[PATCH 4/6] mm: memory: use a folio in do_numa_page()

From: Kefeng Wang
Date: Mon Sep 18 2023 - 06:34:00 EST


Numa balancing only try to migrate non-compound page in do_numa_page(),
use a folio in it to save several compound_head calls, note we use
folio_estimated_sharers(), it is enough to check the folio sharers
since only normal page is handled, if large folio numa balancing is
supported, a precise folio sharers check would be used, no functional
change intended.

Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
mm/memory.c | 33 ++++++++++++++++-----------------
1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index ce7d9d9eddc4..ce3efe7255d2 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4737,8 +4737,8 @@ int numa_migrate_prep(struct folio *folio, struct vm_area_struct *vma,
static vm_fault_t do_numa_page(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
- struct page *page = NULL;
- int page_nid = NUMA_NO_NODE;
+ struct folio *folio = NULL;
+ int nid = NUMA_NO_NODE;
bool writable = false;
int last_cpupid;
int target_nid;
@@ -4769,12 +4769,12 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
can_change_pte_writable(vma, vmf->address, pte))
writable = true;

- page = vm_normal_page(vma, vmf->address, pte);
- if (!page || is_zone_device_page(page))
+ folio = vm_normal_folio(vma, vmf->address, pte);
+ if (!folio || folio_is_zone_device(folio))
goto out_map;

/* TODO: handle PTE-mapped THP */
- if (PageCompound(page))
+ if (folio_test_large(folio))
goto out_map;

/*
@@ -4789,34 +4789,33 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
flags |= TNF_NO_GROUP;

/*
- * Flag if the page is shared between multiple address spaces. This
+ * Flag if the folio is shared between multiple address spaces. This
* is later used when determining whether to group tasks together
*/
- if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED))
+ if (folio_estimated_sharers(folio) > 1 && (vma->vm_flags & VM_SHARED))
flags |= TNF_SHARED;

- page_nid = page_to_nid(page);
+ nid = folio_nid(folio);
/*
* For memory tiering mode, cpupid of slow memory page is used
* to record page access time. So use default value.
*/
if ((sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) &&
- !node_is_toptier(page_nid))
+ !node_is_toptier(nid))
last_cpupid = (-1 & LAST_CPUPID_MASK);
else
- last_cpupid = page_cpupid_last(page);
- target_nid = numa_migrate_prep(page_folio(page), vma, vmf->address,
- page_nid, &flags);
+ last_cpupid = page_cpupid_last(&folio->page);
+ target_nid = numa_migrate_prep(folio, vma, vmf->address, nid, &flags);
if (target_nid == NUMA_NO_NODE) {
- put_page(page);
+ folio_put(folio);
goto out_map;
}
pte_unmap_unlock(vmf->pte, vmf->ptl);
writable = false;

/* Migrate to the requested node */
- if (migrate_misplaced_folio(page_folio(page), vma, target_nid)) {
- page_nid = target_nid;
+ if (migrate_misplaced_folio(folio, vma, target_nid)) {
+ nid = target_nid;
flags |= TNF_MIGRATED;
} else {
flags |= TNF_MIGRATE_FAIL;
@@ -4832,8 +4831,8 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
}

out:
- if (page_nid != NUMA_NO_NODE)
- task_numa_fault(last_cpupid, page_nid, 1, flags);
+ if (nid != NUMA_NO_NODE)
+ task_numa_fault(last_cpupid, nid, 1, flags);
return 0;
out_map:
/*
--
2.27.0