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Message-ID: <20240712024455.163543-4-zi.yan@sent.com>
Date: Thu, 11 Jul 2024 22:44:55 -0400
From: Zi Yan <zi.yan@...t.com>
To: David Hildenbrand <david@...hat.com>,
"Huang, Ying" <ying.huang@...el.com>,
linux-mm@...ck.org
Cc: Zi Yan <ziy@...dia.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Baolin Wang <baolin.wang@...ux.alibaba.com>,
linux-kernel@...r.kernel.org
Subject: [RFC PATCH 3/3] mm/migrate: move common code to numa_migrate_check (was numa_migrate_prep)
From: Zi Yan <ziy@...dia.com>
do_numa_page() and do_huge_pmd_numa_page() share a lot of common code. To
reduce redundancy, move common code to numa_migrate_prep() and rename
the function to numa_migrate_check() to reflect its functionality.
There is some code difference between do_numa_page() and
do_huge_pmd_numa_page() before the code move:
1. do_huge_pmd_numa_page() did not check shared folios to set TNF_SHARED.
2. do_huge_pmd_numa_page() did not check and skip zone device folios.
Signed-off-by: Zi Yan <ziy@...dia.com>
---
mm/huge_memory.c | 28 ++++++-----------
mm/internal.h | 5 +--
mm/memory.c | 81 +++++++++++++++++++++++-------------------------
3 files changed, 52 insertions(+), 62 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 8c11d6da4b36..66d67d13e0dc 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1670,10 +1670,10 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
pmd_t pmd;
struct folio *folio;
unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
- int nid = NUMA_NO_NODE;
- int target_nid, last_cpupid = (-1 & LAST_CPUPID_MASK);
+ int target_nid = NUMA_NO_NODE;
+ int last_cpupid = (-1 & LAST_CPUPID_MASK);
bool writable = false;
- int flags = 0;
+ int flags = 0, nr_pages;
vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) {
@@ -1693,21 +1693,13 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
writable = true;
folio = vm_normal_folio_pmd(vma, haddr, pmd);
- if (!folio)
+ if (!folio || folio_is_zone_device(folio))
goto out_map;
- /* See similar comment in do_numa_page for explanation */
- if (!writable)
- flags |= TNF_NO_GROUP;
+ nr_pages = folio_nr_pages(folio);
- 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 (folio_has_cpupid(folio))
- last_cpupid = folio_last_cpupid(folio);
- target_nid = numa_migrate_prep(folio, vmf, haddr, nid, &flags);
+ target_nid = numa_migrate_check(folio, vmf, haddr, writable,
+ &flags, &last_cpupid);
if (target_nid == NUMA_NO_NODE)
goto out_map;
if (migrate_misplaced_folio_prepare(folio, vma, target_nid)) {
@@ -1720,8 +1712,8 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
if (!migrate_misplaced_folio(folio, vma, target_nid)) {
flags |= TNF_MIGRATED;
- nid = target_nid;
} else {
+ target_nid = NUMA_NO_NODE;
flags |= TNF_MIGRATE_FAIL;
vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) {
@@ -1732,8 +1724,8 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
}
out:
- if (nid != NUMA_NO_NODE)
- task_numa_fault(last_cpupid, nid, HPAGE_PMD_NR, flags);
+ if (target_nid != NUMA_NO_NODE)
+ task_numa_fault(last_cpupid, target_nid, nr_pages, flags);
return 0;
diff --git a/mm/internal.h b/mm/internal.h
index b4d86436565b..7782b7bb3383 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1217,8 +1217,9 @@ void vunmap_range_noflush(unsigned long start, unsigned long end);
void __vunmap_range_noflush(unsigned long start, unsigned long end);
-int numa_migrate_prep(struct folio *folio, struct vm_fault *vmf,
- unsigned long addr, int page_nid, int *flags);
+int numa_migrate_check(struct folio *folio, struct vm_fault *vmf,
+ unsigned long addr, bool writable,
+ int *flags, int *last_cpupid);
void free_zone_device_folio(struct folio *folio);
int migrate_device_coherent_page(struct page *page);
diff --git a/mm/memory.c b/mm/memory.c
index 96c2f5b3d796..a252c0f13755 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5209,16 +5209,42 @@ static vm_fault_t do_fault(struct vm_fault *vmf)
return ret;
}
-int numa_migrate_prep(struct folio *folio, struct vm_fault *vmf,
- unsigned long addr, int page_nid, int *flags)
+int numa_migrate_check(struct folio *folio, struct vm_fault *vmf,
+ unsigned long addr, bool writable,
+ int *flags, int *last_cpupid)
{
struct vm_area_struct *vma = vmf->vma;
+ /*
+ * Avoid grouping on RO pages in general. RO pages shouldn't hurt as
+ * much anyway since they can be in shared cache state. This misses
+ * the case where a mapping is writable but the process never writes
+ * to it but pte_write gets cleared during protection updates and
+ * pte_dirty has unpredictable behaviour between PTE scan updates,
+ * background writeback, dirty balancing and application behaviour.
+ */
+ if (!writable)
+ *flags |= TNF_NO_GROUP;
+
+ /*
+ * Flag if the folio is shared between multiple address spaces. This
+ * is later used when determining whether to group tasks together
+ */
+ if (folio_likely_mapped_shared(folio) && (vma->vm_flags & VM_SHARED))
+ *flags |= TNF_SHARED;
+
+ /*
+ * For memory tiering mode, cpupid of slow memory page is used
+ * to record page access time.
+ */
+ if (folio_has_cpupid(folio))
+ *last_cpupid = folio_last_cpupid(folio);
+
/* Record the current PID acceesing VMA */
vma_set_access_pid_bit(vma);
count_vm_numa_event(NUMA_HINT_FAULTS);
- if (page_nid == numa_node_id()) {
+ if (folio_nid(folio) == numa_node_id()) {
count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
*flags |= TNF_FAULT_LOCAL;
}
@@ -5284,12 +5310,11 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
struct folio *folio = NULL;
- int nid = NUMA_NO_NODE;
+ int target_nid = NUMA_NO_NODE;
bool writable = false, ignore_writable = false;
bool pte_write_upgrade = vma_wants_manual_pte_write_upgrade(vma);
- int last_cpupid;
- int target_nid;
- pte_t pte, old_pte;
+ int last_cpupid = (-1 & LAST_CPUPID_MASK);
+ pte_t pte, old_pte = vmf->orig_pte;
int flags = 0, nr_pages;
/*
@@ -5297,10 +5322,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
* table lock, that its contents have not changed during fault handling.
*/
spin_lock(vmf->ptl);
- /* Read the live PTE from the page tables: */
- old_pte = ptep_get(vmf->pte);
-
- if (unlikely(!pte_same(old_pte, vmf->orig_pte))) {
+ if (unlikely(!pte_same(old_pte, *vmf->pte))) {
pte_unmap_unlock(vmf->pte, vmf->ptl);
goto out;
}
@@ -5320,35 +5342,10 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
if (!folio || folio_is_zone_device(folio))
goto out_map;
- /*
- * Avoid grouping on RO pages in general. RO pages shouldn't hurt as
- * much anyway since they can be in shared cache state. This misses
- * the case where a mapping is writable but the process never writes
- * to it but pte_write gets cleared during protection updates and
- * pte_dirty has unpredictable behaviour between PTE scan updates,
- * background writeback, dirty balancing and application behaviour.
- */
- if (!writable)
- flags |= TNF_NO_GROUP;
-
- /*
- * Flag if the folio is shared between multiple address spaces. This
- * is later used when determining whether to group tasks together
- */
- if (folio_likely_mapped_shared(folio) && (vma->vm_flags & VM_SHARED))
- flags |= TNF_SHARED;
-
- nid = folio_nid(folio);
nr_pages = folio_nr_pages(folio);
- /*
- * For memory tiering mode, cpupid of slow memory page is used
- * to record page access time. So use default value.
- */
- if (!folio_has_cpupid(folio))
- last_cpupid = (-1 & LAST_CPUPID_MASK);
- else
- last_cpupid = folio_last_cpupid(folio);
- target_nid = numa_migrate_prep(folio, vmf, vmf->address, nid, &flags);
+
+ target_nid = numa_migrate_check(folio, vmf, vmf->address, writable,
+ &flags, &last_cpupid);
if (target_nid == NUMA_NO_NODE)
goto out_map;
if (migrate_misplaced_folio_prepare(folio, vma, target_nid)) {
@@ -5362,9 +5359,9 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
/* Migrate to the requested node */
if (!migrate_misplaced_folio(folio, vma, target_nid)) {
- nid = target_nid;
flags |= TNF_MIGRATED;
} else {
+ target_nid = NUMA_NO_NODE;
flags |= TNF_MIGRATE_FAIL;
vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
vmf->address, &vmf->ptl);
@@ -5378,8 +5375,8 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
}
out:
- if (nid != NUMA_NO_NODE)
- task_numa_fault(last_cpupid, nid, nr_pages, flags);
+ if (target_nid != NUMA_NO_NODE)
+ task_numa_fault(last_cpupid, target_nid, nr_pages, flags);
return 0;
out_map:
/*
--
2.43.0
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