[lkml]   [2006]   [Dec]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC] delayed allocation for ext4
On Sat, Dec 23, 2006 at 10:09:57PM +0300, Alex Tomas wrote:
> Good day,
> >>>>> David Chinner (DC) writes:
> DC> So that mean's we'll have 2 separate mechanisms for marking
> DC> pages as delalloc. XFS uses the BH_delay flag to indicate
> DC> that a buffer (block) attached to the page is using delalloc.
> well, for blocksize=pagesize we can save 56 bytes on every page.

Sure, but it means that ext4 w/ delalloc won't work on lots of

> DC> FWIW, how does this mechanism deal with block size < page size?
> DC> Don't you have to track delalloc on a block basis rather than
> DC> a page basis?
> I'm still thinking how better to deal with that w/o much code duplication.

Code duplication in ext4, or across all filesystems?

> DC> Ah, that's why you can get away with a page flag - you've ignored
> DC> the partial page delay state problem. Any plans to use the
> DC> existing method in the future so we will be able to use ext4 delalloc
> DC> on machines with a page size larger than 4k?
> what do you mean by "exsiting"? BH_delay?



Dave Chinner
Principal Engineer
SGI Australian Software Group
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: 2006-12-29 03:55    [W:0.054 / U:0.144 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site