Re: [PATCH 3/3] mm: zswap: make same_filled functions folio-friendly
From: Chengming Zhou
Date: Mon Jun 03 2024 - 02:08:03 EST
On 2024/5/24 11:38, Yosry Ahmed wrote:
> A variable name 'page' is used in zswap_is_folio_same_filled() and
> zswap_fill_page() to point at the kmapped data in a folio. Use 'data'
> instead to avoid confusion and stop it from showing up when searching
> for 'page' references in mm/zswap.c.
>
> While we are at it, move the kmap/kunmap calls into zswap_fill_page(),
> make it take in a folio, and rename it to zswap_fill_folio().
>
> Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
LGTM, thanks!
Reviewed-by: Chengming Zhou <chengming.zhou@xxxxxxxxx>
> ---
> mm/zswap.c | 30 +++++++++++++-----------------
> 1 file changed, 13 insertions(+), 17 deletions(-)
>
> diff --git a/mm/zswap.c b/mm/zswap.c
> index bac66991fb14e..b9b35ef86d9be 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -1375,35 +1375,35 @@ static void shrink_worker(struct work_struct *w)
> **********************************/
> static bool zswap_is_folio_same_filled(struct folio *folio, unsigned long *value)
> {
> - unsigned long *page;
> + unsigned long *data;
> unsigned long val;
> - unsigned int pos, last_pos = PAGE_SIZE / sizeof(*page) - 1;
> + unsigned int pos, last_pos = PAGE_SIZE / sizeof(*data) - 1;
> bool ret = false;
>
> - page = kmap_local_folio(folio, 0);
> - val = page[0];
> + data = kmap_local_folio(folio, 0);
> + val = data[0];
>
> - if (val != page[last_pos])
> + if (val != data[last_pos])
> goto out;
>
> for (pos = 1; pos < last_pos; pos++) {
> - if (val != page[pos])
> + if (val != data[pos])
> goto out;
> }
>
> *value = val;
> ret = true;
> out:
> - kunmap_local(page);
> + kunmap_local(data);
> return ret;
> }
>
> -static void zswap_fill_page(void *ptr, unsigned long value)
> +static void zswap_fill_folio(struct folio *folio, unsigned long value)
> {
> - unsigned long *page;
> + unsigned long *data = kmap_local_folio(folio, 0);
>
> - page = (unsigned long *)ptr;
> - memset_l(page, value, PAGE_SIZE / sizeof(unsigned long));
> + memset_l(data, value, PAGE_SIZE / sizeof(unsigned long));
> + kunmap_local(data);
> }
>
> /*********************************
> @@ -1554,7 +1554,6 @@ bool zswap_load(struct folio *folio)
> bool swapcache = folio_test_swapcache(folio);
> struct xarray *tree = swap_zswap_tree(swp);
> struct zswap_entry *entry;
> - u8 *dst;
>
> VM_WARN_ON_ONCE(!folio_test_locked(folio));
>
> @@ -1580,11 +1579,8 @@ bool zswap_load(struct folio *folio)
>
> if (entry->length)
> zswap_decompress(entry, folio);
> - else {
> - dst = kmap_local_folio(folio, 0);
> - zswap_fill_page(dst, entry->value);
> - kunmap_local(dst);
> - }
> + else
> + zswap_fill_folio(folio, entry->value);
>
> count_vm_event(ZSWPIN);
> if (entry->objcg)