* question on readahead and sync mounting
@ 2010-02-22 23:32 Oliver Neukum
[not found] ` <49b7c2351002221548ma5b8e81m80ac4b60a6eb9d9d@mail.gmail.com>
0 siblings, 1 reply; 3+ messages in thread
From: Oliver Neukum @ 2010-02-22 23:32 UTC (permalink / raw)
To: linux-kernel
Hi,
if a filesystem is mounted with -osync will any readahead be done for
that filesystem?
Regards
Oliver
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: question on readahead and sync mounting
[not found] ` <49b7c2351002221548ma5b8e81m80ac4b60a6eb9d9d@mail.gmail.com>
@ 2010-02-22 23:59 ` Oliver Neukum
2010-02-23 17:38 ` Jeff Moyer
0 siblings, 1 reply; 3+ messages in thread
From: Oliver Neukum @ 2010-02-22 23:59 UTC (permalink / raw)
To: GeunSik Lim; +Cc: linux-kernel
Am Dienstag, 23. Februar 2010 00:48:39 schrieben Sie:
> Please, Refer to below articles to understand readahead essentially.
>
> http://lwn.net/Articles/235164/ (On-demand readahead by corbet)
> http://kernelnewbies.org/Linux_2_6_23#head-102af265937262a7a21766ae58fddc1a29a5d8d7(
> On-demand read-ahead on Linux 2.6.23)
OK, I am looking for a way to make sure read requests on a SCSI drive
actually hit the bus after a certain event. Is there a way to do this without
tossing away the whole cache?
Regards
Oliver
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: question on readahead and sync mounting
2010-02-22 23:59 ` Oliver Neukum
@ 2010-02-23 17:38 ` Jeff Moyer
0 siblings, 0 replies; 3+ messages in thread
From: Jeff Moyer @ 2010-02-23 17:38 UTC (permalink / raw)
To: Oliver Neukum; +Cc: GeunSik Lim, linux-kernel
Oliver Neukum <oliver@neukum.org> writes:
> Am Dienstag, 23. Februar 2010 00:48:39 schrieben Sie:
>> Please, Refer to below articles to understand readahead essentially.
>>
>> http://lwn.net/Articles/235164/ (On-demand readahead by corbet)
>> http://kernelnewbies.org/Linux_2_6_23#head-102af265937262a7a21766ae58fddc1a29a5d8d7(
>> On-demand read-ahead on Linux 2.6.23)
>
> OK, I am looking for a way to make sure read requests on a SCSI drive
> actually hit the bus after a certain event. Is there a way to do this without
> tossing away the whole cache?
I'm not sure I understand what you're asking, but it sounds like you
want to do an O_DIRECT read. Open the file with O_DIRECT, then pass
a properly-aligned buffer to the read(2) call.
Cheers,
Jeff
^ permalink raw reply [flat|nested] 3+ messages in thread
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2010-02-22 23:32 question on readahead and sync mounting Oliver Neukum
[not found] ` <49b7c2351002221548ma5b8e81m80ac4b60a6eb9d9d@mail.gmail.com>
2010-02-22 23:59 ` Oliver Neukum
2010-02-23 17:38 ` Jeff Moyer
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