From: "Benjamin Coddington" <bcodding@redhat.com>
To: trondmy@kernel.org
Cc: linux-nfs@vger.kernel.org
Subject: Re: [PATCH 02/12] NFS: Clean up readdir struct nfs_cache_array
Date: Tue, 03 Nov 2020 09:34:06 -0500 [thread overview]
Message-ID: <37BCFCA0-58EE-499F-8A45-435C6C3925CA@redhat.com> (raw)
In-Reply-To: <ACB62869-286C-4189-9BF9-C4F622C02C73@redhat.com>
On 3 Nov 2020, at 9:09, Benjamin Coddington wrote:
> On 3 Nov 2020, at 8:35, Benjamin Coddington wrote:
>
>> On 2 Nov 2020, at 13:06, trondmy@kernel.org wrote:
>>
>>> From: Trond Myklebust <trond.myklebust@hammerspace.com>
>>>
>>> Since the 'eof_index' is only ever used as a flag, make it so.
>>> Also add a flag to detect if the page has been completely filled.
>>>
>>> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
>>> ---
>>> fs/nfs/dir.c | 66
>>> ++++++++++++++++++++++++++++++++++++++--------------
>>> 1 file changed, 49 insertions(+), 17 deletions(-)
>>>
>>> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
>>> index 67d8595cd6e5..604ebe015387 100644
>>> --- a/fs/nfs/dir.c
>>> +++ b/fs/nfs/dir.c
>>> @@ -138,9 +138,10 @@ struct nfs_cache_array_entry {
>>> };
>>>
>>> struct nfs_cache_array {
>>> - int size;
>>> - int eof_index;
>>> u64 last_cookie;
>>> + unsigned int size;
>>> + unsigned char page_full : 1,
>>> + page_is_eof : 1;
>>> struct nfs_cache_array_entry array[];
>>> };
>>>
>>> @@ -172,7 +173,6 @@ void nfs_readdir_init_array(struct page *page)
>>>
>>> array = kmap_atomic(page);
>>> memset(array, 0, sizeof(struct nfs_cache_array));
>>> - array->eof_index = -1;
>>> kunmap_atomic(array);
>>> }
>>>
>>> @@ -192,6 +192,17 @@ void nfs_readdir_clear_array(struct page *page)
>>> kunmap_atomic(array);
>>> }
>>>
>>> +static void nfs_readdir_array_set_eof(struct nfs_cache_array
>>> *array)
>>> +{
>>> + array->page_is_eof = 1;
>>> + array->page_full = 1;
>>> +}
>>> +
>>> +static bool nfs_readdir_array_is_full(struct nfs_cache_array
>>> *array)
>>> +{
>>> + return array->page_full;
>>> +}
>>> +
>>> /*
>>> * the caller is responsible for freeing qstr.name
>>> * when called by nfs_readdir_add_to_array, the strings will be
>>> freed in
>>> @@ -213,6 +224,23 @@ int nfs_readdir_make_qstr(struct qstr *string,
>>> const char *name, unsigned int le
>>> return 0;
>>> }
>>>
>>> +/*
>>> + * Check that the next array entry lies entirely within the page
>>> bounds
>>> + */
>>> +static int nfs_readdir_array_can_expand(struct nfs_cache_array
>>> *array)
>>> +{
>>> + struct nfs_cache_array_entry *cache_entry;
>>> +
>>> + if (array->page_full)
>>> + return -ENOSPC;
>>> + cache_entry = &array->array[array->size + 1];
>>> + if ((char *)cache_entry - (char *)array > PAGE_SIZE) {
>>> + array->page_full = 1;
>>> + return -ENOSPC;
>>> + }
>>> + return 0;
>>> +}
>>> +
>>
>> I think we could do this calculation at compile-time instead of doing
>> it for
>> each entry, for dubious nominal gains..
>
> and doing so might allow us to detect the case where the array is full
> before doing another RPC that we'll discard.
And you handle this case in patch 4/12...
Ben
next prev parent reply other threads:[~2020-11-03 14:36 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-02 18:06 [PATCH 00/12] Readdir enhancements trondmy
2020-11-02 18:06 ` [PATCH 01/12] NFS: Ensure contents of struct nfs_open_dir_context are consistent trondmy
2020-11-02 18:06 ` [PATCH 02/12] NFS: Clean up readdir struct nfs_cache_array trondmy
2020-11-02 18:06 ` [PATCH 03/12] NFS: Clean up nfs_readdir_page_filler() trondmy
2020-11-02 18:06 ` [PATCH 04/12] NFS: Clean up directory array handling trondmy
2020-11-02 18:06 ` [PATCH 05/12] NFS: Don't discard readdir results trondmy
2020-11-02 18:06 ` [PATCH 06/12] NFS: Remove unnecessary kmap in nfs_readdir_xdr_to_array() trondmy
2020-11-02 18:06 ` [PATCH 07/12] NFS: Replace kmap() with kmap_atomic() in nfs_readdir_search_array() trondmy
2020-11-02 18:06 ` [PATCH 08/12] NFS: Simplify struct nfs_cache_array_entry trondmy
2020-11-02 18:06 ` [PATCH 09/12] NFS: Support larger readdir buffers trondmy
2020-11-02 18:06 ` [PATCH 10/12] NFS: More readdir cleanups trondmy
2020-11-02 18:06 ` [PATCH 11/12] NFS: nfs_do_filldir() does not return a value trondmy
2020-11-02 18:06 ` [PATCH 12/12] NFS: Reduce readdir stack usage trondmy
2020-11-03 14:18 ` [PATCH 03/12] NFS: Clean up nfs_readdir_page_filler() Benjamin Coddington
2020-11-03 14:24 ` Benjamin Coddington
2020-11-03 13:35 ` [PATCH 02/12] NFS: Clean up readdir struct nfs_cache_array Benjamin Coddington
2020-11-03 14:09 ` Benjamin Coddington
2020-11-03 14:34 ` Benjamin Coddington [this message]
2020-11-02 20:40 ` [PATCH 00/12] Readdir enhancements David Wysochanski
2020-11-02 21:32 ` Trond Myklebust
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