<minchan@xxxxxxxxxx> writes:
[snip]
> diff --git a/mm/swap_state.c b/mm/swap_state.c
> index 39ae7cfad90f..c56cce64b2c3 100644
> --- a/mm/swap_state.c
> +++ b/mm/swap_state.c
> @@ -332,32 +332,38 @@ struct page *lookup_swap_cache(swp_entry_t entry, struct vm_area_struct *vma,
> unsigned long addr)
> {
> struct page *page;
> - unsigned long ra_info;
> - int win, hits, readahead;
>
> page = find_get_page(swap_address_space(entry), swp_offset(entry));
>
> INC_CACHE_INFO(find_total);
> if (page) {
> + bool vma_ra = swap_use_vma_readahead();
> + bool readahead = TestClearPageReadahead(page);
> +
TestClearPageReadahead() cannot be called for compound page. As in
PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND)
TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND)
> INC_CACHE_INFO(find_success);
> if (unlikely(PageTransCompound(page)))
> return page;
> - readahead = TestClearPageReadahead(page);
So we can only call it here after checking whether page is compound.
Best Regards,
Huang, Ying
> - if (vma) {
> - ra_info = GET_SWAP_RA_VAL(vma);
> - win = SWAP_RA_WIN(ra_info);
> - hits = SWAP_RA_HITS(ra_info);
> +
> + if (vma && vma_ra) {
> + unsigned long ra_val;
> + int win, hits;
> +
> + ra_val = GET_SWAP_RA_VAL(vma);
> + win = SWAP_RA_WIN(ra_val);
> + hits = SWAP_RA_HITS(ra_val);
> if (readahead)
> hits = min_t(int, hits + 1, SWAP_RA_HITS_MAX);
> atomic_long_set(&vma->swap_readahead_info,
> SWAP_RA_VAL(addr, win, hits));
> }
> +
> if (readahead) {
> count_vm_event(SWAP_RA_HIT);
> - if (!vma)
> + if (!vma || !vma_ra)
> atomic_inc(&swapin_readahead_hits);
> }
> }
> +
> return page;
> }
>
[snip]
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