From: Raghavendra D Prabhu <raghu.prabhu13@gmail.com>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: linux-mm@kvack.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org
Subject: Re: Re: [PATCH 4/5] Move the check for ra_pages after VM_SequentialReadHint()
Date: Tue, 16 Oct 2012 23:45:21 +0530 [thread overview]
Message-ID: <20121016181521.GD2826@Archie> (raw)
In-Reply-To: <20120922124250.GB15962@localhost>
[-- Attachment #1: Type: text/plain, Size: 2042 bytes --]
Hi,
* On Sat, Sep 22, 2012 at 08:42:50PM +0800, Fengguang Wu <fengguang.wu@intel.com> wrote:
>it.rprabhu@wnohang.net>
>User-Agent: Mutt/1.5.21 (2010-09-15)
>X-Date: Sat Sep 22 18:12:50 IST 2012
>
>On Sat, Sep 22, 2012 at 04:03:13PM +0530, raghu.prabhu13@gmail.com wrote:
>> From: Raghavendra D Prabhu <rprabhu@wnohang.net>
>>
>> page_cache_sync_readahead checks for ra->ra_pages again, so moving the check
>> after VM_SequentialReadHint.
>
>Well it depends on what case you are optimizing for. I suspect there
>are much more tmpfs users than VM_SequentialReadHint users. So this
>change is actually not desirable wrt the more widely used cases.
shm/tmpfs doesn't use this function for fault. They have
shmem_fault for that. So, that shouldn't matter here. Agree?
>
>Thanks,
>Fengguang
>
>> Signed-off-by: Raghavendra D Prabhu <rprabhu@wnohang.net>
>> ---
>> mm/filemap.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/filemap.c b/mm/filemap.c
>> index 3843445..606a648 100644
>> --- a/mm/filemap.c
>> +++ b/mm/filemap.c
>> @@ -1523,8 +1523,6 @@ static void do_sync_mmap_readahead(struct vm_area_struct *vma,
>> /* If we don't want any read-ahead, don't bother */
>> if (VM_RandomReadHint(vma))
>> return;
>> - if (!ra->ra_pages)
>> - return;
>>
>> if (VM_SequentialReadHint(vma)) {
>> page_cache_sync_readahead(mapping, ra, file, offset,
>> @@ -1532,6 +1530,9 @@ static void do_sync_mmap_readahead(struct vm_area_struct *vma,
>> return;
>> }
>>
>> + if (!ra->ra_pages)
>> + return;
>> +
>> /* Avoid banging the cache line if not needed */
>> if (ra->mmap_miss < MMAP_LOTSAMISS * 10)
>> ra->mmap_miss++;
>> --
>> 1.7.12.1
>>
>> --
>> To unsubscribe, send a message with 'unsubscribe linux-mm' in
>> the body to majordomo@kvack.org. For more info on Linux MM,
>> see
Regards,
--
Raghavendra Prabhu
GPG Id : 0xD72BE977
Fingerprint: B93F EBCB 8E05 7039 CD3C A4B8 A616 DCA1 D72B E977
www: wnohang.net
[-- Attachment #2: Type: application/pgp-signature, Size: 490 bytes --]
next prev parent reply other threads:[~2012-10-16 18:15 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-22 10:33 [PATCH 0/5] Readahead fixes / improvements raghu.prabhu13
[not found] ` <cover.1348309711.git.rprabhu@wnohang.net>
2012-09-22 10:33 ` [PATCH 1/5] mm/readahead: Check return value of read_pages raghu.prabhu13
2012-09-22 12:43 ` Fengguang Wu
2012-09-26 1:25 ` Raghavendra D Prabhu
2012-09-28 11:54 ` Fengguang Wu
2012-10-16 17:47 ` Raghavendra D Prabhu
2012-10-17 2:53 ` Fengguang Wu
2012-09-22 10:33 ` [PATCH 2/5] mm/readahead: Change the condition for SetPageReadahead raghu.prabhu13
2012-09-22 12:49 ` Fengguang Wu
2012-09-26 1:29 ` Raghavendra D Prabhu
2012-09-28 11:56 ` Fengguang Wu
2012-10-16 17:42 ` Raghavendra D Prabhu
2012-10-17 2:34 ` Fengguang Wu
2012-09-22 10:33 ` [PATCH 3/5] Remove file_ra_state from arguments of count_history_pages raghu.prabhu13
2012-09-22 12:40 ` Fengguang Wu
2012-10-16 18:21 ` Raghavendra D Prabhu
2012-10-17 3:15 ` Fengguang Wu
2012-09-22 10:33 ` [PATCH 4/5] Move the check for ra_pages after VM_SequentialReadHint() raghu.prabhu13
2012-09-22 12:42 ` Fengguang Wu
2012-09-26 1:39 ` Raghavendra D Prabhu
2012-10-16 18:15 ` Raghavendra D Prabhu [this message]
2012-10-17 3:13 ` Fengguang Wu
2012-09-22 10:33 ` [PATCH 5/5] mm/readahead: Use find_get_pages instead of radix_tree_lookup raghu.prabhu13
2012-09-22 13:15 ` Fengguang Wu
2012-09-26 2:58 ` Raghavendra D Prabhu
2012-09-28 12:18 ` Fengguang Wu
2012-10-16 16:59 ` Raghavendra D Prabhu
2012-10-17 2:12 ` Fengguang Wu
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