Messages in this thread | | | Date | Fri, 24 Dec 2010 21:18:02 -0500 | From | Jeff Mahoney <> | Subject | Re: taskstats alignment... |
| |
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
On 12/24/2010 04:16 PM, Dan Carpenter wrote: > On Fri, Dec 24, 2010 at 01:45:29PM -0500, Jeff Mahoney wrote: > v> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA1 >> >> On 12/23/2010 12:30 PM, David Miller wrote: >>> >>> Re: commit 4be2c95d1f7706ca0e74499f2bd118e1cee19669 >>> >>> Pretty much every 64-bit architecture other than >>> powerpc64 and x86-64 needs that code, not just >>> IA64. >>> >>> Better check would be: >>> >>> CONFIG_64BIT && !CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS >>> >>> Otherwise we'll be twiddling that ifdef endlessly as each >>> and every other 64-bit platform bumps into this issue. >>> >>> So please could you change this to use a more sane check? >> >> I don't have an objection to it, but I've been pushing that we make the >> change universal from the beginning of the discussion. >> >> The issue is that it causes breakage on apps that aren't following the >> interface properly. iotop, in particular, has hard-coded offsets into >> the packet to fish out the taskstats structure. >> >> So, if the goal of not breaking x86_64 is good enough, I'm fine with >> this change. > > Didn't you say something along the lines that if they don't have > CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS then there is a warning message > printed in dmesg? I thought that was what prompted you to change the > alignment in the first place. It sound like those arches are already > broken so David's suggestion would be a clear improvement over the > current code.
Yes, that is the original reason for the patch. The discussion was surrounding which arches to break, since I made it universal. Changing it to CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS (didn't know that existed before) makes sense.
> BTW, since you're redoing the patch, it would be good if you pasted the > warning message into the changelog.
Ok, that's easy enough.
- -Jeff
- -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org/
iEYEARECAAYFAk0VVFgACgkQLPWxlyuTD7JD2gCgi99mSqA29g5k9b9yj7od67mk rkAAnR5Stz8fY4eYZbRJetz+fyH8D3iz =zgux -----END PGP SIGNATURE-----
| |