Matthew Wilcox <willy@xxxxxxxxxxxxx> writes:
> On Mon, Mar 06, 2023 at 08:51:45PM +0530, Ritesh Harjani wrote:
>> Matthew Wilcox <willy@xxxxxxxxxxxxx> writes:
>>
>> > On Mon, Mar 06, 2023 at 12:21:48PM +0530, Ritesh Harjani wrote:
>> >> "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> writes:
>> >>
>> >> > All the callers now have a folio, so pass that in and operate on folios.
>> >> > Removes four calls to compound_head().
>> >>
>> >> Why do you say four? Isn't it 3 calls of PageUptodate(page) which
>> >> removes calls to compound_head()? Which one did I miss?
>> >>
>> >> > - BUG_ON(!PageLocked(page));
>> >> > + BUG_ON(!folio_test_locked(folio));
>> >
>> > That one ;-)
>>
>> __PAGEFLAG(Locked, locked, PF_NO_TAIL)
>>
>> #define __PAGEFLAG(uname, lname, policy) \
>> TESTPAGEFLAG(uname, lname, policy) \
>> __SETPAGEFLAG(uname, lname, policy) \
>> __CLEARPAGEFLAG(uname, lname, policy)
>>
>> #define TESTPAGEFLAG(uname, lname, policy) \
>> static __always_inline bool folio_test_##lname(struct folio *folio) \
>> { return test_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
>> static __always_inline int Page##uname(struct page *page) \
>> { return test_bit(PG_##lname, &policy(page, 0)->flags); }
>>
>> How? PageLocked(page) doesn't do any compount_head() calls no?
>
> You missed one piece of the definition ...
>
> #define PF_NO_TAIL(page, enforce) ({ \
> VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
> PF_POISONED_CHECK(compound_head(page)); })
aah yes, right. Thanks for pointing it.
-ritesh
