Hello,
> > > Why do you need to expose this Cell-specific feature into generic code?
> > >
> > > Can't you hide this inside the arch code by using the pfm_arch_*()
> > callbacks?
> >
> > No.
> > In this patch, I want to avoid setting TIF_PERFMON_CTXSW to the task flag
> > when cell_spe_follow flag is set.
> > I couln't hide this change in pfmon_arch_load_context(),
> > because it is called before set_task_thread_flag().
> >
> Ok, I see your problem now.
>
> We have 2 solutions:
> - move pfm_arch_load_context() AFTER the TIF_PERFMON_CTXSW
> - add a generic flag (context_flags) that pfm_arch_load_context()
> can set to tell the generic code NOT to set TIF_PERFMON_CTXSW
>
> I'd rather not move pfm_arch_load_context() because there would be
> more code to undo if it ever fails.
>
> The 2nd solution is not too pretty either because it relies on the
> position of pfm_arch_load_context(). However, we could move
> setting that flag to pfm_arch_create_context() given that you've added
> the context-level flag for SPE_FOLLOW. Could you try that?
How about this?
Is this the change which you expected?
-----------------------------------------------
This patch adds not_dflt_ctxsw flag to context flags.
This flag is used not to set TIF_PERFMON_CTXSW.
Signed-off-by: Takashi Yamamoto <[EMAIL PROTECTED]>
---
arch/powerpc/perfmon/perfmon_cell.c | 2 ++
include/asm-powerpc/perfmon.h | 8 ++++++++
include/linux/perfmon_kern.h | 3 ++-
perfmon/perfmon_attach.c | 4 +++-
4 files changed, 15 insertions(+), 2 deletions(-)
--- a/arch/powerpc/perfmon/perfmon_cell.c
+++ b/arch/powerpc/perfmon/perfmon_cell.c
@@ -1220,6 +1220,8 @@ static void pfm_cell_get_ovfl_pmds(struc
**/
static int pfm_cell_create_context(struct pfm_context *ctx, u32 ctx_flags)
{
+ ctx->flags.not_dflt_ctxsw =
+ (ctx_flags & PFM_FL_CELL_SPE_FOLLOW) ? 1:0;
return 0;
}
--- a/include/asm-powerpc/perfmon.h
+++ b/include/asm-powerpc/perfmon.h
@@ -31,4 +31,12 @@
#define PFM_ARCH_MAX_PMCS (256+64) /* 256 HW 64 SW */
#define PFM_ARCH_MAX_PMDS (256+64) /* 256 HW 64 SW */
+/*
+ * context flags (ctx_flags)
+ *
+ * bits[00-15]: generic flags
+ * bits[16-31]: arch-specific flags
+ */
+#define PFM_FL_CELL_SPE_FOLLOW 0x10000
+
#endif /* _ASM_POWERPC_PERFMON_H_ */
--- a/include/linux/perfmon_kern.h
+++ b/include/linux/perfmon_kern.h
@@ -118,7 +118,8 @@ struct pfm_context_flags {
unsigned int can_restart:8; /* allowed to issue a PFM_RESTART */
unsigned int reset_count:8; /* number of pending resets */
unsigned int is_self:1; /* per-thread and self-montoring */
- unsigned int reserved:5; /* for future use */
+ unsigned int not_dflt_ctxsw:1; /* TIF_PERFMON_CTXSW is not set */
+ unsigned int reserved:4; /* for future use */
};
/*
--- a/perfmon/perfmon_attach.c
+++ b/perfmon/perfmon_attach.c
@@ -240,7 +240,9 @@ static int pfm_load_ctx_thread(struct pf
*/
pfm_set_pmu_owner(ctx->task, ctx);
}
- set_tsk_thread_flag(task, TIF_PERFMON_CTXSW);
+
+ if (!ctx->flags.not_dflt_ctxsw)
+ set_tsk_thread_flag(task, TIF_PERFMON_CTXSW);
/*
* reset pending work
-------------------------------------------------------------------------
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