Replace PFNs with addresses in readahead window calculation. This
simplified the logic and reduce the code line number.
No functionality change is expected.
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Kairui Song <kasong@xxxxxxxxxxx>
Cc: Barry Song <v-songbaohua@xxxxxxxx>
Cc: Chris Li <chrisl@xxxxxxxxxx>
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
---
mm/swap_state.c | 66 +++++++++++++++++++------------------------------
1 file changed, 25 insertions(+), 41 deletions(-)
diff --git a/mm/swap_state.c b/mm/swap_state.c
index e1dac70198a6..d2adbd7b571b 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -740,54 +740,40 @@ 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;
}
@@ -815,22 +801,20 @@ 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)
@@ -850,7 +834,7 @@ 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);
}
--
2.39.2
