Messages in this thread | | | Date | Mon, 17 May 2021 22:17:32 -0400 | From | Peter Xu <> | Subject | Re: [PATCH v8 1/8] mm: Remove special swap entry functions |
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On Wed, Apr 07, 2021 at 06:42:31PM +1000, Alistair Popple wrote: > +static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry) > +{ > + struct page *p = pfn_to_page(swp_offset(entry)); > + > + /* > + * Any use of migration entries may only occur while the > + * corresponding page is locked > + */ > + BUG_ON(is_migration_entry(entry) && !PageLocked(p)); > + > + return p; > +}
Would swap_pfn_entry_to_page() be slightly better?
The thing is it's very easy to read pfn_*() as a function to take a pfn as parameter...
Since I'm also recently working on some swap-related new ptes [1], I'm thinking whether we could name these swap entries as "swap XXX entries". Say, "swap hwpoison entry", "swap pfn entry" (which is a superset of "swap migration entry", "swap device exclusive entry", ...). That's where I came with the above swap_pfn_entry_to_page(), then below will be naturally is_swap_pfn_entry().
No strong opinion as this is already a v8 series (and sorry to chim in this late), just to raise this up.
[1] https://lore.kernel.org/lkml/20210427161317.50682-1-peterx@redhat.com/
Thanks,
> + > +/* > + * A pfn swap entry is a special type of swap entry that always has a pfn stored > + * in the swap offset. They are used to represent unaddressable device memory > + * and to restrict access to a page undergoing migration. > + */ > +static inline bool is_pfn_swap_entry(swp_entry_t entry) > +{ > + return is_migration_entry(entry) || is_device_private_entry(entry); > +}
-- Peter Xu
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