Commit d0cf3dd4 authored by Liam R. Howlett's avatar Liam R. Howlett Committed by Andrew Morton

damon: convert __damon_va_three_regions to use the VMA iterator

This rather specialised walk can use the VMA iterator.  If this proves to
be too slow, we can write a custom routine to find the two largest gaps,
but it will be somewhat complicated, so let's see if we need it first.

Update the kunit test case to use the maple tree.  This also fixes an
issue with the kunit testcase not adding the last VMA to the list.

Link: https://lkml.kernel.org/r/20220906194824.2110408-16-Liam.Howlett@oracle.com
Fixes: 17ccae8b (mm/damon: add kunit tests)
Signed-off-by: default avatarLiam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarSeongJae Park <sj@kernel.org>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Tested-by: default avatarYu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent c9dbe82c
...@@ -14,33 +14,19 @@ ...@@ -14,33 +14,19 @@
#include <kunit/test.h> #include <kunit/test.h>
static void __link_vmas(struct vm_area_struct *vmas, ssize_t nr_vmas) static void __link_vmas(struct maple_tree *mt, struct vm_area_struct *vmas,
ssize_t nr_vmas)
{ {
int i, j; int i;
unsigned long largest_gap, gap; MA_STATE(mas, mt, 0, 0);
if (!nr_vmas) if (!nr_vmas)
return; return;
for (i = 0; i < nr_vmas - 1; i++) { mas_lock(&mas);
vmas[i].vm_next = &vmas[i + 1]; for (i = 0; i < nr_vmas; i++)
vma_mas_store(&vmas[i], &mas);
vmas[i].vm_rb.rb_left = NULL; mas_unlock(&mas);
vmas[i].vm_rb.rb_right = &vmas[i + 1].vm_rb;
largest_gap = 0;
for (j = i; j < nr_vmas; j++) {
if (j == 0)
continue;
gap = vmas[j].vm_start - vmas[j - 1].vm_end;
if (gap > largest_gap)
largest_gap = gap;
}
vmas[i].rb_subtree_gap = largest_gap;
}
vmas[i].vm_next = NULL;
vmas[i].vm_rb.rb_right = NULL;
vmas[i].rb_subtree_gap = 0;
} }
/* /*
...@@ -72,6 +58,7 @@ static void __link_vmas(struct vm_area_struct *vmas, ssize_t nr_vmas) ...@@ -72,6 +58,7 @@ static void __link_vmas(struct vm_area_struct *vmas, ssize_t nr_vmas)
*/ */
static void damon_test_three_regions_in_vmas(struct kunit *test) static void damon_test_three_regions_in_vmas(struct kunit *test)
{ {
static struct mm_struct mm;
struct damon_addr_range regions[3] = {0,}; struct damon_addr_range regions[3] = {0,};
/* 10-20-25, 200-210-220, 300-305, 307-330 */ /* 10-20-25, 200-210-220, 300-305, 307-330 */
struct vm_area_struct vmas[] = { struct vm_area_struct vmas[] = {
...@@ -83,9 +70,10 @@ static void damon_test_three_regions_in_vmas(struct kunit *test) ...@@ -83,9 +70,10 @@ static void damon_test_three_regions_in_vmas(struct kunit *test)
(struct vm_area_struct) {.vm_start = 307, .vm_end = 330}, (struct vm_area_struct) {.vm_start = 307, .vm_end = 330},
}; };
__link_vmas(vmas, 6); mt_init_flags(&mm.mm_mt, MM_MT_FLAGS);
__link_vmas(&mm.mm_mt, vmas, ARRAY_SIZE(vmas));
__damon_va_three_regions(&vmas[0], regions); __damon_va_three_regions(&mm, regions);
KUNIT_EXPECT_EQ(test, 10ul, regions[0].start); KUNIT_EXPECT_EQ(test, 10ul, regions[0].start);
KUNIT_EXPECT_EQ(test, 25ul, regions[0].end); KUNIT_EXPECT_EQ(test, 25ul, regions[0].end);
......
...@@ -113,37 +113,38 @@ static unsigned long sz_range(struct damon_addr_range *r) ...@@ -113,37 +113,38 @@ static unsigned long sz_range(struct damon_addr_range *r)
* *
* Returns 0 if success, or negative error code otherwise. * Returns 0 if success, or negative error code otherwise.
*/ */
static int __damon_va_three_regions(struct vm_area_struct *vma, static int __damon_va_three_regions(struct mm_struct *mm,
struct damon_addr_range regions[3]) struct damon_addr_range regions[3])
{ {
struct damon_addr_range gap = {0}, first_gap = {0}, second_gap = {0}; struct damon_addr_range first_gap = {0}, second_gap = {0};
struct vm_area_struct *last_vma = NULL; VMA_ITERATOR(vmi, mm, 0);
unsigned long start = 0; struct vm_area_struct *vma, *prev = NULL;
struct rb_root rbroot; unsigned long start;
/* Find two biggest gaps so that first_gap > second_gap > others */
for (; vma; vma = vma->vm_next) {
if (!last_vma) {
start = vma->vm_start;
goto next;
}
if (vma->rb_subtree_gap <= sz_range(&second_gap)) { /*
rbroot.rb_node = &vma->vm_rb; * Find the two biggest gaps so that first_gap > second_gap > others.
vma = rb_entry(rb_last(&rbroot), * If this is too slow, it can be optimised to examine the maple
struct vm_area_struct, vm_rb); * tree gaps.
*/
for_each_vma(vmi, vma) {
unsigned long gap;
if (!prev) {
start = vma->vm_start;
goto next; goto next;
} }
gap = vma->vm_start - prev->vm_end;
gap.start = last_vma->vm_end;
gap.end = vma->vm_start; if (gap > sz_range(&first_gap)) {
if (sz_range(&gap) > sz_range(&second_gap)) { second_gap = first_gap;
swap(gap, second_gap); first_gap.start = prev->vm_end;
if (sz_range(&second_gap) > sz_range(&first_gap)) first_gap.end = vma->vm_start;
swap(second_gap, first_gap); } else if (gap > sz_range(&second_gap)) {
second_gap.start = prev->vm_end;
second_gap.end = vma->vm_start;
} }
next: next:
last_vma = vma; prev = vma;
} }
if (!sz_range(&second_gap) || !sz_range(&first_gap)) if (!sz_range(&second_gap) || !sz_range(&first_gap))
...@@ -159,7 +160,7 @@ static int __damon_va_three_regions(struct vm_area_struct *vma, ...@@ -159,7 +160,7 @@ static int __damon_va_three_regions(struct vm_area_struct *vma,
regions[1].start = ALIGN(first_gap.end, DAMON_MIN_REGION); regions[1].start = ALIGN(first_gap.end, DAMON_MIN_REGION);
regions[1].end = ALIGN(second_gap.start, DAMON_MIN_REGION); regions[1].end = ALIGN(second_gap.start, DAMON_MIN_REGION);
regions[2].start = ALIGN(second_gap.end, DAMON_MIN_REGION); regions[2].start = ALIGN(second_gap.end, DAMON_MIN_REGION);
regions[2].end = ALIGN(last_vma->vm_end, DAMON_MIN_REGION); regions[2].end = ALIGN(prev->vm_end, DAMON_MIN_REGION);
return 0; return 0;
} }
...@@ -180,7 +181,7 @@ static int damon_va_three_regions(struct damon_target *t, ...@@ -180,7 +181,7 @@ static int damon_va_three_regions(struct damon_target *t,
return -EINVAL; return -EINVAL;
mmap_read_lock(mm); mmap_read_lock(mm);
rc = __damon_va_three_regions(mm->mmap, regions); rc = __damon_va_three_regions(mm, regions);
mmap_read_unlock(mm); mmap_read_unlock(mm);
mmput(mm); mmput(mm);
......
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