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Re: Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list [message #8297 is a reply to message #7973]

Tue, 14 November 2006 05:44

Neil Brown
Messages: 6
Registered: October 2006

Junior Member

On Wednesday November 1, vvs@sw.ru wrote:
>
> Currently we have 3 type of functions that works with dentry_unused list:
>
> 1) prune_dcache(NULL) -- called from shrink_dcache_memory, frees the memory and
> requires global LRU. works well in current implementation.
> 2) prune_dcache(sb) -- called from shrink_dcache_parent(), frees subtree, LRU
> is not need here. Current implementation uses global LRU for these purposes, it
> is ineffective, and patch from Neil Brown fixes this issue.
> 3) shrink_dcache_sb() -- called when we need to free the unused dentries for
> given super block. Current implementation is not effective too, and per-sb LRU
> would be the best solution here. On the other hand patch from Neil Brown is much
> better than current implementation.
>
> In general I think that we should approve Neil Brown's patch. We (I and Kirill
> Korotaev) are ready to acknowledge it when the following remarks fill be fixed:

>
> - it seems for me list_splice() is not required inside
> prune_dcache(),

Yes, the list should be empty when we finish so you are right.

> - DCACHE_REFERENCED dentries should not be removed from private list to
> dentry_unused list, this flag should be ignored if the private list is used,

Agreed.

> - count argument should be ignored in this case too, we want to free all the
> dentries in private list,

Agreed.

> - when we shrink the whole super block we should free per-sb anonymous dentries
> too (please see Kirill Korotaev's letter)
>

Yes. Unfortunately I don't think it is as easy as it sounds.
I'll have a closer look.

> Then I'm going to prepare new patch that will enhance the shrink_dcache_sb()
> performance:
> - we can add new list head into struct superblock and use it in
> shrink_dcache_sb() instead of temporal private list. We will check is it empty
> in dput() and add the new unused dentries to per-sb list instead of
> dentry_unused list.

I think that makes sense. It means that you end up doing less work in
select_parent, because the work has already been done in dput.

How is the patch going?

NeilBrown

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[Message index]

		[Q] missing unused dentry in prune_dcache()? By: vaverin on Wed, 25 October 2006 12:30
		Re: [Q] missing unused dentry in prune_dcache()? By: vaverin on Wed, 25 October 2006 13:58
		Re: [Q] missing unused dentry in prune_dcache()? By: David Howells on Wed, 25 October 2006 14:23
		Re: [Q] missing unused dentry in prune_dcache()? By: vaverin on Thu, 26 October 2006 11:36
		Re: [Q] missing unused dentry in prune_dcache()? By: David Howells on Thu, 26 October 2006 13:25
		Re: [Q] missing unused dentry in prune_dcache()? By: vaverin on Fri, 27 October 2006 08:05
		Re: [Q] missing unused dentry in prune_dcache()? By: David Howells on Fri, 27 October 2006 10:42
		Re: [Q] missing unused dentry in prune_dcache()? By: vaverin on Fri, 27 October 2006 11:50
		Re: [Q] missing unused dentry in prune_dcache()? By: David Howells on Fri, 27 October 2006 12:11
		Re: [Q] missing unused dentry in prune_dcache()? By: vaverin on Fri, 27 October 2006 13:47
		Re: [Q] missing unused dentry in prune_dcache()? By: David Howells on Fri, 27 October 2006 14:29
		Re: [Q] missing unused dentry in prune_dcache()? By: dev on Fri, 27 October 2006 14:34
		[PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: vaverin on Fri, 27 October 2006 14:05
		Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: Andrew Morton on Fri, 27 October 2006 18:06
		Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: vaverin on Mon, 30 October 2006 14:24
		Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: Eric Dumazet on Mon, 30 October 2006 15:08
		Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: dev on Mon, 30 October 2006 15:27
		Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: Eric Dumazet on Mon, 30 October 2006 16:09
		Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: dev on Mon, 30 October 2006 15:06
		Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: David Chinner on Mon, 30 October 2006 04:24
		Re: Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: dev on Mon, 30 October 2006 06:22
		Re: Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: Neil Brown on Tue, 31 October 2006 04:38
		Re: Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: David Howells on Tue, 31 October 2006 10:40
		Re: Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: Neil Brown on Wed, 01 November 2006 06:32
		Re: Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: vaverin on Wed, 01 November 2006 13:32
		Re: Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: Neil Brown on Tue, 14 November 2006 05:44
		Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: vaverin on Tue, 14 November 2006 06:12
		Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: vaverin on Tue, 31 October 2006 13:08
		Re: Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: dev on Wed, 01 November 2006 10:48
		Re: Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: Neil Brown on Tue, 14 November 2006 04:51
		Re: Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list By: David Howells on Tue, 14 November 2006 09:29
		[PATCH 2.6.19-rc3] VFS: missing unused dentry in prune_dcache() By: vaverin on Fri, 27 October 2006 13:42
		Re: [PATCH 2.6.19-rc3] VFS: missing unused dentry in prune_dcache() By: David Howells on Fri, 27 October 2006 14:24
		Re: [Q] missing unused dentry in prune_dcache()? By: David Howells on Wed, 25 October 2006 13:51
		Re: [Q] missing unused dentry in prune_dcache()? By: vaverin on Thu, 26 October 2006 11:49
		Re: [Q] missing unused dentry in prune_dcache()? By: David Howells on Thu, 26 October 2006 12:33
		Re: [Q] missing unused dentry in prune_dcache()? By: David Howells on Thu, 26 October 2006 13:23
		Re: [Q] missing unused dentry in prune_dcache()? By: vaverin on Thu, 26 October 2006 13:58
		Re: [Q] missing unused dentry in prune_dcache()? By: David Howells on Thu, 26 October 2006 14:07
		Re: [Q] missing unused dentry in prune_dcache()? By: vaverin on Fri, 27 October 2006 06:32
		Re: [Q] missing unused dentry in prune_dcache()? By: vaverin on Fri, 27 October 2006 06:50
		Re: [Q] missing unused dentry in prune_dcache()? By: David Howells on Fri, 27 October 2006 09:36
		[Q] missing ->d_delete() in shrink_dcache_for_umount()? By: vaverin on Tue, 31 October 2006 13:24
		Re: [Q] missing ->d_delete() in shrink_dcache_for_umount()? By: David Howells on Tue, 31 October 2006 15:06

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