Re: [PATCH -V3 3/5] swap: remove __swp_swapcount()

Chris Li
2023-06-02T06:07:17Z

On Mon, May 29, 2023 at 02:13:53PM +0800, Huang Ying wrote:
> __swp_swapcount() just encloses the calling to swap_swapcount() with
> get/put_swap_device(). It is called in __read_swap_cache_async()
> only, which encloses the calling with get/put_swap_device() already.
> So, __read_swap_cache_async() can call swap_swapcount() directly.
>
> Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Hugh Dickins <hughd@google.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Tim Chen <tim.c.chen@linux.intel.com>
> Cc: Yang Shi <shy828301@gmail.com>
> Cc: Yu Zhao <yuzhao@google.com>
> Cc: Chris Li <chrisl@kernel.org>
> Cc: Yosry Ahmed <yosryahmed@google.com>
> ---
> include/linux/swap.h | 4 ++--
> mm/swap_state.c | 2 +-
> mm/swapfile.c | 20 +-------------------
> 3 files changed, 4 insertions(+), 22 deletions(-)
>
> diff --git a/include/linux/swap.h b/include/linux/swap.h
> index 3c69cb653cb9..f6bd51aa05ea 100644
> --- a/include/linux/swap.h
> +++ b/include/linux/swap.h
> @@ -512,7 +512,7 @@ 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 __swp_swapcount(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 *);
> extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
> @@ -590,7 +590,7 @@ static inline int __swap_count(swp_entry_t entry)
> return 0;
> }
>
> -static inline int __swp_swapcount(swp_entry_t entry)
> +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 a8450b4a110c..ef32353c18a6 100644
> --- a/mm/swap_state.c
> +++ b/mm/swap_state.c
> @@ -447,7 +447,7 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
> * as SWAP_HAS_CACHE. That's done in later part of code or
> * else swap_off will be aborted if we return NULL.
> */
> - if (!__swp_swapcount(entry) && swap_slot_cache_enabled)
> + if (!swap_swapcount(si, entry) && swap_slot_cache_enabled)
> goto fail_put_swap;
>
> /*
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index 8419cba9c192..e9cce775fb25 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -1443,7 +1443,7 @@ int __swap_count(swp_entry_t entry)
> * This does not give an exact answer when swap count is continued,
> * but does include the high COUNT_CONTINUED flag to allow for that.
> */
> -static int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry)
> +int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry)
> {
> pgoff_t offset = swp_offset(entry);
> struct swap_cluster_info *ci;
> @@ -1455,24 +1455,6 @@ static int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry)
> return count;
> }
>
> -/*
> - * How many references to @entry are currently swapped out?
> - * This does not give an exact answer when swap count is continued,
> - * but does include the high COUNT_CONTINUED flag to allow for that.
> - */
> -int __swp_swapcount(swp_entry_t entry)
> -{
> - int count = 0;
> - struct swap_info_struct *si;
> -
> - si = get_swap_device(entry);
> - if (si) {
> - count = swap_swapcount(si, entry);
> - put_swap_device(si);
> - }
> - return count;
> -}
> -
> /*
> * How many references to @entry are currently swapped out?
> * This considers COUNT_CONTINUED so it returns exact answer.
> --
> 2.39.2
>

Reviewed-by: Chris Li (Google) <chrisl@kernel.org>

Chris