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	Replace the refreshed 5.15 backports with backports for 6.1. This fixes FMODE_CAN_ODIRECT having the same value as FMODE_NOREUSE. Signed-off-by: Kazuki Hashimoto <kazukih0205@gmail.com>
		
			
				
	
	
		
			203 lines
		
	
	
		
			6.6 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			203 lines
		
	
	
		
			6.6 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
From 70d216c71ff5c5b17dd1da6294f97b91fb6aba7a Mon Sep 17 00:00:00 2001
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From: Yu Zhao <yuzhao@google.com>
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Date: Fri, 30 Dec 2022 14:52:51 -0700
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Subject: [PATCH 10/19] UPSTREAM: mm: add vma_has_recency()
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Add vma_has_recency() to indicate whether a VMA may exhibit temporal
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locality that the LRU algorithm relies on.
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This function returns false for VMAs marked by VM_SEQ_READ or
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VM_RAND_READ.  While the former flag indicates linear access, i.e., a
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special case of spatial locality, both flags indicate a lack of temporal
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locality, i.e., the reuse of an area within a relatively small duration.
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"Recency" is chosen over "locality" to avoid confusion between temporal
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and spatial localities.
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Before this patch, the active/inactive LRU only ignored the accessed bit
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from VMAs marked by VM_SEQ_READ.  After this patch, the active/inactive
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LRU and MGLRU share the same logic: they both ignore the accessed bit if
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vma_has_recency() returns false.
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For the active/inactive LRU, the following fio test showed a [6, 8]%
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increase in IOPS when randomly accessing mapped files under memory
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pressure.
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  kb=$(awk '/MemTotal/ { print $2 }' /proc/meminfo)
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  kb=$((kb - 8*1024*1024))
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  modprobe brd rd_nr=1 rd_size=$kb
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  dd if=/dev/zero of=/dev/ram0 bs=1M
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  mkfs.ext4 /dev/ram0
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  mount /dev/ram0 /mnt/
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  swapoff -a
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  fio --name=test --directory=/mnt/ --ioengine=mmap --numjobs=8 \
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      --size=8G --rw=randrw --time_based --runtime=10m \
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      --group_reporting
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The discussion that led to this patch is here [1].  Additional test
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results are available in that thread.
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[1] https://lore.kernel.org/r/Y31s%2FK8T85jh05wH@google.com/
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Link: https://lkml.kernel.org/r/20221230215252.2628425-1-yuzhao@google.com
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Change-Id: I291dcb795197659e40e46539cd32b857677c34ad
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Signed-off-by: Yu Zhao <yuzhao@google.com>
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Cc: Alexander Viro <viro@zeniv.linux.org.uk>
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Cc: Andrea Righi <andrea.righi@canonical.com>
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Cc: Johannes Weiner <hannes@cmpxchg.org>
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Cc: Michael Larabel <Michael@MichaelLarabel.com>
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Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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(cherry picked from commit 8788f6781486769d9598dcaedc3fe0eb12fc3e59)
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Bug: 274865848
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Signed-off-by: T.J. Mercier <tjmercier@google.com>
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---
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 include/linux/mm_inline.h |  8 ++++++++
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 mm/memory.c               |  7 +++----
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 mm/rmap.c                 | 42 +++++++++++++++++----------------------
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 mm/vmscan.c               |  5 ++++-
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 4 files changed, 33 insertions(+), 29 deletions(-)
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diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
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index c1fd3922dc5dd..7bb2e5f94734c 100644
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--- a/include/linux/mm_inline.h
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+++ b/include/linux/mm_inline.h
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@@ -595,4 +595,12 @@ pte_install_uffd_wp_if_needed(struct vm_area_struct *vma, unsigned long addr,
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 #endif
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 }
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+static inline bool vma_has_recency(struct vm_area_struct *vma)
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+{
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+	if (vma->vm_flags & (VM_SEQ_READ | VM_RAND_READ))
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+		return false;
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+
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+	return true;
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+}
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+
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 #endif
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diff --git a/mm/memory.c b/mm/memory.c
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index 747b7ea30f890..c2f48f8003c2e 100644
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--- a/mm/memory.c
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+++ b/mm/memory.c
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@@ -1435,8 +1435,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
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 					force_flush = 1;
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 					set_page_dirty(page);
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 				}
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-				if (pte_young(ptent) &&
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-				    likely(!(vma->vm_flags & VM_SEQ_READ)))
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+				if (pte_young(ptent) && likely(vma_has_recency(vma)))
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 					mark_page_accessed(page);
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 			}
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 			rss[mm_counter(page)]--;
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@@ -5170,8 +5169,8 @@ static inline void mm_account_fault(struct pt_regs *regs,
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 #ifdef CONFIG_LRU_GEN
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 static void lru_gen_enter_fault(struct vm_area_struct *vma)
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 {
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-	/* the LRU algorithm doesn't apply to sequential or random reads */
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-	current->in_lru_fault = !(vma->vm_flags & (VM_SEQ_READ | VM_RAND_READ));
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+	/* the LRU algorithm only applies to accesses with recency */
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+	current->in_lru_fault = vma_has_recency(vma);
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 }
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 static void lru_gen_exit_fault(void)
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diff --git a/mm/rmap.c b/mm/rmap.c
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index 7da2d8d097d9b..825dac3caa1e5 100644
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--- a/mm/rmap.c
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+++ b/mm/rmap.c
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@@ -823,25 +823,14 @@ static bool folio_referenced_one(struct folio *folio,
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 		}
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 		if (pvmw.pte) {
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-			if (lru_gen_enabled() && pte_young(*pvmw.pte) &&
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-			    !(vma->vm_flags & (VM_SEQ_READ | VM_RAND_READ))) {
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+			if (lru_gen_enabled() && pte_young(*pvmw.pte)) {
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 				lru_gen_look_around(&pvmw);
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 				referenced++;
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 			}
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 			if (ptep_clear_flush_young_notify(vma, address,
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-						pvmw.pte)) {
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-				/*
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-				 * Don't treat a reference through
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-				 * a sequentially read mapping as such.
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-				 * If the folio has been used in another mapping,
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-				 * we will catch it; if this other mapping is
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-				 * already gone, the unmap path will have set
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-				 * the referenced flag or activated the folio.
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-				 */
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-				if (likely(!(vma->vm_flags & VM_SEQ_READ)))
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-					referenced++;
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-			}
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+						pvmw.pte))
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+				referenced++;
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 		} else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
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 			if (pmdp_clear_flush_young_notify(vma, address,
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 						pvmw.pmd))
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@@ -875,7 +864,20 @@ static bool invalid_folio_referenced_vma(struct vm_area_struct *vma, void *arg)
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 	struct folio_referenced_arg *pra = arg;
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 	struct mem_cgroup *memcg = pra->memcg;
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-	if (!mm_match_cgroup(vma->vm_mm, memcg))
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+	/*
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+	 * Ignore references from this mapping if it has no recency. If the
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+	 * folio has been used in another mapping, we will catch it; if this
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+	 * other mapping is already gone, the unmap path will have set the
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+	 * referenced flag or activated the folio in zap_pte_range().
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+	 */
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+	if (!vma_has_recency(vma))
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+		return true;
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+
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+	/*
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+	 * If we are reclaiming on behalf of a cgroup, skip counting on behalf
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+	 * of references from different cgroups.
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+	 */
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+	if (memcg && !mm_match_cgroup(vma->vm_mm, memcg))
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 		return true;
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 	return false;
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@@ -906,6 +908,7 @@ int folio_referenced(struct folio *folio, int is_locked,
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 		.arg = (void *)&pra,
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 		.anon_lock = folio_lock_anon_vma_read,
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 		.try_lock = true,
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+		.invalid_vma = invalid_folio_referenced_vma,
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 	};
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 	*vm_flags = 0;
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@@ -921,15 +924,6 @@ int folio_referenced(struct folio *folio, int is_locked,
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 			return 1;
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 	}
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-	/*
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-	 * If we are reclaiming on behalf of a cgroup, skip
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-	 * counting on behalf of references from different
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-	 * cgroups
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-	 */
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-	if (memcg) {
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-		rwc.invalid_vma = invalid_folio_referenced_vma;
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-	}
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-
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 	rmap_walk(folio, &rwc);
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 	*vm_flags = pra.vm_flags;
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diff --git a/mm/vmscan.c b/mm/vmscan.c
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index 49da02f841c81..596fed6ae0439 100644
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--- a/mm/vmscan.c
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+++ b/mm/vmscan.c
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@@ -3778,7 +3778,10 @@ static int should_skip_vma(unsigned long start, unsigned long end, struct mm_wal
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 	if (is_vm_hugetlb_page(vma))
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 		return true;
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-	if (vma->vm_flags & (VM_LOCKED | VM_SPECIAL | VM_SEQ_READ | VM_RAND_READ))
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+	if (!vma_has_recency(vma))
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+		return true;
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+
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+	if (vma->vm_flags & (VM_LOCKED | VM_SPECIAL))
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 		return true;
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 	if (vma == get_gate_vma(vma->vm_mm))
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-- 
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2.40.1
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