From ba518f4d4b84c2c99fd03e77479e5c7f6767faf6 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Fri, 31 May 2024 16:12:30 +0800 Subject: mm,swap: simplify VMA based swap readahead window calculation Replace PFNs with addresses in readahead window calculation. This simplified the logic and reduce the code line number. No functionality change is expected. Link: https://lkml.kernel.org/r/20240531081230.310128-4-ying.huang@intel.com Signed-off-by: "Huang, Ying" Cc: Hugh Dickins Cc: Alistair Popple Cc: Anshuman Khandual Cc: David Hildenbrand Cc: Mel Gorman Cc: Miaohe Lin Cc: Minchan Kim Cc: Ryan Roberts Cc: Yang Shi Cc: Yu Zhao Cc: Kairui Song Cc: Barry Song Cc: Chris Li Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- mm/swap_state.c | 66 ++++++++++++++++++++++----------------------------------- 1 file changed, 25 insertions(+), 41 deletions(-) (limited to 'mm/swap_state.c') diff --git a/mm/swap_state.c b/mm/swap_state.c index eb7a306a2424..0803eedeabe3 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -741,54 +741,40 @@ void exit_swap_address_space(unsigned int type) swapper_spaces[type] = NULL; } -static unsigned short swap_vma_ra_win(struct vm_fault *vmf, - unsigned short *offset, - unsigned short *nr_pte) +static int swap_vma_ra_win(struct vm_fault *vmf, unsigned long *start, + unsigned long *end) { struct vm_area_struct *vma = vmf->vma; unsigned long ra_val; - unsigned long faddr, pfn, fpfn, lpfn, rpfn; - unsigned long start, end; + unsigned long faddr, prev_faddr, left, right; unsigned int max_win, hits, prev_win, win; - max_win = 1 << min_t(unsigned int, READ_ONCE(page_cluster), - SWAP_RA_ORDER_CEILING); + max_win = 1 << min(READ_ONCE(page_cluster), SWAP_RA_ORDER_CEILING); if (max_win == 1) return 1; faddr = vmf->address; - fpfn = PFN_DOWN(faddr); ra_val = GET_SWAP_RA_VAL(vma); - pfn = PFN_DOWN(SWAP_RA_ADDR(ra_val)); + prev_faddr = SWAP_RA_ADDR(ra_val); prev_win = SWAP_RA_WIN(ra_val); hits = SWAP_RA_HITS(ra_val); - win = __swapin_nr_pages(pfn, fpfn, hits, max_win, prev_win); - atomic_long_set(&vma->swap_readahead_info, - SWAP_RA_VAL(faddr, win, 0)); + win = __swapin_nr_pages(PFN_DOWN(prev_faddr), PFN_DOWN(faddr), hits, + max_win, prev_win); + atomic_long_set(&vma->swap_readahead_info, SWAP_RA_VAL(faddr, win, 0)); if (win == 1) return 1; - if (fpfn == pfn + 1) { - lpfn = fpfn; - rpfn = fpfn + win; - } else if (pfn == fpfn + 1) { - lpfn = fpfn - win + 1; - rpfn = fpfn + 1; - } else { - unsigned int left = (win - 1) / 2; - - lpfn = fpfn - left; - rpfn = fpfn + win - left; - } - if ((long)lpfn < 0) - lpfn = 0; - start = max3(lpfn, PFN_DOWN(vma->vm_start), - PFN_DOWN(faddr & PMD_MASK)); - end = min3(rpfn, PFN_DOWN(vma->vm_end), - PFN_DOWN((faddr & PMD_MASK) + PMD_SIZE)); - - *nr_pte = end - start; - *offset = fpfn - start; + if (faddr == prev_faddr + PAGE_SIZE) + left = faddr; + else if (prev_faddr == faddr + PAGE_SIZE) + left = faddr - (win << PAGE_SHIFT) + PAGE_SIZE; + else + left = faddr - (((win - 1) / 2) << PAGE_SHIFT); + right = left + (win << PAGE_SHIFT); + if ((long)left < 0) + left = 0; + *start = max3(left, vma->vm_start, faddr & PMD_MASK); + *end = min3(right, vma->vm_end, (faddr & PMD_MASK) + PMD_SIZE); return win; } @@ -816,22 +802,20 @@ static struct folio *swap_vma_readahead(swp_entry_t targ_entry, gfp_t gfp_mask, struct swap_iocb *splug = NULL; struct folio *folio; pte_t *pte = NULL, pentry; - unsigned long addr; + int win; + unsigned long start, end, addr; swp_entry_t entry; pgoff_t ilx; - unsigned int i; bool page_allocated; - unsigned short win, nr_pte, offset; - win = swap_vma_ra_win(vmf, &offset, &nr_pte); + win = swap_vma_ra_win(vmf, &start, &end); if (win == 1) goto skip; - addr = vmf->address - offset * PAGE_SIZE; - ilx = targ_ilx - offset; + ilx = targ_ilx - PFN_DOWN(vmf->address - start); blk_start_plug(&plug); - for (i = 0; i < nr_pte; i++, ilx++, addr += PAGE_SIZE) { + for (addr = start; addr < end; ilx++, addr += PAGE_SIZE) { if (!pte++) { pte = pte_offset_map(vmf->pmd, addr); if (!pte) @@ -851,7 +835,7 @@ static struct folio *swap_vma_readahead(swp_entry_t targ_entry, gfp_t gfp_mask, continue; if (page_allocated) { swap_read_folio(folio, false, &splug); - if (i != offset) { + if (addr != vmf->address) { folio_set_readahead(folio); count_vm_event(SWAP_RA); } -- cgit v1.2.3-58-ga151