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Subject[PATCH v2 2/7] mm: thp: convert to use common struct mm_slot
Date
Rename private struct mm_slot to struct khugepaged_mm_slot and
convert to use common struct mm_slot with no functional change.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
mm/khugepaged.c | 121 ++++++++++++++++++++----------------------------
1 file changed, 51 insertions(+), 70 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index d8e388106322..2d74cf01f694 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -23,6 +23,7 @@
#include <asm/tlb.h>
#include <asm/pgalloc.h>
#include "internal.h"
+#include "mm_slot.h"

enum scan_result {
SCAN_FAIL,
@@ -104,17 +105,13 @@ struct collapse_control {
};

/**
- * struct mm_slot - hash lookup from mm to mm_slot
- * @hash: hash collision list
- * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head
- * @mm: the mm that this information is valid for
+ * struct khugepaged_mm_slot - khugepaged information per mm that is being scanned
+ * @slot: hash lookup from mm to mm_slot
* @nr_pte_mapped_thp: number of pte mapped THP
* @pte_mapped_thp: address array corresponding pte mapped THP
*/
-struct mm_slot {
- struct hlist_node hash;
- struct list_head mm_node;
- struct mm_struct *mm;
+struct khugepaged_mm_slot {
+ struct mm_slot slot;

/* pte-mapped THP in this mm */
int nr_pte_mapped_thp;
@@ -131,7 +128,7 @@ struct mm_slot {
*/
struct khugepaged_scan {
struct list_head mm_head;
- struct mm_slot *mm_slot;
+ struct khugepaged_mm_slot *mm_slot;
unsigned long address;
};

@@ -395,8 +392,9 @@ int hugepage_madvise(struct vm_area_struct *vma,
int __init khugepaged_init(void)
{
mm_slot_cache = kmem_cache_create("khugepaged_mm_slot",
- sizeof(struct mm_slot),
- __alignof__(struct mm_slot), 0, NULL);
+ sizeof(struct khugepaged_mm_slot),
+ __alignof__(struct khugepaged_mm_slot),
+ 0, NULL);
if (!mm_slot_cache)
return -ENOMEM;

@@ -413,36 +411,6 @@ void __init khugepaged_destroy(void)
kmem_cache_destroy(mm_slot_cache);
}

-static inline struct mm_slot *alloc_mm_slot(void)
-{
- if (!mm_slot_cache) /* initialization failed */
- return NULL;
- return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL);
-}
-
-static inline void free_mm_slot(struct mm_slot *mm_slot)
-{
- kmem_cache_free(mm_slot_cache, mm_slot);
-}
-
-static struct mm_slot *get_mm_slot(struct mm_struct *mm)
-{
- struct mm_slot *mm_slot;
-
- hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm)
- if (mm == mm_slot->mm)
- return mm_slot;
-
- return NULL;
-}
-
-static void insert_to_mm_slots_hash(struct mm_struct *mm,
- struct mm_slot *mm_slot)
-{
- mm_slot->mm = mm;
- hash_add(mm_slots_hash, &mm_slot->hash, (long)mm);
-}
-
static inline int hpage_collapse_test_exit(struct mm_struct *mm)
{
return atomic_read(&mm->mm_users) == 0;
@@ -450,28 +418,31 @@ static inline int hpage_collapse_test_exit(struct mm_struct *mm)

void __khugepaged_enter(struct mm_struct *mm)
{
- struct mm_slot *mm_slot;
+ struct khugepaged_mm_slot *mm_slot;
+ struct mm_slot *slot;
int wakeup;

- mm_slot = alloc_mm_slot();
+ mm_slot = mm_slot_alloc(mm_slot_cache);
if (!mm_slot)
return;

+ slot = &mm_slot->slot;
+
/* __khugepaged_exit() must not run from under us */
VM_BUG_ON_MM(hpage_collapse_test_exit(mm), mm);
if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) {
- free_mm_slot(mm_slot);
+ mm_slot_free(mm_slot_cache, mm_slot);
return;
}

spin_lock(&khugepaged_mm_lock);
- insert_to_mm_slots_hash(mm, mm_slot);
+ mm_slot_insert(mm_slots_hash, mm, slot);
/*
* Insert just behind the scanning cursor, to let the area settle
* down a little.
*/
wakeup = list_empty(&khugepaged_scan.mm_head);
- list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head);
+ list_add_tail(&slot->mm_node, &khugepaged_scan.mm_head);
spin_unlock(&khugepaged_mm_lock);

mmgrab(mm);
@@ -491,21 +462,23 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,

void __khugepaged_exit(struct mm_struct *mm)
{
- struct mm_slot *mm_slot;
+ struct khugepaged_mm_slot *mm_slot;
+ struct mm_slot *slot;
int free = 0;

spin_lock(&khugepaged_mm_lock);
- mm_slot = get_mm_slot(mm);
+ slot = mm_slot_lookup(mm_slots_hash, mm);
+ mm_slot = mm_slot_entry(slot, struct khugepaged_mm_slot, slot);
if (mm_slot && khugepaged_scan.mm_slot != mm_slot) {
- hash_del(&mm_slot->hash);
- list_del(&mm_slot->mm_node);
+ hash_del(&slot->hash);
+ list_del(&slot->mm_node);
free = 1;
}
spin_unlock(&khugepaged_mm_lock);

if (free) {
clear_bit(MMF_VM_HUGEPAGE, &mm->flags);
- free_mm_slot(mm_slot);
+ mm_slot_free(mm_slot_cache, mm_slot);
mmdrop(mm);
} else if (mm_slot) {
/*
@@ -1321,16 +1294,17 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
return result;
}

-static void collect_mm_slot(struct mm_slot *mm_slot)
+static void collect_mm_slot(struct khugepaged_mm_slot *mm_slot)
{
- struct mm_struct *mm = mm_slot->mm;
+ struct mm_slot *slot = &mm_slot->slot;
+ struct mm_struct *mm = slot->mm;

lockdep_assert_held(&khugepaged_mm_lock);

if (hpage_collapse_test_exit(mm)) {
/* free mm_slot */
- hash_del(&mm_slot->hash);
- list_del(&mm_slot->mm_node);
+ hash_del(&slot->hash);
+ list_del(&slot->mm_node);

/*
* Not strictly needed because the mm exited already.
@@ -1339,7 +1313,7 @@ static void collect_mm_slot(struct mm_slot *mm_slot)
*/

/* khugepaged_mm_lock actually not necessary for the below */
- free_mm_slot(mm_slot);
+ mm_slot_free(mm_slot_cache, mm_slot);
mmdrop(mm);
}
}
@@ -1352,12 +1326,14 @@ static void collect_mm_slot(struct mm_slot *mm_slot)
static void khugepaged_add_pte_mapped_thp(struct mm_struct *mm,
unsigned long addr)
{
- struct mm_slot *mm_slot;
+ struct khugepaged_mm_slot *mm_slot;
+ struct mm_slot *slot;

VM_BUG_ON(addr & ~HPAGE_PMD_MASK);

spin_lock(&khugepaged_mm_lock);
- mm_slot = get_mm_slot(mm);
+ slot = mm_slot_lookup(mm_slots_hash, mm);
+ mm_slot = mm_slot_entry(slot, struct khugepaged_mm_slot, slot);
if (likely(mm_slot && mm_slot->nr_pte_mapped_thp < MAX_PTE_MAPPED_THP))
mm_slot->pte_mapped_thp[mm_slot->nr_pte_mapped_thp++] = addr;
spin_unlock(&khugepaged_mm_lock);
@@ -1489,9 +1465,10 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
goto drop_hpage;
}

-static void khugepaged_collapse_pte_mapped_thps(struct mm_slot *mm_slot)
+static void khugepaged_collapse_pte_mapped_thps(struct khugepaged_mm_slot *mm_slot)
{
- struct mm_struct *mm = mm_slot->mm;
+ struct mm_slot *slot = &mm_slot->slot;
+ struct mm_struct *mm = slot->mm;
int i;

if (likely(mm_slot->nr_pte_mapped_thp == 0))
@@ -2054,7 +2031,8 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
__acquires(&khugepaged_mm_lock)
{
struct vma_iterator vmi;
- struct mm_slot *mm_slot;
+ struct khugepaged_mm_slot *mm_slot;
+ struct mm_slot *slot;
struct mm_struct *mm;
struct vm_area_struct *vma;
int progress = 0;
@@ -2064,18 +2042,20 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
lockdep_assert_held(&khugepaged_mm_lock);
*result = SCAN_FAIL;

- if (khugepaged_scan.mm_slot)
+ if (khugepaged_scan.mm_slot) {
mm_slot = khugepaged_scan.mm_slot;
- else {
- mm_slot = list_entry(khugepaged_scan.mm_head.next,
+ slot = &mm_slot->slot;
+ } else {
+ slot = list_entry(khugepaged_scan.mm_head.next,
struct mm_slot, mm_node);
+ mm_slot = mm_slot_entry(slot, struct khugepaged_mm_slot, slot);
khugepaged_scan.address = 0;
khugepaged_scan.mm_slot = mm_slot;
}
spin_unlock(&khugepaged_mm_lock);
khugepaged_collapse_pte_mapped_thps(mm_slot);

- mm = mm_slot->mm;
+ mm = slot->mm;
/*
* Don't wait for semaphore (to avoid long wait times). Just move to
* the next mm on the list.
@@ -2171,10 +2151,11 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
* khugepaged runs here, khugepaged_exit will find
* mm_slot not pointing to the exiting mm.
*/
- if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) {
- khugepaged_scan.mm_slot = list_entry(
- mm_slot->mm_node.next,
- struct mm_slot, mm_node);
+ if (slot->mm_node.next != &khugepaged_scan.mm_head) {
+ slot = list_entry(slot->mm_node.next,
+ struct mm_slot, mm_node);
+ khugepaged_scan.mm_slot =
+ mm_slot_entry(slot, struct khugepaged_mm_slot, slot);
khugepaged_scan.address = 0;
} else {
khugepaged_scan.mm_slot = NULL;
@@ -2269,7 +2250,7 @@ static void khugepaged_wait_work(void)

static int khugepaged(void *none)
{
- struct mm_slot *mm_slot;
+ struct khugepaged_mm_slot *mm_slot;

set_freezable();
set_user_nice(current, MAX_NICE);
--
2.20.1
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