LinuxLists.cc - Regression introduced by commit "lib/bitmap.c: speed up bitmap_find_free

2013-05-31 06:45:22

Subject: Regression introduced by commit "lib/bitmap.c: speed up bitmap_find_free_region"

Hi,

While testing MFC decoder on Exynos machines, I encountered some
memory allocation errors due to failure of dma_alloc_coherent().
File: drivers/media/platform/s5p-mfc/s5p_mfc_ctrl.c Line: 38.

Git bisect pointed me to the following commit as the first bad commit
(linux-next tree of 20130531):

commit 3d5272d9b289cd0930b2ea9984406d757a72f4dd
Author: Chanho Min <[email protected]>
Date: Thu May 23 10:37:28 2013 +1000
lib/bitmap.c: speed up bitmap_find_free_region

Reverting this (and the commit 197e1cf7
("ib-bitmapc-speed-up-bitmap_find_free_region-fix") ) fixes this
issue.

Looks like some regression has been introduced by the above patch?

---
With warm regards,
Sachin

2013-05-31 19:05:51

by Andrew Morton

[permalink] [raw]

Subject: Re: Regression introduced by commit "lib/bitmap.c: speed up bitmap_find_free_region"

On Fri, 31 May 2013 12:15:10 +0530 Sachin Kamat <[email protected]> wrote:

> Hi,
>
> While testing MFC decoder on Exynos machines, I encountered some
> memory allocation errors due to failure of dma_alloc_coherent().
> File: drivers/media/platform/s5p-mfc/s5p_mfc_ctrl.c Line: 38.
>
> Git bisect pointed me to the following commit as the first bad commit
> (linux-next tree of 20130531):
>
> commit 3d5272d9b289cd0930b2ea9984406d757a72f4dd
> Author: Chanho Min <[email protected]>
> Date: Thu May 23 10:37:28 2013 +1000
> lib/bitmap.c: speed up bitmap_find_free_region
>
> Reverting this (and the commit 197e1cf7
> ("ib-bitmapc-speed-up-bitmap_find_free_region-fix") ) fixes this
> issue.
>
> Looks like some regression has been introduced by the above patch?

Thanks. I dropped the patches for now, to minimise linux-next
breakage. Hopefully we'll be able to identify and fix this at a later
time.

2013-06-03 06:32:08

by Stephen Rothwell

[permalink] [raw]

Subject: Re: Regression introduced by commit "lib/bitmap.c: speed up bitmap_find_free_region"

Hi Andrew,

On Fri, 31 May 2013 12:05:42 -0700 Andrew Morton <[email protected]> wrote:
>
> On Fri, 31 May 2013 12:15:10 +0530 Sachin Kamat <[email protected]> wrote:
>
> > While testing MFC decoder on Exynos machines, I encountered some
> > memory allocation errors due to failure of dma_alloc_coherent().
> > File: drivers/media/platform/s5p-mfc/s5p_mfc_ctrl.c Line: 38.
> >
> > Git bisect pointed me to the following commit as the first bad commit
> > (linux-next tree of 20130531):
> >
> > commit 3d5272d9b289cd0930b2ea9984406d757a72f4dd
> > Author: Chanho Min <[email protected]>
> > Date: Thu May 23 10:37:28 2013 +1000
> > lib/bitmap.c: speed up bitmap_find_free_region
> >
> > Reverting this (and the commit 197e1cf7
> > ("ib-bitmapc-speed-up-bitmap_find_free_region-fix") ) fixes this
> > issue.
> >
> > Looks like some regression has been introduced by the above patch?
>
> Thanks. I dropped the patches for now, to minimise linux-next
> breakage. Hopefully we'll be able to identify and fix this at a later
> time.

I removed those 2 patches from the akpm tree in linux-next today as well.
--
Cheers,
Stephen Rothwell [email protected]

Attachments:

(No filename) (1.17 kB)
(No filename) (836.00 B)
Download all attachments