On Mon, 7 May 2001, Marcelo Tosatti wrote:
So what about moving the check for a dead swap cache page from
swap_writepage() to page_launder() (+ PageSwapCache() check) just before
the if (!launder_loop) ?
Yes, its ugly special casing. Any other suggestion ?
My most favourite approach
On Mon, 7 May 2001, David S. Miller wrote:
Here, let's talk code a little bit so there are no misunderstandings,
I really want to put this to rest:
Calculate dead_swap_page outside of lock.
NO. That's not what you're doing at all. You're calculating something
completely different that
On Sun, 6 May 2001, David S. Miller wrote:
It is the most straightforward way to make a '1' or '0'
integer from the NULL state of a pointer.
But is it really specified in the C standards to be exctly zero or one,
and not zero and non-zero?
IMHO, the ?: construct is way more readable and
Tobias Ringstrom writes:
But is it really specified in the C standards to be exctly zero or one,
and not zero and non-zero?
I'm pretty sure it does.
IMHO, the ?: construct is way more readable and reliable.
Well identical code has been there for several months just a few lines
away.
Tobias Ringstrom wrote:
On Sun, 6 May 2001, David S. Miller wrote:
It is the most straightforward way to make a '1' or '0'
integer from the NULL state of a pointer.
But is it really specified in the C standards to be exctly zero or one,
and not zero and non-zero?
!0 is 1. !(anything
It is the most straightforward way to make a '1' or '0'
integer from the NULL state of a pointer.
But is it really specified in the C standards to be exctly zero or one,
and not zero and non-zero?
Yes. (Fortunately since when this argument occurred Linus said he would eat
his underpants
Followup to: [EMAIL PROTECTED]
By author:Tobias Ringstrom [EMAIL PROTECTED]
In newsgroup: linux.dev.kernel
On Sun, 6 May 2001, David S. Miller wrote:
It is the most straightforward way to make a '1' or '0'
integer from the NULL state of a pointer.
But is it really specified in the C
In article [EMAIL PROTECTED],
BERECZ Szabolcs [EMAIL PROTECTED] wrote:
there is a bug in page_launder introduced with kernel 2.4.3-ac12.
Yes.
The whole dead_swap_page optimization in the -ac tree is apparentrly
completely bogus. It caches a value that is not valid: you cannot
reliably look
On 05.07 Helge Hafting wrote:
Tobias Ringstrom wrote:
On Sun, 6 May 2001, David S. Miller wrote:
It is the most straightforward way to make a '1' or '0'
integer from the NULL state of a pointer.
But is it really specified in the C standards to be exctly zero or one,
and not
Linus Torvalds writes:
The whole dead_swap_page optimization in the -ac tree is apparentrly
completely bogus. It caches a value that is not valid: you cannot
reliably look at whether the page has buffers etc without holding the
page locked.
It caches a value controlling heuristics,
On 7 May 2001, Linus Torvalds wrote:
But it is important to re-calculate the deadness after getting the
lock. Before, it was just an informed guess. After the lock, it is
knowledge. And you can use informed guesses for heuristics, but you
must _not_ use them for any serious decisions.
And
On Mon, 7 May 2001, Marcelo Tosatti wrote:
On 7 May 2001, Linus Torvalds wrote:
But it is important to re-calculate the deadness after getting the
lock. Before, it was just an informed guess. After the lock, it is
knowledge. And you can use informed guesses for heuristics, but you
On Mon, 7 May 2001, Linus Torvalds wrote:
On Mon, 7 May 2001, Marcelo Tosatti wrote:
On 7 May 2001, Linus Torvalds wrote:
But it is important to re-calculate the deadness after getting the
lock. Before, it was just an informed guess. After the lock, it is
knowledge. And you
On Mon, 7 May 2001, Marcelo Tosatti wrote:
So the dead_swap_page logic is _not_ buggy and you are full of shit when
telling Alan to revert the change. (sorry, I could not avoid this one)
Well, the problem is that the patch _is_ buggy.
swap_writepage() does it right. And dead_swap_page
On Mon, 7 May 2001, Linus Torvalds wrote:
On Mon, 7 May 2001, Marcelo Tosatti wrote:
So the dead_swap_page logic is _not_ buggy and you are full of shit when
telling Alan to revert the change. (sorry, I could not avoid this one)
Well, the problem is that the patch _is_ buggy.
On Mon, 7 May 2001, Marcelo Tosatti wrote:
So lets fix it and make it look for the swap counts.
Ehh.
Which you MUST NOT do without holding the page lock.
Hint: it needs page-index, and without holding the page lock you don't
know what it could be. An out-of-bounds page index could do
On Mon, 7 May 2001, David S. Miller wrote:
Marcelo Tosatti writes:
I just thought about this case:
We find a dead swap cache page, so dead_swap_page goes to 1.
We call swap_writepage(), but in the meantime the swapin readahead code
got a reference on the swap map for
On Mon, 7 May 2001, David S. Miller wrote:
Marcelo Tosatti writes:
I just thought about this case:
We find a dead swap cache page, so dead_swap_page goes to 1.
We call swap_writepage(), but in the meantime the swapin readahead code
got a reference on the swap map for
On Mon, 7 May 2001, David S. Miller wrote:
Marcelo Tosatti writes:
I was wrong. The patch is indeed buggy because of the __GFP_IO thing.
What about the __GFP_IO thing?
Specifically, what protects the __GFP_IO thing from happening without
my patch?
This:
/*
On Sun, May 06, 2001 at 09:55:26PM -0700, David S. Miller wrote:
>
> Jonathan Morton writes:
> > >- page_count(page) == (1 + !!page->buffers));
> > Two inversions in a row?
> It is the most straightforward way to make a '1' or '0'
> integer from the NULL state of a pointer.
Jonathan Morton writes:
> >-page_count(page) == (1 + !!page->buffers));
>
> Two inversions in a row?
It is the most straightforward way to make a '1' or '0'
integer from the NULL state of a pointer.
Later,
David S. Miller
[EMAIL PROTECTED]
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To unsubscribe from this
At 12:07 AM +0200 2001-05-07, BERECZ Szabolcs wrote:
>On Sun, 6 May 2001, Jonathan Morton wrote:
>
> > >- page_count(page) == (1 + !!page->buffers));
>>
>> Two inversions in a row? I'd like to see that made more explicit,
>> otherwise it looks like a bug to me. Of course, if
Hi!
On Sun, 6 May 2001, Jonathan Morton wrote:
> >- page_count(page) == (1 + !!page->buffers));
>
> Two inversions in a row? I'd like to see that made more explicit,
> otherwise it looks like a bug to me. Of course, if it IS a bug...
it's not a bug.
if page->buffers is
>- page_count(page) == (1 + !!page->buffers));
Two inversions in a row? I'd like to see that made more explicit,
otherwise it looks like a bug to me. Of course, if it IS a bug...
--
from: Jonathan
Hi!
there is a bug in page_launder introduced with kernel 2.4.3-ac12.
if the swapfile is on a filesystem, then after swapping out some
pages, the system locks up. sometimes it writes an oops message.
I don't know exactly what's the problem, but with the attached
patch it works. (this is just a
Hi!
there is a bug in page_launder introduced with kernel 2.4.3-ac12.
if the swapfile is on a filesystem, then after swapping out some
pages, the system locks up. sometimes it writes an oops message.
I don't know exactly what's the problem, but with the attached
patch it works. (this is just a
- page_count(page) == (1 + !!page-buffers));
Two inversions in a row? I'd like to see that made more explicit,
otherwise it looks like a bug to me. Of course, if it IS a bug...
--
from: Jonathan Chromatix
Hi!
On Sun, 6 May 2001, Jonathan Morton wrote:
- page_count(page) == (1 + !!page-buffers));
Two inversions in a row? I'd like to see that made more explicit,
otherwise it looks like a bug to me. Of course, if it IS a bug...
it's not a bug.
if page-buffers is zero, than
At 12:07 AM +0200 2001-05-07, BERECZ Szabolcs wrote:
On Sun, 6 May 2001, Jonathan Morton wrote:
- page_count(page) == (1 + !!page-buffers));
Two inversions in a row? I'd like to see that made more explicit,
otherwise it looks like a bug to me. Of course, if it IS a
Jonathan Morton writes:
-page_count(page) == (1 + !!page-buffers));
Two inversions in a row?
It is the most straightforward way to make a '1' or '0'
integer from the NULL state of a pointer.
Later,
David S. Miller
[EMAIL PROTECTED]
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To unsubscribe from this list:
On Sun, May 06, 2001 at 09:55:26PM -0700, David S. Miller wrote:
Jonathan Morton writes:
- page_count(page) == (1 + !!page-buffers));
Two inversions in a row?
It is the most straightforward way to make a '1' or '0'
integer from the NULL state of a pointer.
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