From: Barry Song <21cnbao@gmail.com>
To: akpm@linux-foundation.org, linux-mm@kvack.org
Cc: baolin.wang@linux.alibaba.com, chrisl@kernel.org,
david@redhat.com, hanchuanhua@oppo.com, hannes@cmpxchg.org,
hughd@google.com, kasong@tencent.com,
linux-kernel@vger.kernel.org, ryan.roberts@arm.com,
surenb@google.com, v-songbaohua@oppo.com, willy@infradead.org,
xiang@kernel.org, ying.huang@intel.com, yosryahmed@google.com,
yuzhao@google.com, ziy@nvidia.com
Subject: [PATCH v4 6/6] mm: swap: entirely map large folios found in swapcache
Date: Thu, 9 May 2024 10:40:40 +1200 [thread overview]
Message-ID: <20240508224040.190469-7-21cnbao@gmail.com> (raw)
In-Reply-To: <20240508224040.190469-1-21cnbao@gmail.com>
From: Chuanhua Han <hanchuanhua@oppo.com>
When a large folio is found in the swapcache, the current implementation
requires calling do_swap_page() nr_pages times, resulting in nr_pages
page faults. This patch opts to map the entire large folio at once to
minimize page faults. Additionally, redundant checks and early exits
for ARM64 MTE restoring are removed.
Signed-off-by: Chuanhua Han <hanchuanhua@oppo.com>
Co-developed-by: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
---
mm/memory.c | 59 +++++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 48 insertions(+), 11 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index d9434df24d62..8b9e4cab93ed 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3968,6 +3968,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
pte_t pte;
vm_fault_t ret = 0;
void *shadow = NULL;
+ int nr_pages;
+ unsigned long page_idx;
+ unsigned long address;
+ pte_t *ptep;
if (!pte_unmap_same(vmf))
goto out;
@@ -4166,6 +4170,38 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
goto out_nomap;
}
+ nr_pages = 1;
+ page_idx = 0;
+ address = vmf->address;
+ ptep = vmf->pte;
+ if (folio_test_large(folio) && folio_test_swapcache(folio)) {
+ int nr = folio_nr_pages(folio);
+ unsigned long idx = folio_page_idx(folio, page);
+ unsigned long folio_start = address - idx * PAGE_SIZE;
+ unsigned long folio_end = folio_start + nr * PAGE_SIZE;
+ pte_t *folio_ptep;
+ pte_t folio_pte;
+
+ if (unlikely(folio_start < max(address & PMD_MASK, vma->vm_start)))
+ goto check_folio;
+ if (unlikely(folio_end > pmd_addr_end(address, vma->vm_end)))
+ goto check_folio;
+
+ folio_ptep = vmf->pte - idx;
+ folio_pte = ptep_get(folio_ptep);
+ if (!pte_same(folio_pte, pte_move_swp_offset(vmf->orig_pte, -idx)) ||
+ swap_pte_batch(folio_ptep, nr, folio_pte) != nr)
+ goto check_folio;
+
+ page_idx = idx;
+ address = folio_start;
+ ptep = folio_ptep;
+ nr_pages = nr;
+ entry = folio->swap;
+ page = &folio->page;
+ }
+
+check_folio:
/*
* PG_anon_exclusive reuses PG_mappedtodisk for anon pages. A swap pte
* must never point at an anonymous page in the swapcache that is
@@ -4225,12 +4261,12 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
* We're already holding a reference on the page but haven't mapped it
* yet.
*/
- swap_free(entry);
+ swap_free_nr(entry, nr_pages);
if (should_try_to_free_swap(folio, vma, vmf->flags))
folio_free_swap(folio);
- inc_mm_counter(vma->vm_mm, MM_ANONPAGES);
- dec_mm_counter(vma->vm_mm, MM_SWAPENTS);
+ add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr_pages);
+ add_mm_counter(vma->vm_mm, MM_SWAPENTS, -nr_pages);
pte = mk_pte(page, vma->vm_page_prot);
/*
@@ -4247,27 +4283,28 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
}
rmap_flags |= RMAP_EXCLUSIVE;
}
- flush_icache_page(vma, page);
+ folio_ref_add(folio, nr_pages - 1);
+ flush_icache_pages(vma, page, nr_pages);
if (pte_swp_soft_dirty(vmf->orig_pte))
pte = pte_mksoft_dirty(pte);
if (pte_swp_uffd_wp(vmf->orig_pte))
pte = pte_mkuffd_wp(pte);
- vmf->orig_pte = pte;
+ vmf->orig_pte = pte_advance_pfn(pte, page_idx);
/* ksm created a completely new copy */
if (unlikely(folio != swapcache && swapcache)) {
- folio_add_new_anon_rmap(folio, vma, vmf->address);
+ folio_add_new_anon_rmap(folio, vma, address);
folio_add_lru_vma(folio, vma);
} else {
- folio_add_anon_rmap_pte(folio, page, vma, vmf->address,
+ folio_add_anon_rmap_ptes(folio, page, nr_pages, vma, address,
rmap_flags);
}
VM_BUG_ON(!folio_test_anon(folio) ||
(pte_write(pte) && !PageAnonExclusive(page)));
- set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte);
- arch_do_swap_page_nr(vma->vm_mm, vma, vmf->address,
- pte, vmf->orig_pte, 1);
+ set_ptes(vma->vm_mm, address, ptep, pte, nr_pages);
+ arch_do_swap_page_nr(vma->vm_mm, vma, address,
+ pte, pte, nr_pages);
folio_unlock(folio);
if (folio != swapcache && swapcache) {
@@ -4291,7 +4328,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
}
/* No need to invalidate - it was non-present before */
- update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1);
+ update_mmu_cache_range(vmf, vma, address, ptep, nr_pages);
unlock:
if (vmf->pte)
pte_unmap_unlock(vmf->pte, vmf->ptl);
--
2.34.1
next prev parent reply other threads:[~2024-05-08 22:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-08 22:40 [PATCH v4 0/6] large folios swap-in: handle refault cases first Barry Song
2024-05-08 22:40 ` [PATCH v4 1/6] mm: swap: introduce swap_free_nr() for batched swap_free() Barry Song
2024-05-08 22:40 ` [PATCH v4 2/6] mm: remove the implementation of swap_free() and always use swap_free_nr() Barry Song
2024-05-10 9:11 ` Ryan Roberts
2024-05-08 22:40 ` [PATCH v4 3/6] mm: introduce pte_move_swp_offset() helper which can move offset bidirectionally Barry Song
2024-05-08 22:40 ` [PATCH v4 4/6] mm: introduce arch_do_swap_page_nr() which allows restore metadata for nr pages Barry Song
2024-05-08 22:40 ` [PATCH v4 5/6] mm: swap: make should_try_to_free_swap() support large-folio Barry Song
2024-05-08 22:40 ` Barry Song [this message]
2024-05-09 7:44 ` [PATCH v4 6/6] mm: swap: entirely map large folios found in swapcache Huang, Ying
2024-05-21 21:21 ` [PATCH v4 0/6] large folios swap-in: handle refault cases first Barry Song
2024-05-21 21:59 ` Andrew Morton
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