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: Re: [PATCH 1/5] mm/readahead: Check return value of read_pages
Date: Tue, 16 Oct 2012 23:17:05 +0530 [thread overview]
Message-ID: <20121016174705.GC2826@Archie> (raw)
In-Reply-To: <20120928115405.GA1525@localhost>
[-- Attachment #1: Type: text/plain, Size: 1549 bytes --]
Hi,
* On Fri, Sep 28, 2012 at 07:54:05PM +0800, Fengguang Wu <fengguang.wu@intel.com> wrote:
>On Wed, Sep 26, 2012 at 06:55:03AM +0530, Raghavendra D Prabhu wrote:
>>
>> Hi,
>>
>>
>> * On Sat, Sep 22, 2012 at 08:43:37PM +0800, Fengguang Wu <fengguang.wu@intel.com> wrote:
>> >On Sat, Sep 22, 2012 at 04:03:10PM +0530, raghu.prabhu13@gmail.com wrote:
>> >>From: Raghavendra D Prabhu <rprabhu@wnohang.net>
>> >>
>> >>Return value of a_ops->readpage will be propagated to return value of read_pages
>> >>and __do_page_cache_readahead.
>> >
>> >That does not explain the intention and benefit of this patch..
>>
>> I noticed that force_page_cache_readahead checks return value of
>> __do_page_cache_readahead but the actual error if any is never
>> propagated.
>
>force_page_cache_readahead()'s return value, in turn, is never used by
>its callers..
Yes, it is not called by its callers, however, since it is called
in a loop, shouldn't we bail out if force_page_cache_readahead
fails once? Without the appropriate return value, it will
continue and in
force_page_cache_readahead
if (err < 0) {
ret = err;
break;
}
is never hit.
Nor does the other __do_page_cache_readahead() callers
>care about the error state. So until we find an actual user of the
>error code, I'd recommend to avoid changing the current code.
>
>Thanks,
>Fengguang
>
Regards,
--
Raghavendra Prabhu
GPG Id : 0xD72BE977
Fingerprint: B93F EBCB 8E05 7039 CD3C A4B8 A616 DCA1 D72B E977
www: wnohang.net
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next prev parent reply other threads:[~2012-10-16 17:47 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 [this message]
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
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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