Re: [PATCH 2/4] mm/mprotect: move softleaf code out of the main function

David Hildenbrand (Arm)
2026-03-20T10:07:35Z

On 3/20/26 11:04, Pedro Falcato wrote:
> On Thu, Mar 19, 2026 at 10:33:47PM +0100, David Hildenbrand (Arm) wrote:
>> On 3/19/26 19:31, Pedro Falcato wrote:
>>> Move softleaf change_pte_range code into a separate function. This makes
>>> the change_pte_range() function (or where it inlines) a good bit
>>> smaller. Plus it lessens cognitive load when reading through the
>>> function.
>>>
>>> Signed-off-by: Pedro Falcato <pfalcato@suse.de>
>>> ---
>>> mm/mprotect.c | 128 +++++++++++++++++++++++++++-----------------------
>>> 1 file changed, 68 insertions(+), 60 deletions(-)
>>>
>>> diff --git a/mm/mprotect.c b/mm/mprotect.c
>>> index 1bd0d4aa07c2..8d4fa38a8a26 100644
>>> --- a/mm/mprotect.c
>>> +++ b/mm/mprotect.c
>>> @@ -211,6 +211,73 @@ static void set_write_prot_commit_flush_ptes(struct vm_area_struct *vma,
>>> commit_anon_folio_batch(vma, folio, page, addr, ptep, oldpte, ptent, nr_ptes, tlb);
>>> }
>>>
>>> +static noinline long change_pte_softleaf(struct vm_area_struct *vma,
>>
>> Why the noinline? This sounds like something that works good on some
>> CPUs and bad on others, no?
>>
>
> If you don't like the noinline I can always remove it,

Yes, please. It's easier to argue about __always_inline and constant
propagation than "this code is too scary big for my CPU so I better do
an expensive function call if the code is actually needed".

--
Cheers,

David