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From: "Benjamin Coddington" <bcodding@redhat.com>
To: "Trond Myklebust" <trondmy@hammerspace.com>
Cc: dwysocha@redhat.com, linux-nfs@vger.kernel.org
Subject: Re: [PATCH v5 00/22] Readdir enhancements
Date: Thu, 12 Nov 2020 13:49:16 -0500	[thread overview]
Message-ID: <AF0AF7F0-EEA1-475B-987F-168724A83E60@redhat.com> (raw)
In-Reply-To: <DC49EB88-4B79-40FC-97C3-47D2A588F96C@redhat.com>

On 12 Nov 2020, at 13:39, Benjamin Coddington wrote:

> On 12 Nov 2020, at 13:26, Trond Myklebust wrote:
>
>> On Thu, 2020-11-12 at 16:51 +0000, Trond Myklebust wrote:
>>>
>>> I was going to ask you if perhaps reverting Scott's commit
>>> 07b5ce8ef2d8
>>> ("NFS: Make nfs_readdir revalidate less often") might help here?
>>> My thinking is that will trigger more cache invalidations when the
>>> directory is changing underneath us, and will now trigger uncached
>>> readdir in those situations.
>>>
>>>>
>>
>> IOW, the suggestion would be to apply something like the following on
>> top of the existing readdir patchset:
>
> I'm all for this approach, but - I'm rarely seeing the 
> mapping->nrpages == 0
> since the cache is dropped by a process in nfs_readdir() that 
> immediately
> starts filling the cache again.
>
> It would make a lot more sense to me if we could do something like 
> stash
> desc->page_index << PAGE_SHIFT in f_pos after each nfs_readdir, then 
> the
> hueristic could check f_pos >> PAGE_SHIFT > nrpages.
>
> Yes, f_pos is growing many different meanings in NFS directories, 
> maybe we
> can stash it on the directory context.

Ignore the f_pos suggestion -- iterate_dir sets it for us.. would have 
to use
a private value.

Ben


  reply	other threads:[~2020-11-12 18:49 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-10 21:37 [PATCH v5 00/22] Readdir enhancements trondmy
2020-11-10 21:37 ` [PATCH v5 01/22] NFS: Remove unnecessary inode locking in nfs_llseek_dir() trondmy
2020-11-10 21:37   ` [PATCH v5 02/22] NFS: Remove unnecessary inode lock in nfs_fsync_dir() trondmy
2020-11-10 21:37     ` [PATCH v5 03/22] NFSv4.2: condition READDIR's mask for security label based on LSM state trondmy
2020-11-10 21:37       ` [PATCH v5 04/22] NFS: Ensure contents of struct nfs_open_dir_context are consistent trondmy
2020-11-10 21:37         ` [PATCH v5 05/22] NFS: Clean up readdir struct nfs_cache_array trondmy
2020-11-10 21:37           ` [PATCH v5 06/22] NFS: Clean up nfs_readdir_page_filler() trondmy
2020-11-10 21:37             ` [PATCH v5 07/22] NFS: Clean up directory array handling trondmy
2020-11-10 21:37               ` [PATCH v5 08/22] NFS: Don't discard readdir results trondmy
2020-11-10 21:37                 ` [PATCH v5 09/22] NFS: Remove unnecessary kmap in nfs_readdir_xdr_to_array() trondmy
2020-11-10 21:37                   ` [PATCH v5 10/22] NFS: Replace kmap() with kmap_atomic() in nfs_readdir_search_array() trondmy
2020-11-10 21:37                     ` [PATCH v5 11/22] NFS: Simplify struct nfs_cache_array_entry trondmy
2020-11-10 21:37                       ` [PATCH v5 12/22] NFS: Support larger readdir buffers trondmy
2020-11-10 21:37                         ` [PATCH v5 13/22] NFS: More readdir cleanups trondmy
2020-11-10 21:37                           ` [PATCH v5 14/22] NFS: nfs_do_filldir() does not return a value trondmy
2020-11-10 21:37                             ` [PATCH v5 15/22] NFS: Reduce readdir stack usage trondmy
2020-11-10 21:37                               ` [PATCH v5 16/22] NFS: Cleanup to remove nfs_readdir_descriptor_t typedef trondmy
2020-11-10 21:37                                 ` [PATCH v5 17/22] NFS: Allow the NFS generic code to pass in a verifier to readdir trondmy
2020-11-10 21:37                                   ` [PATCH v5 18/22] NFS: Handle NFS4ERR_NOT_SAME and NFSERR_BADCOOKIE from readdir calls trondmy
2020-11-10 21:37                                     ` [PATCH v5 19/22] NFS: Improve handling of directory verifiers trondmy
2020-11-10 21:37                                       ` [PATCH v5 20/22] NFS: Optimisations for monotonically increasing readdir cookies trondmy
2020-11-10 21:37                                         ` [PATCH v5 21/22] NFS: Reduce number of RPC calls when doing uncached readdir trondmy
2020-11-10 21:37                                           ` [PATCH v5 22/22] NFS: Do uncached readdir when we're seeking a cookie in an empty page cache trondmy
2020-11-11 22:15 ` [PATCH v5 00/22] Readdir enhancements David Wysochanski
2020-11-12 11:41   ` David Wysochanski
2020-11-12 15:34     ` Guy Keren
2020-11-12 16:54       ` Trond Myklebust
2020-11-12 16:51     ` Trond Myklebust
2020-11-12 18:26       ` Trond Myklebust
2020-11-12 18:39         ` Benjamin Coddington
2020-11-12 18:49           ` Benjamin Coddington [this message]
2020-11-12 19:04           ` Trond Myklebust
2020-11-12 19:09             ` Benjamin Coddington
2020-11-12 20:23               ` Benjamin Coddington
2020-11-13 11:09                 ` Mkrtchyan, Tigran
2020-11-14 13:32         ` David Wysochanski

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