On Fri, Nov 06, 2020 at 12:30:37PM +0000, Matthew Wilcox (Oracle) wrote:
> Declaring a pagevec continues to create a pagevec which is the same size,
> but functions which manipulate pagevecs no longer rely on this.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> include/linux/pagevec.h | 20 ++++++++++++++++----
> mm/swap.c | 8 ++++++++
> 2 files changed, 24 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h
> index 875a3f0d9dd2..ee5d3c4da8da 100644
> --- a/include/linux/pagevec.h
> +++ b/include/linux/pagevec.h
> @@ -18,9 +18,15 @@ struct page;
> struct address_space;
>
> struct pagevec {
> - unsigned char nr;
> - bool percpu_pvec_drained;
> - struct page *pages[PAGEVEC_SIZE];
> + union {
> + struct {
> + unsigned char sz;
> + unsigned char nr;
> + bool percpu_pvec_drained;
This should probably be removed, it's only used by the swap code and I don't
think it belongs in the generic data structure. That would mean nr and size (and
let's please use more standard naming...) can be u32, not u8s.
> + struct page *pages[PAGEVEC_SIZE];
> + };
> + void *__p[PAGEVEC_SIZE + 1];
What's up with this union?
> + };
> };
>
> void __pagevec_release(struct pagevec *pvec);
> @@ -41,6 +47,7 @@ static inline unsigned pagevec_lookup_tag(struct pagevec *pvec,
>
> static inline void pagevec_init(struct pagevec *pvec)
> {
> + pvec->sz = PAGEVEC_SIZE;
> pvec->nr = 0;
> pvec->percpu_pvec_drained = false;
> }
> @@ -50,6 +57,11 @@ static inline void pagevec_reinit(struct pagevec *pvec)
> pvec->nr = 0;
> }
>
> +static inline unsigned pagevec_size(struct pagevec *pvec)
> +{
> + return pvec->sz;
> +}
> +
> static inline unsigned pagevec_count(struct pagevec *pvec)
> {
> return pvec->nr;
> @@ -57,7 +69,7 @@ static inline unsigned pagevec_count(struct pagevec *pvec)
>
> static inline unsigned pagevec_space(struct pagevec *pvec)
> {
> - return PAGEVEC_SIZE - pvec->nr;
> + return pvec->sz - pvec->nr;
> }
>
> /*
> diff --git a/mm/swap.c b/mm/swap.c
> index 2ee3522a7170..d093fb30f038 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -52,6 +52,7 @@ struct lru_rotate {
> };
> static DEFINE_PER_CPU(struct lru_rotate, lru_rotate) = {
> .lock = INIT_LOCAL_LOCK(lock),
> + .pvec.sz = PAGEVEC_SIZE,
> };
>
> /*
> @@ -70,6 +71,13 @@ struct lru_pvecs {
> };
> static DEFINE_PER_CPU(struct lru_pvecs, lru_pvecs) = {
> .lock = INIT_LOCAL_LOCK(lock),
> + .lru_add.sz = PAGEVEC_SIZE,
> + .lru_deactivate_file.sz = PAGEVEC_SIZE,
> + .lru_deactivate.sz = PAGEVEC_SIZE,
> + .lru_lazyfree.sz = PAGEVEC_SIZE,
> +#ifdef CONFIG_SMP
> + .activate_page.sz = PAGEVEC_SIZE,
> +#endif
> };
>
> /*
> --
> 2.28.0
>
