linux-kernel - [PATCH 03/10] mm: abstract duplicated policy comparison

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Message-ID: <bf56244f473e6ac9378cfce420b51c4dac7783a7.1722849859.git.lorenzo.stoakes@oracle.com>
Date: Mon,  5 Aug 2024 13:13:50 +0100
From: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
To: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>
Cc: "Liam R . Howlett" <Liam.Howlett@...cle.com>,
        Vlastimil Babka <vbabka@...e.cz>
Subject: [PATCH 03/10] mm: abstract duplicated policy comparison

Both can_vma_merge_before() and can_vma_merge_after() are invoked after
checking for compatible VMA NUMA policy, we can simply move this to
is_mergeable_vma() and abstract this altogether.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
---
 mm/mmap.c | 8 +++-----
 mm/vma.c  | 9 ++++-----
 2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index f931000c561f..721ced6e37b0 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1422,8 +1422,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 
 	/* Attempt to expand an old mapping */
 	/* Check next */
-	if (next && next->vm_start == end && !vma_policy(next) &&
-	    can_vma_merge_before(&vmg)) {
+	if (next && next->vm_start == end && can_vma_merge_before(&vmg)) {
 		merge_end = next->vm_end;
 		vma = next;
 		vmg.pgoff = next->vm_pgoff - pglen;
@@ -1435,8 +1434,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 	}
 
 	/* Check prev */
-	if (prev && prev->vm_end == addr && !vma_policy(prev) &&
-	    can_vma_merge_after(&vmg)) {
+	if (prev && prev->vm_end == addr && can_vma_merge_after(&vmg)) {
 		merge_start = prev->vm_start;
 		vma = prev;
 		vmg.pgoff = prev->vm_pgoff;
@@ -1798,7 +1796,7 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
 	 * Expand the existing vma if possible; Note that singular lists do not
 	 * occur after forking, so the expand will only happen on new VMAs.
 	 */
-	if (vma && vma->vm_end == addr && !vma_policy(vma)) {
+	if (vma && vma->vm_end == addr) {
 		struct vma_merge_struct vmg = {
 			.prev = vma,
 			.flags = flags,
diff --git a/mm/vma.c b/mm/vma.c
index 20c4ce7712c0..b452b472a085 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -19,6 +19,8 @@ static inline bool is_mergeable_vma(struct vma_merge_struct *vmg, bool merge_nex
 	 */
 	bool may_remove_vma = merge_next;
 
+	if (!mpol_equal(vmg->policy, vma_policy(vma)))
+		return false;
 	/*
 	 * VM_SOFTDIRTY should not prevent from VMA merging, if we
 	 * match the flags but dirty bit -- the caller should mark
@@ -971,17 +973,14 @@ static struct vm_area_struct *vma_merge(struct vma_merge_struct *vmg)
 		vma_pgoff = prev->vm_pgoff;
 
 		/* Can we merge the predecessor? */
-		if (addr == prev->vm_end && mpol_equal(vma_policy(prev), vmg->policy)
-		    && can_vma_merge_after(vmg)) {
-
+		if (addr == prev->vm_end && can_vma_merge_after(vmg)) {
 			merge_prev = true;
 			vma_prev(vmg->vmi);
 		}
 	}
 
 	/* Can we merge the successor? */
-	if (next && mpol_equal(vmg->policy, vma_policy(next)) &&
-	    can_vma_merge_before(vmg)) {
+	if (next && can_vma_merge_before(vmg)) {
 		merge_next = true;
 	}
 
-- 
2.45.2