Re: [PATCH v1 0/4] Kill the time spent in patch_instruction()

Argh !! Looks like I sent an old already applied series nested in the 
new one.

Ignore those x/4 patches, only look at the x/6 ones.


Le 27/09/2022 à 16:33, Christophe Leroy a écrit :

This series reduces by 70% the time required to activate
ftrace on an 8xx with CONFIG_STRICT_KERNEL_RWX.

Measure is performed in function ftrace_replace_code() using mftb()
around the loop.

With the series,
- Without CONFIG_STRICT_KERNEL_RWX, 416000 TB ticks are measured.
- With CONFIG_STRICT_KERNEL_RWX, 546000 TB ticks are measured.

Before this series,
- Without CONFIG_STRICT_KERNEL_RWX, 427000 TB ticks are measured.
- With CONFIG_STRICT_KERNEL_RWX, 1744000 TB ticks are measured.

Before the series, CONFIG_STRICT_KERNEL_RWX multiplies the time
required for ftrace activation by more than 4.

With the series, CONFIG_STRICT_KERNEL_RWX increases the time
required for ftrace activation by only 30%

Christophe Leroy (4):
   powerpc/code-patching: Don't call is_vmalloc_or_module_addr() without
     CONFIG_MODULES
   powerpc/code-patching: Speed up page mapping/unmapping
   powerpc/code-patching: Use jump_label for testing freed initmem
   powerpc/code-patching: Use jump_label to check if poking_init() is
     done

  arch/powerpc/include/asm/code-patching.h |  2 ++
  arch/powerpc/lib/code-patching.c         | 37 +++++++++++++++---------
  arch/powerpc/mm/mem.c                    |  2 ++
  3 files changed, 28 insertions(+), 13 deletions(-)