[lkml]   [2006]   [Jul]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] mm: moving dirty pages balancing to pdfludh entirely
Ananiev, Leonid I writes:
> Nikita Danilov wtites:
> > performs page-out even if queue is congested.
> Yes. If user thread which generates dirty pages need in
> reclaimed memory it consider own dirty page as candidate for page-out.
> It functions as before patching.
> > Intent of this is to throttle writers.
> I suppose you means dirtier or write(2) caller but not writepage()
> caller. The dirtier is throttled with backing_dev_info logic as before
> patching.

I meant ->writepages() used by balance_dirty_pages(), see below.

> While pdflush thread sorts pages for page-out it does not
> consider as a candidate a page to be written with congested queue.
> Pdflush thread functions as before patching. Pdflush tends to make pages
> un-dirty without overload memory or IO and it is not need to let pdflush

This assumption is valid for ext2, where ->writepages() simply sends
pages to the storage, but other file systems (like reiser4) do a *lot*
of work in ->writepages() path, allocating quite an amount of memory
before starting write-out. With your patch, this work is done from
pdflush, and won't be throttled by may_write_to_queue() check, thus
increasing a risk of allocation failure.

> do page-out with congested queue as you have proposed.
> Leonid

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2006-07-04 12:12    [W:0.031 / U:0.108 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site