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-rw-r--r--mm/huge_memory.c133
1 files changed, 100 insertions, 33 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index cca80d96e50..0556c6a4495 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -27,11 +27,12 @@
#include "internal.h"
/*
- * By default transparent hugepage support is enabled for all mappings
- * and khugepaged scans all mappings. Defrag is only invoked by
- * khugepaged hugepage allocations and by page faults inside
- * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived
- * allocations.
+ * By default transparent hugepage support is disabled in order that avoid
+ * to risk increase the memory footprint of applications without a guaranteed
+ * benefit. When transparent hugepage support is enabled, is for all mappings,
+ * and khugepaged scans all mappings.
+ * Defrag is invoked by khugepaged hugepage allocations and by page faults
+ * for all hugepage allocations.
*/
unsigned long transparent_hugepage_flags __read_mostly =
#ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS
@@ -758,14 +759,6 @@ static inline struct page *alloc_hugepage_vma(int defrag,
HPAGE_PMD_ORDER, vma, haddr, nd);
}
-#ifndef CONFIG_NUMA
-static inline struct page *alloc_hugepage(int defrag)
-{
- return alloc_pages(alloc_hugepage_gfpmask(defrag, 0),
- HPAGE_PMD_ORDER);
-}
-#endif
-
static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
struct page *zero_page)
@@ -1282,19 +1275,32 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct page *page;
unsigned long haddr = addr & HPAGE_PMD_MASK;
int page_nid = -1, this_nid = numa_node_id();
- int target_nid;
+ int target_nid, last_cpupid = -1;
bool page_locked;
bool migrated = false;
+ int flags = 0;
spin_lock(&mm->page_table_lock);
if (unlikely(!pmd_same(pmd, *pmdp)))
goto out_unlock;
page = pmd_page(pmd);
+ BUG_ON(is_huge_zero_page(page));
page_nid = page_to_nid(page);
+ last_cpupid = page_cpupid_last(page);
count_vm_numa_event(NUMA_HINT_FAULTS);
- if (page_nid == this_nid)
+ if (page_nid == this_nid) {
count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
+ flags |= TNF_FAULT_LOCAL;
+ }
+
+ /*
+ * Avoid grouping on DSO/COW pages in specific and RO pages
+ * in general, RO pages shouldn't hurt as much anyway since
+ * they can be in shared cache state.
+ */
+ if (!pmd_write(pmd))
+ flags |= TNF_NO_GROUP;
/*
* Acquire the page lock to serialise THP migrations but avoid dropping
@@ -1325,7 +1331,7 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
lock_page(page);
anon_vma = page_lock_anon_vma_read(page);
- /* Confirm the PTE did not while locked */
+ /* Confirm the PMD did not change while page_table_lock was released */
spin_lock(&mm->page_table_lock);
if (unlikely(!pmd_same(pmd, *pmdp))) {
unlock_page(page);
@@ -1341,8 +1347,10 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
spin_unlock(&mm->page_table_lock);
migrated = migrate_misplaced_transhuge_page(mm, vma,
pmdp, pmd, addr, page, target_nid);
- if (migrated)
+ if (migrated) {
+ flags |= TNF_MIGRATED;
page_nid = target_nid;
+ }
goto out;
clear_pmdnuma:
@@ -1360,7 +1368,7 @@ out:
page_unlock_anon_vma_read(anon_vma);
if (page_nid != -1)
- task_numa_fault(page_nid, HPAGE_PMD_NR, migrated);
+ task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, flags);
return 0;
}
@@ -1458,6 +1466,12 @@ out:
return ret;
}
+/*
+ * Returns
+ * - 0 if PMD could not be locked
+ * - 1 if PMD was locked but protections unchange and TLB flush unnecessary
+ * - HPAGE_PMD_NR is protections changed and TLB flush necessary
+ */
int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, pgprot_t newprot, int prot_numa)
{
@@ -1466,22 +1480,34 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
if (__pmd_trans_huge_lock(pmd, vma) == 1) {
pmd_t entry;
- entry = pmdp_get_and_clear(mm, addr, pmd);
+ ret = 1;
if (!prot_numa) {
+ entry = pmdp_get_and_clear(mm, addr, pmd);
entry = pmd_modify(entry, newprot);
+ ret = HPAGE_PMD_NR;
BUG_ON(pmd_write(entry));
} else {
struct page *page = pmd_page(*pmd);
- /* only check non-shared pages */
- if (page_mapcount(page) == 1 &&
+ /*
+ * Do not trap faults against the zero page. The
+ * read-only data is likely to be read-cached on the
+ * local CPU cache and it is less useful to know about
+ * local vs remote hits on the zero page.
+ */
+ if (!is_huge_zero_page(page) &&
!pmd_numa(*pmd)) {
+ entry = pmdp_get_and_clear(mm, addr, pmd);
entry = pmd_mknuma(entry);
+ ret = HPAGE_PMD_NR;
}
}
- set_pmd_at(mm, addr, pmd, entry);
+
+ /* Set PMD if cleared earlier */
+ if (ret == HPAGE_PMD_NR)
+ set_pmd_at(mm, addr, pmd, entry);
+
spin_unlock(&vma->vm_mm->page_table_lock);
- ret = 1;
}
return ret;
@@ -1662,7 +1688,7 @@ static void __split_huge_page_refcount(struct page *page,
page_tail->mapping = page->mapping;
page_tail->index = page->index + i;
- page_nid_xchg_last(page_tail, page_nid_last(page));
+ page_cpupid_xchg_last(page_tail, page_cpupid_last(page));
BUG_ON(!PageAnon(page_tail));
BUG_ON(!PageUptodate(page_tail));
@@ -2165,7 +2191,34 @@ static void khugepaged_alloc_sleep(void)
msecs_to_jiffies(khugepaged_alloc_sleep_millisecs));
}
+static int khugepaged_node_load[MAX_NUMNODES];
+
#ifdef CONFIG_NUMA
+static int khugepaged_find_target_node(void)
+{
+ static int last_khugepaged_target_node = NUMA_NO_NODE;
+ int nid, target_node = 0, max_value = 0;
+
+ /* find first node with max normal pages hit */
+ for (nid = 0; nid < MAX_NUMNODES; nid++)
+ if (khugepaged_node_load[nid] > max_value) {
+ max_value = khugepaged_node_load[nid];
+ target_node = nid;
+ }
+
+ /* do some balance if several nodes have the same hit record */
+ if (target_node <= last_khugepaged_target_node)
+ for (nid = last_khugepaged_target_node + 1; nid < MAX_NUMNODES;
+ nid++)
+ if (max_value == khugepaged_node_load[nid]) {
+ target_node = nid;
+ break;
+ }
+
+ last_khugepaged_target_node = target_node;
+ return target_node;
+}
+
static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
{
if (IS_ERR(*hpage)) {
@@ -2199,9 +2252,8 @@ static struct page
* mmap_sem in read mode is good idea also to allow greater
* scalability.
*/
- *hpage = alloc_hugepage_vma(khugepaged_defrag(), vma, address,
- node, __GFP_OTHER_NODE);
-
+ *hpage = alloc_pages_exact_node(node, alloc_hugepage_gfpmask(
+ khugepaged_defrag(), __GFP_OTHER_NODE), HPAGE_PMD_ORDER);
/*
* After allocating the hugepage, release the mmap_sem read lock in
* preparation for taking it in write mode.
@@ -2217,6 +2269,17 @@ static struct page
return *hpage;
}
#else
+static int khugepaged_find_target_node(void)
+{
+ return 0;
+}
+
+static inline struct page *alloc_hugepage(int defrag)
+{
+ return alloc_pages(alloc_hugepage_gfpmask(defrag, 0),
+ HPAGE_PMD_ORDER);
+}
+
static struct page *khugepaged_alloc_hugepage(bool *wait)
{
struct page *hpage;
@@ -2423,6 +2486,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
if (pmd_trans_huge(*pmd))
goto out;
+ memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load));
pte = pte_offset_map_lock(mm, pmd, address, &ptl);
for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR;
_pte++, _address += PAGE_SIZE) {
@@ -2439,12 +2503,13 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
if (unlikely(!page))
goto out_unmap;
/*
- * Chose the node of the first page. This could
- * be more sophisticated and look at more pages,
- * but isn't for now.
+ * Record which node the original page is from and save this
+ * information to khugepaged_node_load[].
+ * Khupaged will allocate hugepage from the node has the max
+ * hit record.
*/
- if (node == NUMA_NO_NODE)
- node = page_to_nid(page);
+ node = page_to_nid(page);
+ khugepaged_node_load[node]++;
VM_BUG_ON(PageCompound(page));
if (!PageLRU(page) || PageLocked(page) || !PageAnon(page))
goto out_unmap;
@@ -2459,9 +2524,11 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
ret = 1;
out_unmap:
pte_unmap_unlock(pte, ptl);
- if (ret)
+ if (ret) {
+ node = khugepaged_find_target_node();
/* collapse_huge_page will return with the mmap_sem released */
collapse_huge_page(mm, address, hpage, vma, node);
+ }
out:
return ret;
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-03-22 15:29:06 +0000