Kairui Song <ryncsn@xxxxxxxxx> writes:
> From: Kairui Song <kasong@xxxxxxxxxxx>
>
> No feature change, simply move the routine to a standalone function to
> be re-used later. The error path handling is copied from the "out_page"
> label, to make the code change minimized for easier reviewing.
The error processing for mem_cgroup_swapin_charge_folio() failure is
changed a little. That looks OK for me. But you need to make it
explicit in change log. Especially, it's not "no feature change"
strictly.
--
Best Regards,
Huang, Ying
> Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
> ---
> mm/memory.c | 32 ++++----------------------------
> mm/swap.h | 8 ++++++++
> mm/swap_state.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 59 insertions(+), 28 deletions(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 7e1f4849463a..81dc9d467f4e 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3803,7 +3803,6 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
> swp_entry_t entry;
> pte_t pte;
> vm_fault_t ret = 0;
> - void *shadow = NULL;
>
> if (!pte_unmap_same(vmf))
> goto out;
> @@ -3867,33 +3866,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
> if (!folio) {
> if (data_race(si->flags & SWP_SYNCHRONOUS_IO) &&
> __swap_count(entry) == 1) {
> - /* skip swapcache */
> - folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0,
> - vma, vmf->address, false);
> - page = &folio->page;
> - if (folio) {
> - __folio_set_locked(folio);
> - __folio_set_swapbacked(folio);
> -
> - if (mem_cgroup_swapin_charge_folio(folio,
> - vma->vm_mm, GFP_KERNEL,
> - entry)) {
> - ret = VM_FAULT_OOM;
> - goto out_page;
> - }
> - mem_cgroup_swapin_uncharge_swap(entry);
> -
> - shadow = get_shadow_from_swap_cache(entry);
> - if (shadow)
> - workingset_refault(folio, shadow);
> -
> - folio_add_lru(folio);
> -
> - /* To provide entry to swap_read_folio() */
> - folio->swap = entry;
> - swap_read_folio(folio, true, NULL);
> - folio->private = NULL;
> - }
> + /* skip swapcache and readahead */
> + folio = swapin_direct(entry, GFP_HIGHUSER_MOVABLE, vmf);
> + if (folio)
> + page = &folio->page;
> } else {
> page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE,
> vmf);
> diff --git a/mm/swap.h b/mm/swap.h
> index 758c46ca671e..83eab7b67e77 100644
> --- a/mm/swap.h
> +++ b/mm/swap.h
> @@ -56,6 +56,8 @@ struct folio *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
> struct mempolicy *mpol, pgoff_t ilx);
> struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
> struct vm_fault *vmf);
> +struct folio *swapin_direct(swp_entry_t entry, gfp_t flag,
> + struct vm_fault *vmf);
>
> static inline unsigned int folio_swap_flags(struct folio *folio)
> {
> @@ -86,6 +88,12 @@ static inline struct folio *swap_cluster_readahead(swp_entry_t entry,
> return NULL;
> }
>
> +struct folio *swapin_direct(swp_entry_t entry, gfp_t flag,
> + struct vm_fault *vmf)
> +{
> + return NULL;
> +}
> +
> static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
> struct vm_fault *vmf)
> {
> diff --git a/mm/swap_state.c b/mm/swap_state.c
> index e671266ad772..645f5bcad123 100644
> --- a/mm/swap_state.c
> +++ b/mm/swap_state.c
> @@ -861,6 +861,53 @@ static struct folio *swap_vma_readahead(swp_entry_t targ_entry, gfp_t gfp_mask,
> return folio;
> }
>
> +/**
> + * swapin_direct - swap in a folio skipping swap cache and readahead
> + * @entry: swap entry of this memory
> + * @gfp_mask: memory allocation flags
> + * @vmf: fault information
> + *
> + * Returns the struct folio for entry and addr after the swap entry is read
> + * in.
> + */
> +struct folio *swapin_direct(swp_entry_t entry, gfp_t gfp_mask,
> + struct vm_fault *vmf)
> +{
> + struct vm_area_struct *vma = vmf->vma;
> + struct folio *folio;
> + void *shadow = NULL;
> +
> + /* skip swapcache */
> + folio = vma_alloc_folio(gfp_mask, 0,
> + vma, vmf->address, false);
> + if (folio) {
> + __folio_set_locked(folio);
> + __folio_set_swapbacked(folio);
> +
> + if (mem_cgroup_swapin_charge_folio(folio,
> + vma->vm_mm, GFP_KERNEL,
> + entry)) {
> + folio_unlock(folio);
> + folio_put(folio);
> + return NULL;
> + }
> + mem_cgroup_swapin_uncharge_swap(entry);
> +
> + shadow = get_shadow_from_swap_cache(entry);
> + if (shadow)
> + workingset_refault(folio, shadow);
> +
> + folio_add_lru(folio);
> +
> + /* To provide entry to swap_read_folio() */
> + folio->swap = entry;
> + swap_read_folio(folio, true, NULL);
> + folio->private = NULL;
> + }
> +
> + return folio;
> +}
> +
> /**
> * swapin_readahead - swap in pages in hope we need them soon
> * @entry: swap entry of this memory
