On Wed, Mar 27, 2024 at 02:05:36PM +0100, David Hildenbrand wrote:
> Let's consistently call the "fast-only" part of GUP "GUP-fast" and rename
> all relevant internal functions to start with "gup_fast", to make it
> clearer that this is not ordinary GUP. The current mixture of
> "lockless", "gup" and "gup_fast" is confusing.
>
> Further, avoid the term "huge" when talking about a "leaf" -- for
> example, we nowadays check pmd_leaf() because pmd_huge() is gone. For the
> "hugepd"/"hugepte" stuff, it's part of the name ("is_hugepd"), so that
> says.
>
> What remains is the "external" interface:
> * get_user_pages_fast_only()
> * get_user_pages_fast()
> * pin_user_pages_fast()
>
> And the "internal" interface that handles GUP-fast + fallback:
> * internal_get_user_pages_fast()
This would like a better name too. How about gup_fast_fallback() ?
> The high-level internal function for GUP-fast is now:
> * gup_fast()
>
> The basic GUP-fast walker functions:
> * gup_pgd_range() -> gup_fast_pgd_range()
> * gup_p4d_range() -> gup_fast_p4d_range()
> * gup_pud_range() -> gup_fast_pud_range()
> * gup_pmd_range() -> gup_fast_pmd_range()
> * gup_pte_range() -> gup_fast_pte_range()
> * gup_huge_pgd() -> gup_fast_pgd_leaf()
> * gup_huge_pud() -> gup_fast_pud_leaf()
> * gup_huge_pmd() -> gup_fast_pmd_leaf()
>
> The weird hugepd stuff:
> * gup_huge_pd() -> gup_fast_hugepd()
> * gup_hugepte() -> gup_fast_hugepte()
>
> The weird devmap stuff:
> * __gup_device_huge_pud() -> gup_fast_devmap_pud_leaf()
> * __gup_device_huge_pmd -> gup_fast_devmap_pmd_leaf()
> * __gup_device_huge() -> gup_fast_devmap_leaf()
>
> Helper functions:
> * unpin_user_pages_lockless() -> gup_fast_unpin_user_pages()
> * gup_fast_folio_allowed() is already properly named
> * gup_fast_permitted() is already properly named
>
> With "gup_fast()", we now even have a function that is referred to in
> comment in mm/mmu_gather.c.
>
> Signed-off-by: David Hildenbrand <[email protected]>
> ---
> mm/gup.c | 164 ++++++++++++++++++++++++++++---------------------------
> 1 file changed, 84 insertions(+), 80 deletions(-)
I think it is a great idea, it always takes a moment to figure out if
a function is part of the fast callchain or not..
(even better would be to shift the fast stuff into its own file, but I
expect that is too much)
Reviewed-by: Jason Gunthorpe <[email protected]>
Jason
On 27.03.24 14:52, Jason Gunthorpe wrote:
> On Wed, Mar 27, 2024 at 02:05:36PM +0100, David Hildenbrand wrote:
>> Let's consistently call the "fast-only" part of GUP "GUP-fast" and rename
>> all relevant internal functions to start with "gup_fast", to make it
>> clearer that this is not ordinary GUP. The current mixture of
>> "lockless", "gup" and "gup_fast" is confusing.
>>
>> Further, avoid the term "huge" when talking about a "leaf" -- for
>> example, we nowadays check pmd_leaf() because pmd_huge() is gone. For the
>> "hugepd"/"hugepte" stuff, it's part of the name ("is_hugepd"), so that
>> says.
>>
>> What remains is the "external" interface:
>> * get_user_pages_fast_only()
>> * get_user_pages_fast()
>> * pin_user_pages_fast()
>>
>> And the "internal" interface that handles GUP-fast + fallback:
>> * internal_get_user_pages_fast()
>
> This would like a better name too. How about gup_fast_fallback() ?
Yes, I was not able to come up with something I liked. But I do like
your proposal, so I'll do that!
[...]
>
> I think it is a great idea, it always takes a moment to figure out if
> a function is part of the fast callchain or not..
>
> (even better would be to shift the fast stuff into its own file, but I
> expect that is too much)
Yes, one step at a time :)
>
> Reviewed-by: Jason Gunthorpe <[email protected]>
Thanks Jason!
--
Cheers,
David / dhildenb