On Sun, Nov 19, 2023 at 11:48 AM Kairui Song <ryncsn@xxxxxxxxx> wrote:
>
> From: Kairui Song <kasong@xxxxxxxxxxx>
>
> No feature change, simply move the routine to a standalone function to
> be used later. The error path handling is copied from the "out_page"
> label, to make the code change minimized for easier reviewing.
>
> Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
> ---
> mm/memory.c | 33 +++++----------------------------
> mm/swap.h | 2 ++
> mm/swap_state.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 55 insertions(+), 28 deletions(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 70ffa867b1be..fba4a5229163 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3794,7 +3794,6 @@ 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;
> @@ -3858,33 +3857,11 @@ 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);
> - 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);
> - page = &folio->page;
> -
> - /* To provide entry to swap_readpage() */
> - folio->swap = entry;
> - swap_readpage(page, true, NULL);
> - folio->private = NULL;
> - }
> + /* skip swapcache and readahead */
> + page = swapin_no_readahead(entry, GFP_HIGHUSER_MOVABLE,
> + vmf);
A minor point, swapin_no_readahead() is expressed in negative words.
Better use positive words to express what the function does rather
than what the function does not do.
I am terrible at naming functions myself. I can think of something
along the lines of:
swapin_direct (no cache).
swapin_minimal?
swapin_entry_only?
Please suggest better names for basic, bare minimum.
Chris
