Kairui Song <ryncsn@xxxxxxxxx> writes:
> From: Kairui Song <kasong@xxxxxxxxxxx>
>
> There is only one caller in swap subsystem now, where it can be inline
> smoothly, avoid the memory access and function call overheads.
>
> Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
> ---
> include/linux/swap.h | 6 ------
> mm/swap_state.c | 6 +++---
> mm/swapfile.c | 8 --------
> 3 files changed, 3 insertions(+), 17 deletions(-)
>
> diff --git a/include/linux/swap.h b/include/linux/swap.h
> index 2401990d954d..64a37819a9b3 100644
> --- a/include/linux/swap.h
> +++ b/include/linux/swap.h
> @@ -485,7 +485,6 @@ int swap_type_of(dev_t device, sector_t offset);
> int find_first_swap(dev_t *device);
> extern unsigned int count_swap_pages(int, int);
> extern sector_t swapdev_block(int, pgoff_t);
> -extern int __swap_count(swp_entry_t entry);
> extern int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry);
> extern int swp_swapcount(swp_entry_t entry);
> extern struct swap_info_struct *page_swap_info(struct page *);
> @@ -559,11 +558,6 @@ static inline void put_swap_folio(struct folio *folio, swp_entry_t swp)
> {
> }
>
> -static inline int __swap_count(swp_entry_t entry)
> -{
> - return 0;
> -}
> -
> static inline int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry)
> {
> return 0;
> diff --git a/mm/swap_state.c b/mm/swap_state.c
> index fb78f7f18ed7..d87c20f9f7ec 100644
> --- a/mm/swap_state.c
> +++ b/mm/swap_state.c
> @@ -316,9 +316,9 @@ void free_pages_and_swap_cache(struct encoded_page **pages, int nr)
> release_pages(pages, nr);
> }
>
> -static inline bool swap_use_no_readahead(struct swap_info_struct *si, swp_entry_t entry)
> +static inline bool swap_use_no_readahead(struct swap_info_struct *si, pgoff_t offset)
> {
> - return data_race(si->flags & SWP_SYNCHRONOUS_IO) && __swap_count(entry) == 1;
> + return data_race(si->flags & SWP_SYNCHRONOUS_IO) && swap_count(si->swap_map[offset]) == 1;
> }
>
> static inline bool swap_use_vma_readahead(struct swap_info_struct *si)
> @@ -928,7 +928,7 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
>
> si = swp_swap_info(entry);
> mpol = get_vma_policy(vmf->vma, vmf->address, 0, &ilx);
> - if (swap_use_no_readahead(si, entry)) {
> + if (swap_use_no_readahead(si, swp_offset(entry))) {
> page = swapin_no_readahead(entry, gfp_mask, mpol, ilx, vmf->vma->vm_mm);
> cached = false;
> } else if (swap_use_vma_readahead(si)) {
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index a8ae472ed2b6..e15a6c464a38 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -1431,14 +1431,6 @@ void swapcache_free_entries(swp_entry_t *entries, int n)
> spin_unlock(&p->lock);
> }
>
> -int __swap_count(swp_entry_t entry)
> -{
> - struct swap_info_struct *si = swp_swap_info(entry);
> - pgoff_t offset = swp_offset(entry);
> -
> - return swap_count(si->swap_map[offset]);
> -}
> -
I'd rather keep __swap_count() in the original place together with other
swap count related functions. And si->swap_map[] was hided in
swapfile.c before. I don't think the change will have any real
performance improvement.
> /*
> * How many references to @entry are currently swapped out?
> * This does not give an exact answer when swap count is continued,
--
Best Regards,
Huang, Ying
