From c8be03806738c86521dbf1e0503bc90855fb99a3 Mon Sep 17 00:00:00 2001 From: Yin Fengwei Date: Thu, 14 Sep 2023 21:47:41 +0800 Subject: filemap: add filemap_map_order0_folio() to handle order0 folio Kernel test robot reported regressions for several benchmarks [1]. The regression are related with commit: de74976eb65151a2f568e477fc2e0032df5b22b4 ("filemap: add filemap_map_folio_range()") It turned out that function filemap_map_folio_range() brings these regressions when handle folio with order0. Add filemap_map_order0_folio() to handle order0 folio. The benefit come from two perspectives: - the code size is smaller (around 126 bytes) - no loop Testing showed the regressions reported by 0day [1] all are fixed: commit 9f1f5b60e76d44fa: parent commit of de74976eb65151a2 commit fbdf9263a3d7fdbd: latest mm-unstable commit commit 7fbfe2003f84686d: this fixing patch 9f1f5b60e76d44fa fbdf9263a3d7fdbd 7fbfe2003f84686d ---------------- --------------------------- --------------------------- 3843810 -21.4% 3020268 +4.6% 4018708 stress-ng.bad-altstack.ops 64061 -21.4% 50336 +4.6% 66977 stress-ng.bad-altstack.ops_per_sec 1709026 -14.4% 1462102 +2.4% 1750757 stress-ng.fork.ops 28483 -14.4% 24368 +2.4% 29179 stress-ng.fork.ops_per_sec 3685088 -53.6% 1710976 +0.5% 3702454 stress-ng.zombie.ops 56732 -65.3% 19667 +0.7% 57107 stress-ng.zombie.ops_per_sec 61874 -12.1% 54416 +0.4% 62136 vm-scalability.median 13527663 -11.7% 11942117 -0.1% 13513946 vm-scalability.throughput 4.066e+09 -11.7% 3.59e+09 -0.1% 4.061e+09 vm-scalability.workload [1]: https://lore.kernel.org/oe-lkp/72e017b9-deb6-44fa-91d6-716ee2c39cbc@intel.com/T/#m7d2bba30f75a9cee8eab07e5809abd9b3b206c84 Link: https://lkml.kernel.org/r/20230914134741.1937654-1-fengwei.yin@intel.com Fixes: de74976eb65151a2f568e477fc2e0032df5b22b4 ("filemap: add filemap_map_folio_range()") Signed-off-by: Yin Fengwei Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202309111556.b2aa3d7a-oliver.sang@intel.com Cc: Feng Tang Cc: Huang Ying Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- mm/filemap.c | 69 ++++++++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 48 insertions(+), 21 deletions(-) (limited to 'mm') diff --git a/mm/filemap.c b/mm/filemap.c index 582f5317ff71..4ea4387053e8 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3475,13 +3475,11 @@ skip: */ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf, struct folio *folio, unsigned long start, - unsigned long addr, unsigned int nr_pages) + unsigned long addr, unsigned int nr_pages, + unsigned int *mmap_miss) { vm_fault_t ret = 0; - struct vm_area_struct *vma = vmf->vma; - struct file *file = vma->vm_file; struct page *page = folio_page(folio, start); - unsigned int mmap_miss = READ_ONCE(file->f_ra.mmap_miss); unsigned int count = 0; pte_t *old_ptep = vmf->pte; @@ -3489,8 +3487,7 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf, if (PageHWPoison(page + count)) goto skip; - if (mmap_miss > 0) - mmap_miss--; + (*mmap_miss)++; /* * NOTE: If there're PTE markers, we'll leave them to be @@ -3525,7 +3522,35 @@ skip: } vmf->pte = old_ptep; - WRITE_ONCE(file->f_ra.mmap_miss, mmap_miss); + + return ret; +} + +static vm_fault_t filemap_map_order0_folio(struct vm_fault *vmf, + struct folio *folio, unsigned long addr, + unsigned int *mmap_miss) +{ + vm_fault_t ret = 0; + struct page *page = &folio->page; + + if (PageHWPoison(page)) + return ret; + + (*mmap_miss)++; + + /* + * NOTE: If there're PTE markers, we'll leave them to be + * handled in the specific fault path, and it'll prohibit + * the fault-around logic. + */ + if (!pte_none(ptep_get(vmf->pte))) + return ret; + + if (vmf->address == addr) + ret = VM_FAULT_NOPAGE; + + set_pte_range(vmf, folio, page, 1, addr); + folio_ref_inc(folio); return ret; } @@ -3541,7 +3566,7 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf, XA_STATE(xas, &mapping->i_pages, start_pgoff); struct folio *folio; vm_fault_t ret = 0; - int nr_pages = 0; + unsigned int nr_pages = 0, mmap_miss = 0, mmap_miss_saved; rcu_read_lock(); folio = next_uptodate_folio(&xas, mapping, end_pgoff); @@ -3569,25 +3594,27 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf, end = folio->index + folio_nr_pages(folio) - 1; nr_pages = min(end, end_pgoff) - xas.xa_index + 1; - /* - * NOTE: If there're PTE markers, we'll leave them to be - * handled in the specific fault path, and it'll prohibit the - * fault-around logic. - */ - if (!pte_none(ptep_get(vmf->pte))) - goto unlock; - - ret |= filemap_map_folio_range(vmf, folio, - xas.xa_index - folio->index, addr, nr_pages); + if (!folio_test_large(folio)) + ret |= filemap_map_order0_folio(vmf, + folio, addr, &mmap_miss); + else + ret |= filemap_map_folio_range(vmf, folio, + xas.xa_index - folio->index, addr, + nr_pages, &mmap_miss); -unlock: folio_unlock(folio); folio_put(folio); - folio = next_uptodate_folio(&xas, mapping, end_pgoff); - } while (folio); + } while ((folio = next_uptodate_folio(&xas, mapping, end_pgoff)) != NULL); pte_unmap_unlock(vmf->pte, vmf->ptl); out: rcu_read_unlock(); + + mmap_miss_saved = READ_ONCE(file->f_ra.mmap_miss); + if (mmap_miss >= mmap_miss_saved) + WRITE_ONCE(file->f_ra.mmap_miss, 0); + else + WRITE_ONCE(file->f_ra.mmap_miss, mmap_miss_saved - mmap_miss); + return ret; } EXPORT_SYMBOL(filemap_map_pages); -- cgit v1.2.3