > + unsigned long addr = vma->vm_start;
> > + pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
> > +
> > + whi
On Wed, 2008-01-23 at 02:21 +0300, Anton Salikhmetov wrote:
> +static void vma_wrprotect_pmd_range(struct vm_area_struct *vma, pmd_t *pmd,
> + unsigned long start, unsigned long end)
> +{
> + while (start < end) {
> + spinlock_t *ptl;
> + pte_t *pte = pte_o
Force file times update at the next write reference after
calling the msync() system call with the MS_ASYNC flag.
Signed-off-by: Anton Salikhmetov <[EMAIL PROTECTED]>
---
mm/msync.c | 92 +--
1 files changed, 82 insertions(+), 10 deletions
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