mm: remove vmacache

By using the maple tree and the maple tree state, the vmacache is no
longer beneficial and is complicating the VMA code.  Remove the vmacache
to reduce the work in keeping it up to date and code complexity.

Link: https://lkml.kernel.org/r/20220906194824.2110408-26-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 4 insertions, 33 deletions

diff --git a/mm/nommu.c b/mm/nommu.c
index 2702790d05d3..265a444a2cc2 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -19,7 +19,6 @@
 #include <linux/export.h>
 #include <linux/mm.h>
 #include <linux/sched/mm.h>
-#include <linux/vmacache.h>
 #include <linux/mman.h>
 #include <linux/swap.h>
 #include <linux/file.h>
@@ -598,23 +597,12 @@ static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
  */
 static void delete_vma_from_mm(struct vm_area_struct *vma)
 {
-	int i;
-	struct address_space *mapping;
-	struct mm_struct *mm = vma->vm_mm;
-	struct task_struct *curr = current;
 	MA_STATE(mas, &vma->vm_mm->mm_mt, 0, 0);
 
-	mm->map_count--;
-	for (i = 0; i < VMACACHE_SIZE; i++) {
-		/* if the vma is cached, invalidate the entire cache */
-		if (curr->vmacache.vmas[i] == vma) {
-			vmacache_invalidate(mm);
-			break;
-		}
-	}
-
+	vma->vm_mm->map_count--;
 	/* remove the VMA from the mapping */
 	if (vma->vm_file) {
+		struct address_space *mapping;
 		mapping = vma->vm_file->f_mapping;
 
 		i_mmap_lock_write(mapping);
@@ -626,7 +614,7 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
 
 	/* remove from the MM's tree and list */
 	vma_mas_remove(vma, &mas);
-	__vma_unlink_list(mm, vma);
+	__vma_unlink_list(vma->vm_mm, vma);
 }
 
 /*
@@ -659,20 +647,9 @@ EXPORT_SYMBOL(find_vma_intersection);
  */
 struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
 {
-	struct vm_area_struct *vma;
 	MA_STATE(mas, &mm->mm_mt, addr, addr);
 
-	/* check the cache first */
-	vma = vmacache_find(mm, addr);
-	if (likely(vma))
-		return vma;
-
-	vma = mas_walk(&mas);
-
-	if (vma)
-		vmacache_update(addr, vma);
-
-	return vma;
+	return mas_walk(&mas);
 }
 EXPORT_SYMBOL(find_vma);
 
@@ -706,11 +683,6 @@ static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
 	unsigned long end = addr + len;
 	MA_STATE(mas, &mm->mm_mt, addr, addr);
 
-	/* check the cache first */
-	vma = vmacache_find_exact(mm, addr, end);
-	if (vma)
-		return vma;
-
 	vma = mas_walk(&mas);
 	if (!vma)
 		return NULL;
@@ -719,7 +691,6 @@ static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
 	if (vma->vm_end != end)
 		return NULL;
 
-	vmacache_update(addr, vma);
 	return vma;
 }