2008-04-28 19:07:38

by Manish Katiyar

Subject: Using tgid instead of pid in ext3_find_near()

Hi,

In the function ext*_find_near() we are using pid to have the locality
of the blocks for the files which have same functionality. Shouldn't
we be using "current->tgid" here instead ??

410 static ext3_fsblk_t ext3_find_near(struct inode *inode, Indirect *ind)
411 {
.........
........
433 colour = (current->pid % 16) *
434 (EXT3_BLOCKS_PER_GROUP(inode->i_sb) / 16);
........

--
Thanks & Regards,
********************************************
Manish Katiyar ( http://mkatiyar.googlepages.com )
3rd Floor, Fair Winds Block
EGL Software Park
Off Intermediate Ring Road
Bangalore 560071, India
***********************************************

2008-04-29 00:57:06

by Mulyadi Santosa

Subject: Re: Using tgid instead of pid in ext3_find_near()

Ehmmm....

On Tue, Apr 29, 2008 at 2:07 AM, Manish Katiyar <[email protected]> wrote:
> Hi,
>
> In the function ext*_find_near() we are using pid to have the locality
> of the blocks for the files which have same functionality. Shouldn't
> we be using "current->tgid" here instead ??
>
> 410 static ext3_fsblk_t ext3_find_near(struct inode *inode, Indirect *ind)
> 411 {
> .........
> ........
> 433 colour = (current->pid % 16) *
> 434 (EXT3_BLOCKS_PER_GROUP(inode->i_sb) / 16);
> ........

Because each threads even on same thread group doesn't need to share
open file descriptors?

regards,

Mulyadi.

2008-04-29 04:23:59

by Manish Katiyar

Subject: Re: Using tgid instead of pid in ext3_find_near()

On Tue, Apr 29, 2008 at 6:27 AM, Mulyadi Santosa
<[email protected]> wrote:
> Ehmmm....
>
>
> On Tue, Apr 29, 2008 at 2:07 AM, Manish Katiyar <[email protected]> wrote:
> > Hi,
> >
> > In the function ext*_find_near() we are using pid to have the locality
> > of the blocks for the files which have same functionality. Shouldn't
> > we be using "current->tgid" here instead ??
> >
> > 410 static ext3_fsblk_t ext3_find_near(struct inode *inode, Indirect *ind)
> > 411 {
> > .........
> > ........
> > 433 colour = (current->pid % 16) *
> > 434 (EXT3_BLOCKS_PER_GROUP(inode->i_sb) / 16);
> > ........
>
> Because each threads even on same thread group doesn't need to share
> open file descriptors?

Hi Mulyadi,

It's not about the open file descriptors. The idea behind putting this
is to put all the blocks of same process (which may be functionally
related) nearby in the blockgroup for locality. So I think we should
be using tgid instead of pid.

Thanks

>
> regards,
>
> Mulyadi.
>



--
Thanks & Regards,
********************************************
Manish Katiyar ( http://mkatiyar.googlepages.com )
3rd Floor, Fair Winds Block
EGL Software Park
Off Intermediate Ring Road
Bangalore 560071, India
***********************************************