* Jiri Kosina <jkosina@xxxxxxx> wrote: > On Tue, 20 Oct 2009, Jiri Kosina wrote: > > > > Commit 34d76c41 introduced the update_shares_data percpu, but it ends up > > > causing problems on large ia64 machines. Specifically, ia64 is limited > > > to 64k in percpu vars and with NR_CPUS=4096, that ends up being 32k by > > > itself. It ends up causing link errors since that is how ia64 enforces > > > the 64k limit. > > > > > > I can take a deeper look at finding a workable solution but thought I'd > > > mention it in case you had ideas already. > > > > I am adding some IA64 CCs, as the failure is solely caused by the ia64 > > percpu implementation/pagefault handler optimization which requires the > > .percpu section area not be larger than 64k, which blows up with 34d76c41 > > and NR_CPUS high enoufh (due to introduction of percpu array being > > size-dependent on NR_CPUS). > > How about this one? (untested) > > > > From: Jiri Kosina <jkosina@xxxxxxx> > Subject: sched: move rq_weight data array out of .percpu > > Commit 34d76c41 introduced percpu array update_shares_data, size of which > being proportional to NR_CPUS. Unfortunately this blows up ia64 for large > NR_CPUS configuration, as ia64 allows only 64k for .percpu section. > > Fix this by allocating this array dynamically and keep only pointer to it > percpu. > > Signed-off-by: Jiri Kosina <jkosina@xxxxxxx> > --- > kernel/sched.c | 15 +++++++-------- > 1 files changed, 7 insertions(+), 8 deletions(-) Seems like an IA64 bug to me. It's _very_ easy to get more than 64K of percpu data - i'm wondering why IA64 only triggered it now? Sure lockdep/lockstat must have triggered it before. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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