On Fri, 2025-03-14 at 05:05 +0800, Kemeng Shi wrote: > In swap_entry_put_locked(), we will set slot to SWAP_HAS_CACHE before > using swap_entry_range_free to do actual swap entry freeing. This > introduce an unnecessary intermediate state. > By using __swap_entry_free() in swap_entry_put_locked(), we can eliminate > the need to set slot to SWAP_HAS_CACHE. > This change would make the behavior of swap_entry_put_locked() more > consistent with other put() operations which will do actual free work > after put last reference. > > Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx> Reviewed-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> > --- > mm/swapfile.c | 28 ++++++++++++---------------- > 1 file changed, 12 insertions(+), 16 deletions(-) > > diff --git a/mm/swapfile.c b/mm/swapfile.c > index 7c886f9dd6f9..ba37b9bff586 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -1367,9 +1367,11 @@ static inline void __swap_entries_free(struct swap_info_struct *si, > } > > static unsigned char swap_entry_put_locked(struct swap_info_struct *si, > - unsigned long offset, > + struct swap_cluster_info *ci, > + swp_entry_t entry, > unsigned char usage) > { > + unsigned long offset = swp_offset(entry); > unsigned char count; > unsigned char has_cache; > > @@ -1398,10 +1400,9 @@ static unsigned char swap_entry_put_locked(struct swap_info_struct *si, > } > > usage = count | has_cache; > - if (usage) > - WRITE_ONCE(si->swap_map[offset], usage); > - else > - WRITE_ONCE(si->swap_map[offset], SWAP_HAS_CACHE); > + WRITE_ONCE(si->swap_map[offset], usage); > + if (!usage) > + __swap_entries_free(si, ci, entry, 1); > > return usage; > } > @@ -1480,9 +1481,7 @@ static unsigned char swap_entry_put(struct swap_info_struct *si, > unsigned char usage; > > ci = lock_cluster(si, offset); > - usage = swap_entry_put_locked(si, offset, 1); > - if (!usage) > - swap_entry_range_free(si, ci, swp_entry(si->type, offset), 1); > + usage = swap_entry_put_locked(si, ci, entry, 1); > unlock_cluster(ci); > > return usage; > @@ -1562,8 +1561,8 @@ static void cluster_swap_free_nr(struct swap_info_struct *si, > > ci = lock_cluster(si, offset); > do { > - if (!swap_entry_put_locked(si, offset, usage)) > - swap_entry_range_free(si, ci, swp_entry(si->type, offset), 1); > + swap_entry_put_locked(si, ci, swp_entry(si->type, offset), > + usage); > } while (++offset < end); > unlock_cluster(ci); > } > @@ -1607,12 +1606,9 @@ void put_swap_folio(struct folio *folio, swp_entry_t entry) > ci = lock_cluster(si, offset); > if (swap_only_has_cache(si, offset, size)) > swap_entry_range_free(si, ci, entry, size); > - else { > - for (int i = 0; i < size; i++, entry.val++) { > - if (!swap_entry_put_locked(si, offset + i, SWAP_HAS_CACHE)) > - swap_entry_range_free(si, ci, entry, 1); > - } > - } > + else > + for (int i = 0; i < size; i++, entry.val++) > + swap_entry_put_locked(si, ci, entry, SWAP_HAS_CACHE); > unlock_cluster(ci); > } >