lkml.org 
[lkml]   [2002]   [Jan]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Possible Idea with filesystem buffering.
Rik van Riel wrote:

>On Mon, 21 Jan 2002, Hans Reiser wrote:
>
>>Rik van Riel wrote:
>>
>>>On Sun, 20 Jan 2002, Hans Reiser wrote:
>>>
>
>>>Agreed on these points, but you really HAVE TO work towards
>>>flushing the page ->writepage() gets called for.
>>>
>>>Think about your typical PC, with memory in ZONE_DMA,
>>>ZONE_NORMAL and ZONE_HIGHMEM. If we are short on DMA pages
>>>we will end up calling ->writepage() on a DMA page.
>>>
>>>If the filesystem ends up writing completely unrelated pages
>>>and marking the DMA page in question referenced the VM will
>>>go in a loop until the filesystem finally gets around to
>>>making a page in the (small) DMA zone freeable ...
>>>
>>This is a bug in VM design, yes? It should signal that it needs the
>>particular page written, which probnably means that it should use
>>writepage only when it needs that particular page written,
>>
>
>That is exactly what the VM does.
>
So basically you continue to believe that one cache manager shall rule
them all, and in the darkness as to their needs, bind them.

>
>
>>and should otherwise check to see if the filesystem supports something
>>like pressure_fs_cache(), yes?
>>
>
>That's incompatible with the concept of memory zones.
>
Care to explain more?

>
>
>regards,
>
>Rik
>



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:15    [W:0.095 / U:1.776 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site