Messages in this thread | | | Date | Tue, 22 May 2007 09:07:37 -0700 | From | Stephane Eranian <> | Subject | Re: is TIF_NOTIFY_RESUME used? |
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Andrew,
On Tue, May 22, 2007 at 09:02:10AM -0700, Andrew Morton wrote: > On Tue, 22 May 2007 05:47:13 -0700 > Stephane Eranian <eranian@hpl.hp.com> wrote: > > > Hello, > > > > For perfmon, we need a couple of TIF bits. It seems that with 2.6.22-rc2 > > there is now a TIF_RESTORE_SIGMASK which uses the last remaining bit in the > > first 7 bits of the thread flag. Many architectures, including IA-64, rely > > on the fact that some of the TIF flags (TIF_ALL_WORKMASK or TIF_ALL_WORK) > > tested on kernel exit reside in the low 8-bit or 7-bit because they use > > instructions (such as add r1=imm8,r2 on IA-64) which operate on 8 or 7 bit > > immediate. > > > > On IA-64, adding that one perfmon flag (as bit 7) would cause some > > restructuring in the kernel exit path but also in all the lightweight syscall > > handlers. > > > > I looked at all the low order TIF flags and found that TIF_NOTIFY_RESUME > > was never set nor used anywhere in any architecture. Is that really the case? > > > > If so, we could get rid of it and free up one low-order TIF bit. > > > > My grepping argees with yours. The only place where TIF_NOTIFY_RESUME gets > altered is in ./arch/ia64/kernel/perfmon.c.
Yes, and that is with the old IA-64 code. In the new one I used a dedicated TIF flag.
Shall we just get rid of the flag, then?
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