On 08/05/2024 09:30, Barry Song wrote: > On Wed, May 8, 2024 at 7:58 PM Huang, Ying <ying.huang@xxxxxxxxx> wrote: >> >> Ryan Roberts <ryan.roberts@xxxxxxx> writes: >> >>> On 03/05/2024 01:50, Barry Song wrote: >>>> From: Barry Song <v-songbaohua@xxxxxxxx> >>>> >>>> To streamline maintenance efforts, we propose discontinuing the use of >>>> swap_free(). Instead, we can simply invoke swap_free_nr() with nr set >>>> to 1. This adjustment offers the advantage of enabling batch processing >>>> within kernel/power/swap.c. Furthermore, swap_free_nr() is designed with >>>> a bitmap consisting of only one long, resulting in overhead that can be >>>> ignored for cases where nr equals 1. >>>> >>>> Suggested-by: "Huang, Ying" <ying.huang@xxxxxxxxx> >>>> Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx> >>>> Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> >>>> Cc: Pavel Machek <pavel@xxxxxx> >>>> Cc: Len Brown <len.brown@xxxxxxxxx> >>>> Cc: Hugh Dickins <hughd@xxxxxxxxxx> >>>> --- >>>> include/linux/swap.h | 5 ----- >>>> kernel/power/swap.c | 7 +++---- >>>> mm/memory.c | 2 +- >>>> mm/rmap.c | 4 ++-- >>>> mm/shmem.c | 4 ++-- >>>> mm/swapfile.c | 19 +++++-------------- >>>> 6 files changed, 13 insertions(+), 28 deletions(-) >>>> >>>> diff --git a/include/linux/swap.h b/include/linux/swap.h >>>> index d1d35e92d7e9..f03cb446124e 100644 >>>> --- a/include/linux/swap.h >>>> +++ b/include/linux/swap.h >>>> @@ -482,7 +482,6 @@ extern int add_swap_count_continuation(swp_entry_t, gfp_t); >>>> extern void swap_shmem_alloc(swp_entry_t); >>>> extern int swap_duplicate(swp_entry_t); >>>> extern int swapcache_prepare(swp_entry_t); >>>> -extern void swap_free(swp_entry_t); >>> >>> I wonder if it would be cleaner to: >>> >>> #define swap_free(entry) swap_free_nr((entry), 1) >>> >>> To save all the churn for the callsites that just want to pass a single entry? >> >> I prefer this way. Although I prefer inline functions. Yes, I agree inline function is the better approach. > > Yes, using static inline is preferable. I've recently submitted > a checkpatch/codestyle for this, which can be found at: > https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/commit/?h=mm-everything&id=39c58d5ed036 > https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/commit/?h=mm-everything&id=8379bf0b0e1f5 > > Using static inline aligns with the established rule. > >> >> Otherwise, LGTM. Feel free to add >> >> Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx> > > Thanks! > >> >> in the future version. > > I believe Christoph's vote leans towards simply removing swap_free_nr > and renaming it to swap_free, while adding a new parameter as follows. > > void swap_free(swp_entry_t entry, int nr); > { > } > > now I see Ryan and you prefer > > static inline swap_free() > { > swap_free_nr(...., 1) > } > > Chris slightly favors discouraging the use of swap_free() without the > new parameter. Removing swap_free() can address this concern. > > It seems that maintaining swap_free() and having it call swap_free_nr() with > a default value of 1 received the most support. > > To align with free_swap_and_cache() and free_swap_and_cache_nr(), > I'll proceed with the "static inline" approach in the new version. Please > voice any objections you may have, Christoph, Chris. I'm happy with either route. If you end up adding a nr param to swap_free() then it would also be good to give free_swap_and_cache_nr() the same treatment. > >> >>>> extern void swap_free_nr(swp_entry_t entry, int nr_pages); >>>> extern void swapcache_free_entries(swp_entry_t *entries, int n); >>>> extern void free_swap_and_cache_nr(swp_entry_t entry, int nr); >>>> @@ -561,10 +560,6 @@ static inline int swapcache_prepare(swp_entry_t swp) >>>> return 0; >>>> } >>>> >>>> -static inline void swap_free(swp_entry_t swp) >>>> -{ >>>> -} >>>> - >>>> static inline void swap_free_nr(swp_entry_t entry, int nr_pages) >>>> { >>>> } >>>> diff --git a/kernel/power/swap.c b/kernel/power/swap.c >>>> index 5bc04bfe2db1..6befaa88a342 100644 >>>> --- a/kernel/power/swap.c >>>> +++ b/kernel/power/swap.c >>>> @@ -181,7 +181,7 @@ sector_t alloc_swapdev_block(int swap) >>>> offset = swp_offset(get_swap_page_of_type(swap)); >>>> if (offset) { >>>> if (swsusp_extents_insert(offset)) >>>> - swap_free(swp_entry(swap, offset)); >>>> + swap_free_nr(swp_entry(swap, offset), 1); >>>> else >>>> return swapdev_block(swap, offset); >>>> } >>>> @@ -200,12 +200,11 @@ void free_all_swap_pages(int swap) >>>> >>>> while ((node = swsusp_extents.rb_node)) { >>>> struct swsusp_extent *ext; >>>> - unsigned long offset; >>>> >>>> ext = rb_entry(node, struct swsusp_extent, node); >>>> rb_erase(node, &swsusp_extents); >>>> - for (offset = ext->start; offset <= ext->end; offset++) >>>> - swap_free(swp_entry(swap, offset)); >>>> + swap_free_nr(swp_entry(swap, ext->start), >>>> + ext->end - ext->start + 1); >>>> >>>> kfree(ext); >>>> } >>>> diff --git a/mm/memory.c b/mm/memory.c >>>> index eea6e4984eae..f033eb3528ba 100644 >>>> --- a/mm/memory.c >>>> +++ b/mm/memory.c >>>> @@ -4225,7 +4225,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) >>>> * We're already holding a reference on the page but haven't mapped it >>>> * yet. >>>> */ >>>> - swap_free(entry); >>>> + swap_free_nr(entry, 1); >>>> if (should_try_to_free_swap(folio, vma, vmf->flags)) >>>> folio_free_swap(folio); >>>> >>>> diff --git a/mm/rmap.c b/mm/rmap.c >>>> index 087a79f1f611..39ec7742acec 100644 >>>> --- a/mm/rmap.c >>>> +++ b/mm/rmap.c >>>> @@ -1865,7 +1865,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, >>>> goto walk_done_err; >>>> } >>>> if (arch_unmap_one(mm, vma, address, pteval) < 0) { >>>> - swap_free(entry); >>>> + swap_free_nr(entry, 1); >>>> set_pte_at(mm, address, pvmw.pte, pteval); >>>> goto walk_done_err; >>>> } >>>> @@ -1873,7 +1873,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, >>>> /* See folio_try_share_anon_rmap(): clear PTE first. */ >>>> if (anon_exclusive && >>>> folio_try_share_anon_rmap_pte(folio, subpage)) { >>>> - swap_free(entry); >>>> + swap_free_nr(entry, 1); >>>> set_pte_at(mm, address, pvmw.pte, pteval); >>>> goto walk_done_err; >>>> } >>>> diff --git a/mm/shmem.c b/mm/shmem.c >>>> index fa2a0ed97507..bfc8a2beb24f 100644 >>>> --- a/mm/shmem.c >>>> +++ b/mm/shmem.c >>>> @@ -1836,7 +1836,7 @@ static void shmem_set_folio_swapin_error(struct inode *inode, pgoff_t index, >>>> * in shmem_evict_inode(). >>>> */ >>>> shmem_recalc_inode(inode, -1, -1); >>>> - swap_free(swap); >>>> + swap_free_nr(swap, 1); >>>> } >>>> >>>> /* >>>> @@ -1927,7 +1927,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, >>>> >>>> delete_from_swap_cache(folio); >>>> folio_mark_dirty(folio); >>>> - swap_free(swap); >>>> + swap_free_nr(swap, 1); >>>> put_swap_device(si); >>>> >>>> *foliop = folio; >>>> diff --git a/mm/swapfile.c b/mm/swapfile.c >>>> index ec12f2b9d229..ddcd0f24b9a1 100644 >>>> --- a/mm/swapfile.c >>>> +++ b/mm/swapfile.c >>>> @@ -1343,19 +1343,6 @@ static void swap_entry_free(struct swap_info_struct *p, swp_entry_t entry) >>>> swap_range_free(p, offset, 1); >>>> } >>>> >>>> -/* >>>> - * Caller has made sure that the swap device corresponding to entry >>>> - * is still around or has not been recycled. >>>> - */ >>>> -void swap_free(swp_entry_t entry) >>>> -{ >>>> - struct swap_info_struct *p; >>>> - >>>> - p = _swap_info_get(entry); >>>> - if (p) >>>> - __swap_entry_free(p, entry); >>>> -} >>>> - >>>> static void cluster_swap_free_nr(struct swap_info_struct *sis, >>>> unsigned long offset, int nr_pages) >>>> { >>>> @@ -1385,6 +1372,10 @@ static void cluster_swap_free_nr(struct swap_info_struct *sis, >>>> unlock_cluster_or_swap_info(sis, ci); >>>> } >>>> >>>> +/* >>>> + * Caller has made sure that the swap device corresponding to entry >>>> + * is still around or has not been recycled. >>>> + */ >>>> void swap_free_nr(swp_entry_t entry, int nr_pages) >>>> { >>>> int nr; >>>> @@ -1930,7 +1921,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, >>>> new_pte = pte_mkuffd_wp(new_pte); >>>> setpte: >>>> set_pte_at(vma->vm_mm, addr, pte, new_pte); >>>> - swap_free(entry); >>>> + swap_free_nr(entry, 1); >>>> out: >>>> if (pte) >>>> pte_unmap_unlock(pte, ptl); >> >> -- >> Best Regards, >> Huang, Ying > > Thanks > Barry
