Messages in this thread | | | Date | Fri, 29 Aug 2008 12:10:08 -0400 | From | Gregory Haskins <> | Subject | Re: [PATCH] seqlock: serialize against writers |
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Andi Kleen wrote: > Gregory Haskins <ghaskins@novell.com> writes: > > >> *Patch submitted for inclusion in PREEMPT_RT 26-rt4. Applies to 2.6.26.3-rt3* >> >> Hi Ingo, Steven, Thomas, >> Please consider for -rt4. This fixes a nasty deadlock on my systems under >> heavy load. >> > > Does this even work under x86-64? x86-64 uses seqlocks in user space > in its vsyscalls. And read_lock() definitely doesn't work there because > it writes. > > You would need at least to disable vsyscall gettimeofday(), making > it much much slower. > > Perhaps you tested on one of the systems where the vsyscalls need > to fallback for other reasons? (e.g. one using pmtimer for timing). > > -Andi >
Im running it on a x86_64 box as we speak. How can I tell if there is a certain mode that is permitting this?
-Greg
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