Christoph Hellwig wrote:
> Split the block device case from swap_readpage into a separate helper,
> following the abstraction for file based swap and frontswap.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> mm/page_io.c | 68 +++++++++++++++++++++++++++-------------------------
> 1 file changed, 35 insertions(+), 33 deletions(-)
>
> diff --git a/mm/page_io.c b/mm/page_io.c
> index 6f7166fdc4b2bb..ce0b3638094f85 100644
> --- a/mm/page_io.c
> +++ b/mm/page_io.c
> @@ -445,44 +445,15 @@ static void swap_readpage_fs(struct page *page,
> *plug = sio;
> }
>
> -void swap_readpage(struct page *page, bool synchronous, struct swap_iocb **plug)
> +static void swap_readpage_bdev(struct page *page, bool synchronous,
> + struct swap_info_struct *sis)
> {
> struct bio *bio;
> - struct swap_info_struct *sis = page_swap_info(page);
> - bool workingset = PageWorkingset(page);
> - unsigned long pflags;
> - bool in_thrashing;
> -
> - VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page);
> - VM_BUG_ON_PAGE(!PageLocked(page), page);
> - VM_BUG_ON_PAGE(PageUptodate(page), page);
> -
> - /*
> - * Count submission time as memory stall and delay. When the device
> - * is congested, or the submitting cgroup IO-throttled, submission
> - * can be a significant part of overall IO time.
> - */
> - if (workingset) {
> - delayacct_thrashing_start(&in_thrashing);
> - psi_memstall_enter(&pflags);
> - }
> - delayacct_swapin_start();
> -
> - if (frontswap_load(page) == 0) {
> - SetPageUptodate(page);
> - unlock_page(page);
> - goto out;
> - }
> -
> - if (data_race(sis->flags & SWP_FS_OPS)) {
> - swap_readpage_fs(page, plug);
> - goto out;
> - }
>
> if ((sis->flags & SWP_SYNCHRONOUS_IO) &&
> !bdev_read_page(sis->bdev, swap_page_sector(page), page)) {
> count_vm_event(PSWPIN);
> - goto out;
> + return;
> }
>
> bio = bio_alloc(sis->bdev, 1, REQ_OP_READ, GFP_KERNEL);
> @@ -509,8 +480,39 @@ void swap_readpage(struct page *page, bool synchronous, struct swap_iocb **plug)
> }
> __set_current_state(TASK_RUNNING);
> bio_put(bio);
> +}
> +
> +void swap_readpage(struct page *page, bool synchronous, struct swap_iocb **plug)
> +{
> + struct swap_info_struct *sis = page_swap_info(page);
> + bool workingset = PageWorkingset(page);
> + unsigned long pflags;
> + bool in_thrashing;
> +
> + VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page);
> + VM_BUG_ON_PAGE(!PageLocked(page), page);
> + VM_BUG_ON_PAGE(PageUptodate(page), page);
> +
> + /*
> + * Count submission time as memory stall and delay. When the device
> + * is congested, or the submitting cgroup IO-throttled, submission
> + * can be a significant part of overall IO time.
> + */
> + if (workingset) {
> + delayacct_thrashing_start(&in_thrashing);
> + psi_memstall_enter(&pflags);
> + }
> + delayacct_swapin_start();
> +
> + if (frontswap_load(page) == 0) {
> + SetPageUptodate(page);
> + unlock_page(page);
> + } else if (data_race(sis->flags & SWP_FS_OPS)) {
> + swap_readpage_fs(page, plug);
> + } else {
> + swap_readpage_bdev(page, synchronous, sis);
> + }
>
> -out:
> if (workingset) {
> delayacct_thrashing_end(&in_thrashing);
> psi_memstall_leave(&pflags);
Looks good, passes tests,
Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
