David Hildenbrand <david@xxxxxxxxxx> writes:
> On 22.05.23 09:09, 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.
>
> The previous patch contained the hunk
>
> - if (!__swp_swapcount(entry) && swap_slot_cache_enabled)
> - return NULL;
> + if (!swap_swapcount(si, entry) && swap_slot_cache_enabled)
> + goto fail;
>
> So something is a bit off here. Either that hunk should go here, or
> this patch description has to be adjusted.
>
>
> But I guess patch #2 doesn't compile on its own because this patch
> here adds swap_swapcount() to include/linux/swap.h ?
Good catch! Will change this in the next version.
Best Regards,
Huang, Ying
>> Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
>> Cc: David Hildenbrand <david@xxxxxxxxxx>
>> Cc: Hugh Dickins <hughd@xxxxxxxxxx>
>> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
>> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
>> Cc: Michal Hocko <mhocko@xxxxxxxx>
>> Cc: Minchan Kim <minchan@xxxxxxxxxx>
>> Cc: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
>> Cc: Yang Shi <shy828301@xxxxxxxxx>
>> Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
>> ---
>> include/linux/swap.h | 4 ++--
>> mm/swapfile.c | 20 +-------------------
>> 2 files changed, 3 insertions(+), 21 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/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.
