* writepage
@ 2004-03-01 20:27 Anand Eswaran
2004-03-01 20:33 ` writepage Raghu R. Arur
0 siblings, 1 reply; 5+ messages in thread
From: Anand Eswaran @ 2004-03-01 20:27 UTC (permalink / raw)
To: linux-mm
Hi :
I have quick question reg Linux 2.4.18, Ive tried to understand the code
but am pretty confused:
In the typical malloc execution-path, the page is added to swap and it's
pte_chain is unmapped after which the writepage() is executed. However I
notice that *after* the writepage(), the page->buffers is NON_NULL.
Is this supposed to happen? I thought the writepage function flushed the
page to swap, so why are there residual buffers?
Thanks,
----
Anand.
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: writepage
2004-03-01 20:27 writepage Anand Eswaran
@ 2004-03-01 20:33 ` Raghu R. Arur
2004-03-01 20:59 ` writepage Anand Eswaran
0 siblings, 1 reply; 5+ messages in thread
From: Raghu R. Arur @ 2004-03-01 20:33 UTC (permalink / raw)
To: Anand Eswaran; +Cc: linux-mm
The page is added to the swap cache by add_to_swap_cache and not by
writepage.
writepage() (swap_writepage() in this case) prepares the page to write to
the swap disk by creating buffers and submits the page to the disk. So
page->buffers will be NON_NULL.
Raghu.
On Mon, 1 Mar 2004, Anand Eswaran wrote:
> Hi :
>
> I have quick question reg Linux 2.4.18, Ive tried to understand the code
> but am pretty confused:
>
> In the typical malloc execution-path, the page is added to swap and it's
> pte_chain is unmapped after which the writepage() is executed. However I
> notice that *after* the writepage(), the page->buffers is NON_NULL.
>
> Is this supposed to happen? I thought the writepage function flushed the
> page to swap, so why are there residual buffers?
>
> Thanks,
> ----
> Anand.
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"aart@kvack.org"> aart@kvack.org </a>
>
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: writepage
2004-03-01 20:33 ` writepage Raghu R. Arur
@ 2004-03-01 20:59 ` Anand Eswaran
2004-03-01 21:05 ` writepage Anand Eswaran
0 siblings, 1 reply; 5+ messages in thread
From: Anand Eswaran @ 2004-03-01 20:59 UTC (permalink / raw)
To: Raghu R. Arur; +Cc: linux-mm
In that case, it seems to me that during the next pass of the launder
loop, the loop by definition cannot have a (page->mapping) value of NULL
because it has been added to the swapcache in the previous pass.
Is that true?
-----
Anand.
On Mon, 1 Mar 2004, Raghu R. Arur wrote:
>
> The page is added to the swap cache by add_to_swap_cache and not by
> writepage.
>
> writepage() (swap_writepage() in this case) prepares the page to write to
> the swap disk by creating buffers and submits the page to the disk. So
> page->buffers will be NON_NULL.
>
> Raghu.
>
> On Mon, 1 Mar 2004, Anand Eswaran wrote:
>
> > Hi :
> >
> > I have quick question reg Linux 2.4.18, Ive tried to understand the code
> > but am pretty confused:
> >
> > In the typical malloc execution-path, the page is added to swap and it's
> > pte_chain is unmapped after which the writepage() is executed. However I
> > notice that *after* the writepage(), the page->buffers is NON_NULL.
> >
> > Is this supposed to happen? I thought the writepage function flushed the
> > page to swap, so why are there residual buffers?
> >
> > Thanks,
> > ----
> > Anand.
> >
> > --
> > To unsubscribe, send a message with 'unsubscribe linux-mm' in
> > the body to majordomo@kvack.org. For more info on Linux MM,
> > see: http://www.linux-mm.org/ .
> > Don't email: <a href=mailto:"aart@kvack.org"> aart@kvack.org </a>
> >
>
>
>
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: writepage
2004-03-01 20:59 ` writepage Anand Eswaran
@ 2004-03-01 21:05 ` Anand Eswaran
2004-03-01 21:10 ` writepage Raghu R. Arur
0 siblings, 1 reply; 5+ messages in thread
From: Anand Eswaran @ 2004-03-01 21:05 UTC (permalink / raw)
To: Raghu R. Arur; +Cc: linux-mm
Sorry I meant for a given page , during the next pass, when the
page->buffers is NON_NULL and is released, by definition the page cannot
have a null mapping because it would have been added in the swapcache
previous pass. Is that true?
Thanks,
----
Anand.
On Mon, 1 Mar 2004, Anand Eswaran wrote:
> In that case, it seems to me that during the next pass of the launder
> loop, the loop by definition cannot have a (page->mapping) value of NULL
> because it has been added to the swapcache in the previous pass.
>
> Is that true?
> -----
> Anand.
>
>
>
> On Mon, 1 Mar 2004, Raghu R. Arur wrote:
>
> >
> > The page is added to the swap cache by add_to_swap_cache and not by
> > writepage.
> >
> > writepage() (swap_writepage() in this case) prepares the page to write to
> > the swap disk by creating buffers and submits the page to the disk. So
> > page->buffers will be NON_NULL.
> >
> > Raghu.
> >
> > On Mon, 1 Mar 2004, Anand Eswaran wrote:
> >
> > > Hi :
> > >
> > > I have quick question reg Linux 2.4.18, Ive tried to understand the code
> > > but am pretty confused:
> > >
> > > In the typical malloc execution-path, the page is added to swap and it's
> > > pte_chain is unmapped after which the writepage() is executed. However I
> > > notice that *after* the writepage(), the page->buffers is NON_NULL.
> > >
> > > Is this supposed to happen? I thought the writepage function flushed the
> > > page to swap, so why are there residual buffers?
> > >
> > > Thanks,
> > > ----
> > > Anand.
> > >
> > > --
> > > To unsubscribe, send a message with 'unsubscribe linux-mm' in
> > > the body to majordomo@kvack.org. For more info on Linux MM,
> > > see: http://www.linux-mm.org/ .
> > > Don't email: <a href=mailto:"aart@kvack.org"> aart@kvack.org </a>
> > >
> >
> >
> >
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"aart@kvack.org"> aart@kvack.org </a>
>
>
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: writepage
2004-03-01 21:05 ` writepage Anand Eswaran
@ 2004-03-01 21:10 ` Raghu R. Arur
0 siblings, 0 replies; 5+ messages in thread
From: Raghu R. Arur @ 2004-03-01 21:10 UTC (permalink / raw)
To: Anand Eswaran; +Cc: linux-mm
Yes a page that is in swap cache and on which a rw_swap_page() is done,
will have both buffers and mapping NON_NULL..
On Mon, 1 Mar 2004, Anand Eswaran wrote:
>
> Sorry I meant for a given page , during the next pass, when the
> page->buffers is NON_NULL and is released, by definition the page cannot
> have a null mapping because it would have been added in the swapcache
> previous pass. Is that true?
>
> Thanks,
> ----
> Anand.
>
> On Mon, 1 Mar 2004, Anand Eswaran wrote:
>
> > In that case, it seems to me that during the next pass of the launder
> > loop, the loop by definition cannot have a (page->mapping) value of NULL
> > because it has been added to the swapcache in the previous pass.
> >
> > Is that true?
> > -----
> > Anand.
> >
> >
> >
> > On Mon, 1 Mar 2004, Raghu R. Arur wrote:
> >
> > >
> > > The page is added to the swap cache by add_to_swap_cache and not by
> > > writepage.
> > >
> > > writepage() (swap_writepage() in this case) prepares the page to write to
> > > the swap disk by creating buffers and submits the page to the disk. So
> > > page->buffers will be NON_NULL.
> > >
> > > Raghu.
> > >
> > > On Mon, 1 Mar 2004, Anand Eswaran wrote:
> > >
> > > > Hi :
> > > >
> > > > I have quick question reg Linux 2.4.18, Ive tried to understand the code
> > > > but am pretty confused:
> > > >
> > > > In the typical malloc execution-path, the page is added to swap and it's
> > > > pte_chain is unmapped after which the writepage() is executed. However I
> > > > notice that *after* the writepage(), the page->buffers is NON_NULL.
> > > >
> > > > Is this supposed to happen? I thought the writepage function flushed the
> > > > page to swap, so why are there residual buffers?
> > > >
> > > > Thanks,
> > > > ----
> > > > Anand.
> > > >
> > > > --
> > > > To unsubscribe, send a message with 'unsubscribe linux-mm' in
> > > > the body to majordomo@kvack.org. For more info on Linux MM,
> > > > see: http://www.linux-mm.org/ .
> > > > Don't email: <a href=mailto:"aart@kvack.org"> aart@kvack.org </a>
> > > >
> > >
> > >
> > >
> > --
> > To unsubscribe, send a message with 'unsubscribe linux-mm' in
> > the body to majordomo@kvack.org. For more info on Linux MM,
> > see: http://www.linux-mm.org/ .
> > Don't email: <a href=mailto:"aart@kvack.org"> aart@kvack.org </a>
> >
> >
>
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^ permalink raw reply [flat|nested] 5+ messages in thread
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2004-03-01 20:27 writepage Anand Eswaran
2004-03-01 20:33 ` writepage Raghu R. Arur
2004-03-01 20:59 ` writepage Anand Eswaran
2004-03-01 21:05 ` writepage Anand Eswaran
2004-03-01 21:10 ` writepage Raghu R. Arur
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