On 05/11/2025 02:46, Ritesh Harjani (IBM) wrote:

Kevin Brodsky [off-list ref] writes:

quoted

From: Alexander Gordeev <agordeev@linux.ibm.com>

Since commit b9ef323ea168 ("powerpc/64s: Disable preemption in hash
lazy mmu mode") a task can not be preempted while in lazy MMU mode.
Therefore, the batch re-activation code is never called, so remove it.

Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Kevin Brodsky <redacted>
---
 arch/powerpc/include/asm/thread_info.h |  2 --
 arch/powerpc/kernel/process.c          | 25 -------------------------
 2 files changed, 27 deletions(-)

Since the commit referenced in above disables the preemption in
arch_enter_lazy_mmu(), so the expectation is that we will never be
context switched while in lazy_mmu, hence the code changes in
switch_to() around __flush_tlb_pending() should ideally never be called.

Correct, that's the idea.

With this analysis - the patch looks good to me. I will give this entire
patch series a try on Power HW with Hash mmu too (which uses lazy mmu and
let you know the results of that)!

That'd be very appreciated, thanks a lot!

For this patch please feel free to add:
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>


CC: Venkat who also runs CI on linux Power HW for upstream testing :)

Ack, will Cc you both in the next version.

- Kevin