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mm,swap: simplify VMA based swap readahead window calculation

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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" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Huang Ying 2024-05-31 16:12:30 +08:00 committed by Andrew Morton
parent dce08dd2e8
commit ba518f4d4b
1 changed files with 25 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
mm/swap_state.c
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@ -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);
}