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Commit 58730ab6 authored by Qi Zheng's avatar Qi Zheng Committed by Andrew Morton
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ksm: convert to use common struct mm_slot 

Convert to use common struct mm_slot, no functional change.

Link: https://lkml.kernel.org/r/20220831031951.43152-8-zhengqi.arch@bytedance.comSigned-off-by: default avatarQi Zheng <zhengqi.arch@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 79b09941
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Showing with 56 additions and 76 deletions
mm/ksm.c
View file @ 58730ab6
......@@ -42,6 +42,7 @@
#include <asm/tlbflush.h>
#include "internal.h"
#include "mm_slot.h"
#ifdef CONFIG_NUMA
#define NUMA(x) (x)
......@@ -113,16 +114,12 @@
/**
* struct ksm_mm_slot - ksm information per mm that is being scanned
* @hash: link to the mm_slots hash list
* @mm_node: link into the mm_slots list, rooted in ksm_mm_head
* @slot: hash lookup from mm to mm_slot
* @rmap_list: head for this mm_slot's singly-linked list of rmap_items
* @mm: the mm that this information is valid for
*/
struct ksm_mm_slot {
struct hlist_node hash;
struct list_head mm_node;
struct mm_slot slot;
struct ksm_rmap_item *rmap_list;
struct mm_struct *mm;
};
/**
......@@ -231,7 +228,7 @@ static LIST_HEAD(migrate_nodes);
static DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
static struct ksm_mm_slot ksm_mm_head = {
.mm_node = LIST_HEAD_INIT(ksm_mm_head.mm_node),
.slot.mm_node = LIST_HEAD_INIT(ksm_mm_head.slot.mm_node),
};
static struct ksm_scan ksm_scan = {
.mm_slot = &ksm_mm_head,
......@@ -409,36 +406,6 @@ static inline void free_stable_node(struct ksm_stable_node *stable_node)
kmem_cache_free(stable_node_cache, stable_node);
}
static inline struct ksm_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 ksm_mm_slot *mm_slot)
{
kmem_cache_free(mm_slot_cache, mm_slot);
}
static struct ksm_mm_slot *get_mm_slot(struct mm_struct *mm)
{
struct ksm_mm_slot *slot;
hash_for_each_possible(mm_slots_hash, slot, hash, (unsigned long)mm)
if (slot->mm == mm)
return slot;
return NULL;
}
static void insert_to_mm_slots_hash(struct mm_struct *mm,
struct ksm_mm_slot *mm_slot)
{
mm_slot->mm = mm;
hash_add(mm_slots_hash, &mm_slot->hash, (unsigned long)mm);
}
/*
* ksmd, and unmerge_and_remove_all_rmap_items(), must not touch an mm's
* page tables after it has passed through ksm_exit() - which, if necessary,
......@@ -976,20 +943,22 @@ static int remove_all_stable_nodes(void)
static int unmerge_and_remove_all_rmap_items(void)
{
struct ksm_mm_slot *mm_slot;
struct mm_slot *slot;
struct mm_struct *mm;
struct vm_area_struct *vma;
int err = 0;
spin_lock(&ksm_mmlist_lock);
ksm_scan.mm_slot = list_entry(ksm_mm_head.mm_node.next,
struct ksm_mm_slot, mm_node);
slot = list_entry(ksm_mm_head.slot.mm_node.next,
struct mm_slot, mm_node);
ksm_scan.mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot);
spin_unlock(&ksm_mmlist_lock);
for (mm_slot = ksm_scan.mm_slot; mm_slot != &ksm_mm_head;
mm_slot = ksm_scan.mm_slot) {
VMA_ITERATOR(vmi, mm_slot->mm, 0);
VMA_ITERATOR(vmi, mm_slot->slot.mm, 0);
mm = mm_slot->mm;
mm = mm_slot->slot.mm;
mmap_read_lock(mm);
for_each_vma(vmi, vma) {
if (ksm_test_exit(mm))
......@@ -1006,14 +975,15 @@ static int unmerge_and_remove_all_rmap_items(void)
mmap_read_unlock(mm);
spin_lock(&ksm_mmlist_lock);
ksm_scan.mm_slot = list_entry(mm_slot->mm_node.next,
struct ksm_mm_slot, mm_node);
slot = list_entry(mm_slot->slot.mm_node.next,
struct mm_slot, mm_node);
ksm_scan.mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot);
if (ksm_test_exit(mm)) {
hash_del(&mm_slot->hash);
list_del(&mm_slot->mm_node);
hash_del(&mm_slot->slot.hash);
list_del(&mm_slot->slot.mm_node);
spin_unlock(&ksm_mmlist_lock);
free_mm_slot(mm_slot);
mm_slot_free(mm_slot_cache, mm_slot);
clear_bit(MMF_VM_MERGEABLE, &mm->flags);
mmdrop(mm);
} else
......@@ -2235,7 +2205,7 @@ static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot,
rmap_item = alloc_rmap_item();
if (rmap_item) {
/* It has already been zeroed */
rmap_item->mm = mm_slot->mm;
rmap_item->mm = mm_slot->slot.mm;
rmap_item->mm->ksm_rmap_items++;
rmap_item->address = addr;
rmap_item->rmap_list = *rmap_list;
......@@ -2247,17 +2217,18 @@ static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot,
static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
{
struct mm_struct *mm;
struct ksm_mm_slot *slot;
struct ksm_mm_slot *mm_slot;
struct mm_slot *slot;
struct vm_area_struct *vma;
struct ksm_rmap_item *rmap_item;
struct vma_iterator vmi;
int nid;
if (list_empty(&ksm_mm_head.mm_node))
if (list_empty(&ksm_mm_head.slot.mm_node))
return NULL;
slot = ksm_scan.mm_slot;
if (slot == &ksm_mm_head) {
mm_slot = ksm_scan.mm_slot;
if (mm_slot == &ksm_mm_head) {
/*
* A number of pages can hang around indefinitely on per-cpu
* pagevecs, raised page count preventing write_protect_page
......@@ -2294,20 +2265,23 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
root_unstable_tree[nid] = RB_ROOT;
spin_lock(&ksm_mmlist_lock);
slot = list_entry(slot->mm_node.next, struct ksm_mm_slot, mm_node);
ksm_scan.mm_slot = slot;
slot = list_entry(mm_slot->slot.mm_node.next,
struct mm_slot, mm_node);
mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot);
ksm_scan.mm_slot = mm_slot;
spin_unlock(&ksm_mmlist_lock);
/*
* Although we tested list_empty() above, a racing __ksm_exit
* of the last mm on the list may have removed it since then.
*/
if (slot == &ksm_mm_head)
if (mm_slot == &ksm_mm_head)
return NULL;
next_mm:
ksm_scan.address = 0;
ksm_scan.rmap_list = &slot->rmap_list;
ksm_scan.rmap_list = &mm_slot->rmap_list;
}
slot = &mm_slot->slot;
mm = slot->mm;
vma_iter_init(&vmi, mm, ksm_scan.address);
......@@ -2337,7 +2311,7 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
if (PageAnon(*page)) {
flush_anon_page(vma, *page, ksm_scan.address);
flush_dcache_page(*page);
rmap_item = get_next_rmap_item(slot,
rmap_item = get_next_rmap_item(mm_slot,
ksm_scan.rmap_list, ksm_scan.address);
if (rmap_item) {
ksm_scan.rmap_list =
......@@ -2358,7 +2332,7 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
if (ksm_test_exit(mm)) {
no_vmas:
ksm_scan.address = 0;
ksm_scan.rmap_list = &slot->rmap_list;
ksm_scan.rmap_list = &mm_slot->rmap_list;
}
/*
* Nuke all the rmap_items that are above this current rmap:
......@@ -2367,8 +2341,9 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
remove_trailing_rmap_items(ksm_scan.rmap_list);
spin_lock(&ksm_mmlist_lock);
ksm_scan.mm_slot = list_entry(slot->mm_node.next,
struct ksm_mm_slot, mm_node);
slot = list_entry(mm_slot->slot.mm_node.next,
struct mm_slot, mm_node);
ksm_scan.mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot);
if (ksm_scan.address == 0) {
/*
* We've completed a full scan of all vmas, holding mmap_lock
......@@ -2379,11 +2354,11 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
* or when all VM_MERGEABLE areas have been unmapped (and
* mmap_lock then protects against race with MADV_MERGEABLE).
*/
hash_del(&slot->hash);
list_del(&slot->mm_node);
hash_del(&mm_slot->slot.hash);
list_del(&mm_slot->slot.mm_node);
spin_unlock(&ksm_mmlist_lock);
free_mm_slot(slot);
mm_slot_free(mm_slot_cache, mm_slot);
clear_bit(MMF_VM_MERGEABLE, &mm->flags);
mmap_read_unlock(mm);
mmdrop(mm);
......@@ -2400,8 +2375,8 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page)
}
/* Repeat until we've completed scanning the whole list */
slot = ksm_scan.mm_slot;
if (slot != &ksm_mm_head)
mm_slot = ksm_scan.mm_slot;
if (mm_slot != &ksm_mm_head)
goto next_mm;
ksm_scan.seqnr++;
......@@ -2429,7 +2404,7 @@ static void ksm_do_scan(unsigned int scan_npages)
static int ksmd_should_run(void)
{
return (ksm_run & KSM_RUN_MERGE) && !list_empty(&ksm_mm_head.mm_node);
return (ksm_run & KSM_RUN_MERGE) && !list_empty(&ksm_mm_head.slot.mm_node);
}
static int ksm_scan_thread(void *nothing)
......@@ -2519,17 +2494,20 @@ EXPORT_SYMBOL_GPL(ksm_madvise);
int __ksm_enter(struct mm_struct *mm)
{
struct ksm_mm_slot *mm_slot;
struct mm_slot *slot;
int needs_wakeup;
mm_slot = alloc_mm_slot();
mm_slot = mm_slot_alloc(mm_slot_cache);
if (!mm_slot)
return -ENOMEM;
slot = &mm_slot->slot;
/* Check ksm_run too? Would need tighter locking */
needs_wakeup = list_empty(&ksm_mm_head.mm_node);
needs_wakeup = list_empty(&ksm_mm_head.slot.mm_node);
spin_lock(&ksm_mmlist_lock);
insert_to_mm_slots_hash(mm, mm_slot);
mm_slot_insert(mm_slots_hash, mm, slot);
/*
* When KSM_RUN_MERGE (or KSM_RUN_STOP),
* insert just behind the scanning cursor, to let the area settle
......@@ -2541,9 +2519,9 @@ int __ksm_enter(struct mm_struct *mm)
* missed: then we might as well insert at the end of the list.
*/
if (ksm_run & KSM_RUN_UNMERGE)
list_add_tail(&mm_slot->mm_node, &ksm_mm_head.mm_node);
list_add_tail(&slot->mm_node, &ksm_mm_head.slot.mm_node);
else
list_add_tail(&mm_slot->mm_node, &ksm_scan.mm_slot->mm_node);
list_add_tail(&slot->mm_node, &ksm_scan.mm_slot->slot.mm_node);
spin_unlock(&ksm_mmlist_lock);
set_bit(MMF_VM_MERGEABLE, &mm->flags);
......@@ -2558,6 +2536,7 @@ int __ksm_enter(struct mm_struct *mm)
void __ksm_exit(struct mm_struct *mm)
{
struct ksm_mm_slot *mm_slot;
struct mm_slot *slot;
int easy_to_free = 0;
/*
......@@ -2570,21 +2549,22 @@ void __ksm_exit(struct mm_struct *mm)
*/
spin_lock(&ksm_mmlist_lock);
mm_slot = get_mm_slot(mm);
slot = mm_slot_lookup(mm_slots_hash, mm);
mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot);
if (mm_slot && ksm_scan.mm_slot != mm_slot) {
if (!mm_slot->rmap_list) {
hash_del(&mm_slot->hash);
list_del(&mm_slot->mm_node);
hash_del(&slot->hash);
list_del(&slot->mm_node);
easy_to_free = 1;
} else {
list_move(&mm_slot->mm_node,
&ksm_scan.mm_slot->mm_node);
list_move(&slot->mm_node,
&ksm_scan.mm_slot->slot.mm_node);
}
}
spin_unlock(&ksm_mmlist_lock);
if (easy_to_free) {
free_mm_slot(mm_slot);
mm_slot_free(mm_slot_cache, mm_slot);
clear_bit(MMF_VM_MERGEABLE, &mm->flags);
mmdrop(mm);
} else if (mm_slot) {
......
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