The following code is duplicated in collapse_huge_page() and
collapse_file():
/* Only allocate from the target node */
gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE;
new_page = khugepaged_alloc_page(hpage, gfp, node);
if (!new_page) {
result = SCAN_ALLOC_HUGE_PAGE_FAIL;
goto out;
}
if (unlikely(mem_cgroup_charge(page_folio(new_page), mm, gfp))) {
result = SCAN_CGROUP_CHARGE_FAIL;
goto out;
}
count_memcg_page_event(new_page, THP_COLLAPSE_ALLOC);
Also, "node" is passed as an argument to both collapse_huge_page() and
collapse_file() and obtained the same way, via
khugepaged_find_target_node().
Move all this into a new helper, alloc_charge_hpage(), and remove the
duplicate code from collapse_huge_page() and collapse_file(). Also,
simplify khugepaged_alloc_page() by returning a bool indicating
allocation success instead of a copy of the (possibly) allocated
struct page.
Suggested-by: Peter Xu <peterx@xxxxxxxxxx>
Signed-off-by: Zach O'Keefe <zokeefe@xxxxxxxxxx>
---
This patch currently depends on 'mm/khugepaged: sched to numa node when
collapse huge page' currently being discussed upstream[1], and
anticipates that this functionality would be equally applicable to
file-backed collapse. It also goes ahead and wraps this code in a
CONFIF_NUMA #ifdef.
[1] https://lore.kernel.org/linux-mm/20220317065024.2635069-1-maobibo@xxxxxxxxxxx/
mm/khugepaged.c | 99 +++++++++++++++++++++++--------------------------
1 file changed, 46 insertions(+), 53 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index d3cb670921cd..c94bc43dff3e 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -866,8 +866,7 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
return true;
}
-static struct page *
-khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)
+static bool khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)
{
VM_BUG_ON_PAGE(*hpage, *hpage);
@@ -875,12 +874,12 @@ khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)
if (unlikely(!*hpage)) {
count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
*hpage = ERR_PTR(-ENOMEM);
- return NULL;
+ return false;
}
prep_transhuge_page(*hpage);
count_vm_event(THP_COLLAPSE_ALLOC);
- return *hpage;
+ return true;
}
#else
static int khugepaged_find_target_node(struct collapse_control *cc)
@@ -942,12 +941,11 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
return true;
}
-static struct page *
-khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)
+static bool khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)
{
VM_BUG_ON(!*hpage);
- return *hpage;
+ return true;
}
#endif
@@ -1069,10 +1067,34 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm,
return true;
}
-static void collapse_huge_page(struct mm_struct *mm,
- unsigned long address,
- struct page **hpage,
- int node, int referenced, int unmapped)
+static int alloc_charge_hpage(struct page **hpage, struct mm_struct *mm,
+ struct collapse_control *cc)
+{
+#ifdef CONFIG_NUMA
+ const struct cpumask *cpumask;
+#endif
+ gfp_t gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE;
+ int node = khugepaged_find_target_node(cc);
+
+#ifdef CONFIG_NUMA
+ /* sched to specified node before huge page memory copy */
+ if (task_node(current) != node) {
+ cpumask = cpumask_of_node(node);
+ if (!cpumask_empty(cpumask))
+ set_cpus_allowed_ptr(current, cpumask);
+ }
+#endif
+ if (!khugepaged_alloc_page(hpage, gfp, node))
+ return SCAN_ALLOC_HUGE_PAGE_FAIL;
+ if (unlikely(mem_cgroup_charge(page_folio(*hpage), mm, gfp)))
+ return SCAN_CGROUP_CHARGE_FAIL;
+ count_memcg_page_event(*hpage, THP_COLLAPSE_ALLOC);
+ return SCAN_SUCCEED;
+}
+
+static void collapse_huge_page(struct mm_struct *mm, unsigned long address,
+ struct page **hpage, int referenced,
+ int unmapped, struct collapse_control *cc)
{
LIST_HEAD(compound_pagelist);
pmd_t *pmd, _pmd;
@@ -1083,14 +1105,9 @@ static void collapse_huge_page(struct mm_struct *mm,
int isolated = 0, result = 0;
struct vm_area_struct *vma;
struct mmu_notifier_range range;
- gfp_t gfp;
- const struct cpumask *cpumask;
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
- /* Only allocate from the target node */
- gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE;
-
/*
* Before allocating the hugepage, release the mmap_lock read lock.
* The allocation can take potentially a long time if it involves
@@ -1099,23 +1116,11 @@ static void collapse_huge_page(struct mm_struct *mm,
*/
mmap_read_unlock(mm);
- /* sched to specified node before huage page memory copy */
- if (task_node(current) != node) {
- cpumask = cpumask_of_node(node);
- if (!cpumask_empty(cpumask))
- set_cpus_allowed_ptr(current, cpumask);
- }
- new_page = khugepaged_alloc_page(hpage, gfp, node);
- if (!new_page) {
- result = SCAN_ALLOC_HUGE_PAGE_FAIL;
+ result = alloc_charge_hpage(hpage, mm, cc);
+ if (result != SCAN_SUCCEED)
goto out_nolock;
- }
- if (unlikely(mem_cgroup_charge(page_folio(new_page), mm, gfp))) {
- result = SCAN_CGROUP_CHARGE_FAIL;
- goto out_nolock;
- }
- count_memcg_page_event(new_page, THP_COLLAPSE_ALLOC);
+ new_page = *hpage;
mmap_read_lock(mm);
result = hugepage_vma_revalidate(mm, address, &vma);
@@ -1386,10 +1391,9 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
out_unmap:
pte_unmap_unlock(pte, ptl);
if (ret) {
- node = khugepaged_find_target_node(cc);
/* collapse_huge_page will return with the mmap_lock released */
- collapse_huge_page(mm, address, hpage, node,
- referenced, unmapped);
+ collapse_huge_page(mm, address, hpage, referenced, unmapped,
+ cc);
}
out:
trace_mm_khugepaged_scan_pmd(mm, page, writable, referenced,
@@ -1655,7 +1659,7 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
* @file: file that collapse on
* @start: collapse start address
* @hpage: new allocated huge page for collapse
- * @node: appointed node the new huge page allocate from
+ * @cc: collapse context and scratchpad
*
* Basic scheme is simple, details are more complex:
* - allocate and lock a new huge page;
@@ -1672,12 +1676,11 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
* + restore gaps in the page cache;
* + unlock and free huge page;
*/
-static void collapse_file(struct mm_struct *mm,
- struct file *file, pgoff_t start,
- struct page **hpage, int node)
+static void collapse_file(struct mm_struct *mm, struct file *file,
+ pgoff_t start, struct page **hpage,
+ struct collapse_control *cc)
{
struct address_space *mapping = file->f_mapping;
- gfp_t gfp;
struct page *new_page;
pgoff_t index, end = start + HPAGE_PMD_NR;
LIST_HEAD(pagelist);
@@ -1689,20 +1692,11 @@ static void collapse_file(struct mm_struct *mm,
VM_BUG_ON(!IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && !is_shmem);
VM_BUG_ON(start & (HPAGE_PMD_NR - 1));
- /* Only allocate from the target node */
- gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE;
-
- new_page = khugepaged_alloc_page(hpage, gfp, node);
- if (!new_page) {
- result = SCAN_ALLOC_HUGE_PAGE_FAIL;
+ result = alloc_charge_hpage(hpage, mm, cc);
+ if (result != SCAN_SUCCEED)
goto out;
- }
- if (unlikely(mem_cgroup_charge(page_folio(new_page), mm, gfp))) {
- result = SCAN_CGROUP_CHARGE_FAIL;
- goto out;
- }
- count_memcg_page_event(new_page, THP_COLLAPSE_ALLOC);
+ new_page = *hpage;
/*
* Ensure we have slots for all the pages in the range. This is
@@ -2112,8 +2106,7 @@ static void khugepaged_scan_file(struct mm_struct *mm, struct file *file,
result = SCAN_EXCEED_NONE_PTE;
count_vm_event(THP_SCAN_EXCEED_NONE_PTE);
} else {
- node = khugepaged_find_target_node(cc);
- collapse_file(mm, file, start, hpage, node);
+ collapse_file(mm, file, start, hpage, cc);
}
}
--
2.36.0.464.gb9c8b46e94-goog
