-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 6/4/14, 12:07 PM, Jean Delvare wrote:
Hi Cristian,
Le Tuesday 27 May 2014 à 11:49 -0400, Cristian Rodríguez a écrit :
Just out of curiosity, why SUSE kernels default to CONFIG_SLAB and not CONFIG_SLUB ? I just checked the rest of current distribution world and everyone else takes the kernel default.
I am assuming there is a reason for this, that it is intentional and not a oversight where somebody forgot changing the configuration...
The topic was already brought up for discussion in July 2008: http://lists.opensuse.org/opensuse-kernel/2008-07/msg00014.html
While SLUB was already the default for one year, Jeff did not think it was the right time to switch. The lack of explanation in the upstream commit that changed the default may explain it :-(
Almost 6 years later, I guess we can revisit this. While I am not familiar with SLAB vs. SLUB, I see that: * There must be a reason why SLUB is the default, and there is nothing extraordinary about openSUSE that I can think of that would justify not sticking to that default. * Using what the majority is using should make it less likely to hit a bug. And if there is a bug, it is likely to be fixed much faster.
So unless someone can provide a good reason why we should stick to SLAB, I vote for switching to SLUB.
I vote against unless there's a compelling reason to change it. Sometimes the default changes upstream because it's new and shiny and more or less working. It's a way to improve test coverage. The problem is that test coverage in most cases just means that it doesn't crash. I asked Mel about this on IRC a few days ago and the response was along the lines of "it's the devil we know." He also mentioned that he recalled the last time he looked into it there were still network performance regressions that hadn't been fixed yet. That may have changed since the last time he looked at it, but without confirmation, I'm going to assume they're still there. So far I haven't seen a compelling reason to change it other than "it's the default." I'd suggest that anyone pushing to change the choice in allocator be willing to actually do that testing and post the numbers and breadth of the test coverage before we do change it. - -Jeff - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.19 (Darwin) iQIcBAEBAgAGBQJTj0cVAAoJEB57S2MheeWyV24P/1ar+lKArQM70E+cv+73rSb0 C1PDWell1STTIoE6yWOnDGoi+E59RpIvJ9bg+HEyzrmr6g0rUc5SpvfZarlBezur JkrekwbjSRBKMwaTBKmw/kZP2QvocYHu9eMvCFioD1fuckrZA8sZ2Uq5EF450eIB YDLSvb5oxh37GwSUoZnN0NPdt1s0CsVqSjRiQR+BQ+61Kt4us+VrxOxa+ZtWT08a BVfi0X15LCPKkVdsjED65l16zU+Y5iiaY1KNF6XioZc9wB8kgwya0cD2hNy44YaL nEI10p7TwiwbcqHPLkFJRMj5k+TCgsIhy7CPi/geCLil98MbhKcs1DRU9WXzSSnt PY3cOGCvsFxN6DrYDO95KCzuMrLrqE2FSU5wIn/M6/KTibtRk3h0Hmg8el80Tpz7 mC1qH3W+e65Plh3UO1lFrtj4jRsvdOQiEC86wwfmjGftRc2bjMUx3HlrNN0kIo/C tfnM4EJoe97yxFeZcE75QX+Eqg9aoMICr5xexzXvxq0v5CbFgSLxPW+NJTWq1VWK Pg69C/12wBrmFDWrBVdBtlAIfzlsuPGkDCEa+hP573jjobQACsR8N3gQB698zkhX 4m58oCUX/yK34cEIb7jBvtM3pzW8LxBpt1jFw4gQMJhWNbYxN4/3MDqJG32TgSR8 VfGCTEE6dyO0P0bFHsAn =zzp9 -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org