* [PATCH v5 2/8] mm/lru: replace pgdat lru_lock with lruvec lock
2019-12-10 11:46 [PATCH v5 0/8] per lruvec lru_lock for memcg Alex Shi
2019-12-10 11:46 ` [PATCH v5 1/8] mm/vmscan: remove unnecessary lruvec adding Alex Shi
@ 2019-12-10 11:46 ` Alex Shi
2019-12-10 13:41 ` Matthew Wilcox
2019-12-10 11:46 ` [PATCH v5 3/8] mm/lru: introduce the relock_page_lruvec function Alex Shi
` (5 subsequent siblings)
7 siblings, 1 reply; 11+ messages in thread
From: Alex Shi @ 2019-12-10 11:46 UTC (permalink / raw)
To: cgroups, linux-kernel, linux-mm, akpm, mgorman, tj, hughd,
khlebnikov, daniel.m.jordan, yang.shi, willy, shakeelb, hannes
Cc: Alex Shi, Michal Hocko, Vladimir Davydov, Roman Gushchin,
Chris Down, Thomas Gleixner, Vlastimil Babka, Qian Cai,
Andrey Ryabinin, Kirill A. Shutemov, Jérôme Glisse,
Andrea Arcangeli, David Rientjes, Aneesh Kumar K.V, swkhack,
Potyra, Stefan, Mike Rapoport, Stephen Rothwell, Colin Ian King,
Jason Gunthorpe, Mauro Carvalho Chehab, Peng Fan,
Nikolay Borisov, Ira Weiny, Kirill Tkhai, Yafang Shao
This patchset move lru_lock into lruvec, give a lru_lock for each of
lruvec, thus bring a lru_lock for each of memcg per node.
This is the main patch to replace per node lru_lock with per memcg
lruvec lock.
We introduces function lock_page_lruvec, which will lock the page's
memcg and then memcg's lruvec->lru_lock. (Thanks Johannes Weiner,
Hugh Dickins and Konstantin Khlebnikov suggestion/reminder on them)
According to Daniel Jordan's suggestion, I run 208 'dd' with on 104
containers on a 2s * 26cores * HT box with a modefied case:
https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/tree/case-lru-file-readtwice
With this and later patches, the readtwice performance increases about
80% with containers, but w/o memcg the readtwice performance drops
about 5%.(and another 5% drops with the last debug patch).
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Chris Down <chris@chrisdown.name>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Qian Cai <cai@lca.pw>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: swkhack <swkhack@gmail.com>
Cc: "Potyra, Stefan" <Stefan.Potyra@elektrobit.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Nikolay Borisov <nborisov@suse.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: cgroups@vger.kernel.org
---
include/linux/memcontrol.h | 27 ++++++++++++++++
include/linux/mmzone.h | 2 ++
mm/compaction.c | 55 +++++++++++++++++++++-----------
mm/huge_memory.c | 18 ++++-------
mm/memcontrol.c | 75 ++++++++++++++++++++++++++++++++-----------
mm/mlock.c | 32 +++++++++----------
mm/mmzone.c | 1 +
mm/page_idle.c | 7 ++--
mm/swap.c | 75 ++++++++++++++++++-------------------------
mm/vmscan.c | 79 ++++++++++++++++++++++++++--------------------
10 files changed, 221 insertions(+), 150 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 5b86287fa069..16449d9836ee 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -417,6 +417,10 @@ static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
}
struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *);
+struct lruvec *lock_page_lruvec_irq(struct page *);
+struct lruvec *lock_page_lruvec_irqsave(struct page *, unsigned long*);
+void unlock_page_lruvec_irq(struct lruvec *);
+void unlock_page_lruvec_irqrestore(struct lruvec *, unsigned long);
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
@@ -900,6 +904,29 @@ static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
{
return &pgdat->__lruvec;
}
+#define lock_page_lruvec_irq(page) \
+({ \
+ struct pglist_data *pgdat = page_pgdat(page); \
+ spin_lock_irq(&pgdat->__lruvec.lru_lock); \
+ &pgdat->__lruvec; \
+})
+
+#define lock_page_lruvec_irqsave(page, flagsp) \
+({ \
+ struct pglist_data *pgdat = page_pgdat(page); \
+ spin_lock_irqsave(&pgdat->__lruvec.lru_lock, *flagsp); \
+ &pgdat->__lruvec; \
+})
+
+#define unlock_page_lruvec_irq(lruvec) \
+({ \
+ spin_unlock_irq(&lruvec->lru_lock); \
+})
+
+#define unlock_page_lruvec_irqrestore(lruvec, flags) \
+({ \
+ spin_unlock_irqrestore(&lruvec->lru_lock, flags); \
+})
static inline bool mm_match_cgroup(struct mm_struct *mm,
struct mem_cgroup *memcg)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 07b784ffbb14..a13b8a602ee5 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -267,6 +267,8 @@ struct lruvec {
unsigned long refaults;
/* Various lruvec state flags (enum lruvec_flags) */
unsigned long flags;
+ /* per lruvec lru_lock for memcg */
+ spinlock_t lru_lock;
#ifdef CONFIG_MEMCG
struct pglist_data *pgdat;
#endif
diff --git a/mm/compaction.c b/mm/compaction.c
index d20816b21b55..0907eec3db84 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -787,7 +787,7 @@ static bool too_many_isolated(pg_data_t *pgdat)
unsigned long nr_scanned = 0, nr_isolated = 0;
struct lruvec *lruvec;
unsigned long flags = 0;
- bool locked = false;
+ struct lruvec *locked_lruvec = NULL;
struct page *page = NULL, *valid_page = NULL;
unsigned long start_pfn = low_pfn;
bool skip_on_failure = false;
@@ -847,11 +847,20 @@ static bool too_many_isolated(pg_data_t *pgdat)
* contention, to give chance to IRQs. Abort completely if
* a fatal signal is pending.
*/
- if (!(low_pfn % SWAP_CLUSTER_MAX)
- && compact_unlock_should_abort(&pgdat->lru_lock,
- flags, &locked, cc)) {
- low_pfn = 0;
- goto fatal_pending;
+ if (!(low_pfn % SWAP_CLUSTER_MAX)) {
+ if (locked_lruvec) {
+ unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+ locked_lruvec = NULL;
+ }
+
+ if (fatal_signal_pending(current)) {
+ cc->contended = true;
+
+ low_pfn = 0;
+ goto fatal_pending;
+ }
+
+ cond_resched();
}
if (!pfn_valid_within(low_pfn))
@@ -920,10 +929,9 @@ static bool too_many_isolated(pg_data_t *pgdat)
*/
if (unlikely(__PageMovable(page)) &&
!PageIsolated(page)) {
- if (locked) {
- spin_unlock_irqrestore(&pgdat->lru_lock,
- flags);
- locked = false;
+ if (locked_lruvec) {
+ unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+ locked_lruvec = NULL;
}
if (!isolate_movable_page(page, isolate_mode))
@@ -949,10 +957,20 @@ static bool too_many_isolated(pg_data_t *pgdat)
if (!(cc->gfp_mask & __GFP_FS) && page_mapping(page))
goto isolate_fail;
+ lruvec = mem_cgroup_page_lruvec(page, pgdat);
+
/* If we already hold the lock, we can skip some rechecking */
- if (!locked) {
- locked = compact_lock_irqsave(&pgdat->lru_lock,
- &flags, cc);
+ if (lruvec != locked_lruvec) {
+ struct mem_cgroup *memcg = lock_page_memcg(page);
+
+ if (locked_lruvec) {
+ unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+ locked_lruvec = NULL;
+ }
+ /* reget lruvec with a locked memcg */
+ lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
+ compact_lock_irqsave(&lruvec->lru_lock, &flags, cc);
+ locked_lruvec = lruvec;
/* Try get exclusive access under lock */
if (!skip_updated) {
@@ -976,7 +994,6 @@ static bool too_many_isolated(pg_data_t *pgdat)
}
}
- lruvec = mem_cgroup_page_lruvec(page, pgdat);
/* Try isolate the page */
if (__isolate_lru_page(page, isolate_mode) != 0)
@@ -1017,9 +1034,9 @@ static bool too_many_isolated(pg_data_t *pgdat)
* page anyway.
*/
if (nr_isolated) {
- if (locked) {
- spin_unlock_irqrestore(&pgdat->lru_lock, flags);
- locked = false;
+ if (locked_lruvec) {
+ unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+ locked_lruvec = NULL;
}
putback_movable_pages(&cc->migratepages);
cc->nr_migratepages = 0;
@@ -1044,8 +1061,8 @@ static bool too_many_isolated(pg_data_t *pgdat)
low_pfn = end_pfn;
isolate_abort:
- if (locked)
- spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+ if (locked_lruvec)
+ unlock_page_lruvec_irqrestore(locked_lruvec, flags);
/*
* Updated the cached scanner pfn once the pageblock has been scanned
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 13cc93785006..ea76d2998fa9 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2495,17 +2495,13 @@ static void __split_huge_page_tail(struct page *head, int tail,
}
static void __split_huge_page(struct page *page, struct list_head *list,
- pgoff_t end, unsigned long flags)
+ struct lruvec *lruvec, pgoff_t end, unsigned long flags)
{
struct page *head = compound_head(page);
- pg_data_t *pgdat = page_pgdat(head);
- struct lruvec *lruvec;
struct address_space *swap_cache = NULL;
unsigned long offset = 0;
int i;
- lruvec = mem_cgroup_page_lruvec(head, pgdat);
-
/* complete memcg works before add pages to LRU */
mem_cgroup_split_huge_fixup(head);
@@ -2554,7 +2550,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
xa_unlock(&head->mapping->i_pages);
}
- spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+ unlock_page_lruvec_irqrestore(lruvec, flags);
remap_page(head);
@@ -2693,13 +2689,13 @@ bool can_split_huge_page(struct page *page, int *pextra_pins)
int split_huge_page_to_list(struct page *page, struct list_head *list)
{
struct page *head = compound_head(page);
- struct pglist_data *pgdata = NODE_DATA(page_to_nid(head));
struct deferred_split *ds_queue = get_deferred_split_queue(page);
struct anon_vma *anon_vma = NULL;
struct address_space *mapping = NULL;
+ struct lruvec *lruvec;
int count, mapcount, extra_pins, ret;
bool mlocked;
- unsigned long flags;
+ unsigned long uninitialized_var(flags);
pgoff_t end;
VM_BUG_ON_PAGE(is_huge_zero_page(page), page);
@@ -2766,7 +2762,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
lru_add_drain();
/* prevent PageLRU to go away from under us, and freeze lru stats */
- spin_lock_irqsave(&pgdata->lru_lock, flags);
+ lruvec = lock_page_lruvec_irqsave(head, &flags);
if (mapping) {
XA_STATE(xas, &mapping->i_pages, page_index(head));
@@ -2797,7 +2793,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
}
spin_unlock(&ds_queue->split_queue_lock);
- __split_huge_page(page, list, end, flags);
+ __split_huge_page(page, list, lruvec, end, flags);
if (PageSwapCache(head)) {
swp_entry_t entry = { .val = page_private(head) };
@@ -2816,7 +2812,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
spin_unlock(&ds_queue->split_queue_lock);
fail: if (mapping)
xa_unlock(&mapping->i_pages);
- spin_unlock_irqrestore(&pgdata->lru_lock, flags);
+ unlock_page_lruvec_irqrestore(lruvec, flags);
remap_page(head);
ret = -EBUSY;
}
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 62470325f9bc..4a92689c37d6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1210,11 +1210,11 @@ int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
* @page: the page
* @pgdat: pgdat of the page
*
- * This function is only safe when following the LRU page isolation
- * and putback protocol: the LRU lock must be held, and the page must
- * either be PageLRU() or the caller must have isolated/allocated it.
+ * The caller needs to grantee the page's mem_cgroup is undisturbed during
+ * using. That could be done by lock_page_memcg or lock_page_lruvec.
*/
-struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat)
+struct lruvec *mem_cgroup_page_lruvec(struct page *page,
+ struct pglist_data *pgdat)
{
struct mem_cgroup_per_node *mz;
struct mem_cgroup *memcg;
@@ -1225,7 +1225,7 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
goto out;
}
- memcg = page->mem_cgroup;
+ memcg = READ_ONCE(page->mem_cgroup);
/*
* Swapcache readahead pages are added to the LRU - and
* possibly migrated - before they are charged.
@@ -1246,6 +1246,42 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
return lruvec;
}
+struct lruvec *lock_page_lruvec_irq(struct page *page)
+{
+ struct lruvec *lruvec;
+ struct mem_cgroup *memcg;
+
+ memcg = lock_page_memcg(page);
+ lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
+ spin_lock_irq(&lruvec->lru_lock);
+
+ return lruvec;
+}
+
+struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags)
+{
+ struct lruvec *lruvec;
+ struct mem_cgroup *memcg;
+
+ memcg = lock_page_memcg(page);
+ lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
+ spin_lock_irqsave(&lruvec->lru_lock, *flags);
+
+ return lruvec;
+}
+
+void unlock_page_lruvec_irq(struct lruvec *lruvec)
+{
+ spin_unlock_irq(&lruvec->lru_lock);
+ __unlock_page_memcg(lruvec_memcg(lruvec));
+}
+
+void unlock_page_lruvec_irqrestore(struct lruvec *lruvec, unsigned long flags)
+{
+ spin_unlock_irqrestore(&lruvec->lru_lock, flags);
+ __unlock_page_memcg(lruvec_memcg(lruvec));
+}
+
/**
* mem_cgroup_update_lru_size - account for adding or removing an lru page
* @lruvec: mem_cgroup per zone lru vector
@@ -2571,41 +2607,42 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
css_put_many(&memcg->css, nr_pages);
}
-static void lock_page_lru(struct page *page, int *isolated)
+static struct lruvec *lock_page_lru(struct page *page, int *isolated)
{
- pg_data_t *pgdat = page_pgdat(page);
+ struct lruvec *lruvec = lock_page_lruvec_irq(page);
- spin_lock_irq(&pgdat->lru_lock);
if (PageLRU(page)) {
- struct lruvec *lruvec;
- lruvec = mem_cgroup_page_lruvec(page, pgdat);
ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_lru(page));
*isolated = 1;
} else
*isolated = 0;
+
+ return lruvec;
}
-static void unlock_page_lru(struct page *page, int isolated)
+static void unlock_page_lru(struct page *page, int isolated,
+ struct lruvec *locked_lruvec)
{
- pg_data_t *pgdat = page_pgdat(page);
+ struct lruvec *lruvec;
- if (isolated) {
- struct lruvec *lruvec;
+ unlock_page_lruvec_irq(locked_lruvec);
+ lruvec = lock_page_lruvec_irq(page);
- lruvec = mem_cgroup_page_lruvec(page, pgdat);
+ if (isolated) {
VM_BUG_ON_PAGE(PageLRU(page), page);
SetPageLRU(page);
add_page_to_lru_list(page, lruvec, page_lru(page));
}
- spin_unlock_irq(&pgdat->lru_lock);
+ unlock_page_lruvec_irq(lruvec);
}
static void commit_charge(struct page *page, struct mem_cgroup *memcg,
bool lrucare)
{
int isolated;
+ struct lruvec *lruvec;
VM_BUG_ON_PAGE(page->mem_cgroup, page);
@@ -2614,7 +2651,7 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
* may already be on some other mem_cgroup's LRU. Take care of it.
*/
if (lrucare)
- lock_page_lru(page, &isolated);
+ lruvec = lock_page_lru(page, &isolated);
/*
* Nobody should be changing or seriously looking at
@@ -2633,7 +2670,7 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
page->mem_cgroup = memcg;
if (lrucare)
- unlock_page_lru(page, isolated);
+ unlock_page_lru(page, isolated, lruvec);
}
#ifdef CONFIG_MEMCG_KMEM
@@ -2929,7 +2966,7 @@ void __memcg_kmem_uncharge(struct page *page, int order)
/*
* Because tail pages are not marked as "used", set it. We're under
- * pgdat->lru_lock and migration entries setup in all page mappings.
+ * lruvec->lru_lock and migration entries setup in all page mappings.
*/
void mem_cgroup_split_huge_fixup(struct page *head)
{
diff --git a/mm/mlock.c b/mm/mlock.c
index a72c1eeded77..10d15f58b061 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -106,12 +106,10 @@ void mlock_vma_page(struct page *page)
* Isolate a page from LRU with optional get_page() pin.
* Assumes lru_lock already held and page already pinned.
*/
-static bool __munlock_isolate_lru_page(struct page *page, bool getpage)
+static bool __munlock_isolate_lru_page(struct page *page,
+ struct lruvec *lruvec, bool getpage)
{
if (PageLRU(page)) {
- struct lruvec *lruvec;
-
- lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
if (getpage)
get_page(page);
ClearPageLRU(page);
@@ -182,7 +180,7 @@ static void __munlock_isolation_failed(struct page *page)
unsigned int munlock_vma_page(struct page *page)
{
int nr_pages;
- pg_data_t *pgdat = page_pgdat(page);
+ struct lruvec *lruvec;
/* For try_to_munlock() and to serialize with page migration */
BUG_ON(!PageLocked(page));
@@ -194,7 +192,7 @@ unsigned int munlock_vma_page(struct page *page)
* might otherwise copy PageMlocked to part of the tail pages before
* we clear it in the head page. It also stabilizes hpage_nr_pages().
*/
- spin_lock_irq(&pgdat->lru_lock);
+ lruvec = lock_page_lruvec_irq(page);
if (!TestClearPageMlocked(page)) {
/* Potentially, PTE-mapped THP: do not skip the rest PTEs */
@@ -205,15 +203,15 @@ unsigned int munlock_vma_page(struct page *page)
nr_pages = hpage_nr_pages(page);
__mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
- if (__munlock_isolate_lru_page(page, true)) {
- spin_unlock_irq(&pgdat->lru_lock);
+ if (__munlock_isolate_lru_page(page, lruvec, true)) {
+ unlock_page_lruvec_irq(lruvec);
__munlock_isolated_page(page);
goto out;
}
__munlock_isolation_failed(page);
unlock_out:
- spin_unlock_irq(&pgdat->lru_lock);
+ unlock_page_lruvec_irq(lruvec);
out:
return nr_pages - 1;
@@ -291,28 +289,29 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
{
int i;
int nr = pagevec_count(pvec);
- int delta_munlocked = -nr;
struct pagevec pvec_putback;
+ struct lruvec *lruvec = NULL;
int pgrescued = 0;
pagevec_init(&pvec_putback);
/* Phase 1: page isolation */
- spin_lock_irq(&zone->zone_pgdat->lru_lock);
for (i = 0; i < nr; i++) {
struct page *page = pvec->pages[i];
+ lruvec = lock_page_lruvec_irq(page);
+
if (TestClearPageMlocked(page)) {
/*
* We already have pin from follow_page_mask()
* so we can spare the get_page() here.
*/
- if (__munlock_isolate_lru_page(page, false))
+ if (__munlock_isolate_lru_page(page, lruvec, false)) {
+ __mod_zone_page_state(zone, NR_MLOCK, -1);
+ unlock_page_lruvec_irq(lruvec);
continue;
- else
+ } else
__munlock_isolation_failed(page);
- } else {
- delta_munlocked++;
}
/*
@@ -323,9 +322,8 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
*/
pagevec_add(&pvec_putback, pvec->pages[i]);
pvec->pages[i] = NULL;
+ unlock_page_lruvec_irq(lruvec);
}
- __mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
- spin_unlock_irq(&zone->zone_pgdat->lru_lock);
/* Now we can release pins of pages that we are not munlocking */
pagevec_release(&pvec_putback);
diff --git a/mm/mmzone.c b/mm/mmzone.c
index 4686fdc23bb9..3750a90ed4a0 100644
--- a/mm/mmzone.c
+++ b/mm/mmzone.c
@@ -91,6 +91,7 @@ void lruvec_init(struct lruvec *lruvec)
enum lru_list lru;
memset(lruvec, 0, sizeof(struct lruvec));
+ spin_lock_init(&lruvec->lru_lock);
for_each_lru(lru)
INIT_LIST_HEAD(&lruvec->lists[lru]);
diff --git a/mm/page_idle.c b/mm/page_idle.c
index 295512465065..d2d868ca2bf7 100644
--- a/mm/page_idle.c
+++ b/mm/page_idle.c
@@ -31,7 +31,7 @@
static struct page *page_idle_get_page(unsigned long pfn)
{
struct page *page;
- pg_data_t *pgdat;
+ struct lruvec *lruvec;
if (!pfn_valid(pfn))
return NULL;
@@ -41,13 +41,12 @@ static struct page *page_idle_get_page(unsigned long pfn)
!get_page_unless_zero(page))
return NULL;
- pgdat = page_pgdat(page);
- spin_lock_irq(&pgdat->lru_lock);
+ lruvec = lock_page_lruvec_irq(page);
if (unlikely(!PageLRU(page))) {
put_page(page);
page = NULL;
}
- spin_unlock_irq(&pgdat->lru_lock);
+ unlock_page_lruvec_irq(lruvec);
return page;
}
diff --git a/mm/swap.c b/mm/swap.c
index 5341ae93861f..97e108be4f92 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -60,16 +60,14 @@
static void __page_cache_release(struct page *page)
{
if (PageLRU(page)) {
- pg_data_t *pgdat = page_pgdat(page);
struct lruvec *lruvec;
- unsigned long flags;
+ unsigned long flags = 0;
- spin_lock_irqsave(&pgdat->lru_lock, flags);
- lruvec = mem_cgroup_page_lruvec(page, pgdat);
+ lruvec = lock_page_lruvec_irqsave(page, &flags);
VM_BUG_ON_PAGE(!PageLRU(page), page);
__ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_off_lru(page));
- spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+ unlock_page_lruvec_irqrestore(lruvec, flags);
}
__ClearPageWaiters(page);
}
@@ -192,26 +190,18 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
void *arg)
{
int i;
- struct pglist_data *pgdat = NULL;
- struct lruvec *lruvec;
+ struct lruvec *lruvec = NULL;
unsigned long flags = 0;
for (i = 0; i < pagevec_count(pvec); i++) {
struct page *page = pvec->pages[i];
- struct pglist_data *pagepgdat = page_pgdat(page);
- if (pagepgdat != pgdat) {
- if (pgdat)
- spin_unlock_irqrestore(&pgdat->lru_lock, flags);
- pgdat = pagepgdat;
- spin_lock_irqsave(&pgdat->lru_lock, flags);
- }
+ lruvec = lock_page_lruvec_irqsave(page, &flags);
- lruvec = mem_cgroup_page_lruvec(page, pgdat);
(*move_fn)(page, lruvec, arg);
+ unlock_page_lruvec_irqrestore(lruvec, flags);
}
- if (pgdat)
- spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+
release_pages(pvec->pages, pvec->nr);
pagevec_reinit(pvec);
}
@@ -324,12 +314,12 @@ static inline void activate_page_drain(int cpu)
void activate_page(struct page *page)
{
- pg_data_t *pgdat = page_pgdat(page);
+ struct lruvec *lruvec;
page = compound_head(page);
- spin_lock_irq(&pgdat->lru_lock);
- __activate_page(page, mem_cgroup_page_lruvec(page, pgdat), NULL);
- spin_unlock_irq(&pgdat->lru_lock);
+ lruvec = lock_page_lruvec_irq(page);
+ __activate_page(page, lruvec, NULL);
+ unlock_page_lruvec_irq(lruvec);
}
#endif
@@ -780,8 +770,7 @@ void release_pages(struct page **pages, int nr)
{
int i;
LIST_HEAD(pages_to_free);
- struct pglist_data *locked_pgdat = NULL;
- struct lruvec *lruvec;
+ struct lruvec *lruvec = NULL;
unsigned long uninitialized_var(flags);
unsigned int uninitialized_var(lock_batch);
@@ -791,21 +780,20 @@ void release_pages(struct page **pages, int nr)
/*
* Make sure the IRQ-safe lock-holding time does not get
* excessive with a continuous string of pages from the
- * same pgdat. The lock is held only if pgdat != NULL.
+ * same lruvec. The lock is held only if lruvec != NULL.
*/
- if (locked_pgdat && ++lock_batch == SWAP_CLUSTER_MAX) {
- spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags);
- locked_pgdat = NULL;
+ if (lruvec && ++lock_batch == SWAP_CLUSTER_MAX) {
+ unlock_page_lruvec_irqrestore(lruvec, flags);
+ lruvec = NULL;
}
if (is_huge_zero_page(page))
continue;
if (is_zone_device_page(page)) {
- if (locked_pgdat) {
- spin_unlock_irqrestore(&locked_pgdat->lru_lock,
- flags);
- locked_pgdat = NULL;
+ if (lruvec) {
+ unlock_page_lruvec_irqrestore(lruvec, flags);
+ lruvec = NULL;
}
/*
* ZONE_DEVICE pages that return 'false' from
@@ -822,27 +810,24 @@ void release_pages(struct page **pages, int nr)
continue;
if (PageCompound(page)) {
- if (locked_pgdat) {
- spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags);
- locked_pgdat = NULL;
+ if (lruvec) {
+ unlock_page_lruvec_irqrestore(lruvec, flags);
+ lruvec = NULL;
}
__put_compound_page(page);
continue;
}
if (PageLRU(page)) {
- struct pglist_data *pgdat = page_pgdat(page);
+ struct lruvec *new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
- if (pgdat != locked_pgdat) {
- if (locked_pgdat)
- spin_unlock_irqrestore(&locked_pgdat->lru_lock,
- flags);
+ if (new_lruvec != lruvec) {
+ if (lruvec)
+ unlock_page_lruvec_irqrestore(lruvec, flags);
lock_batch = 0;
- locked_pgdat = pgdat;
- spin_lock_irqsave(&locked_pgdat->lru_lock, flags);
+ lruvec = lock_page_lruvec_irqsave(page, &flags);
}
- lruvec = mem_cgroup_page_lruvec(page, locked_pgdat);
VM_BUG_ON_PAGE(!PageLRU(page), page);
__ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_off_lru(page));
@@ -854,8 +839,8 @@ void release_pages(struct page **pages, int nr)
list_add(&page->lru, &pages_to_free);
}
- if (locked_pgdat)
- spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags);
+ if (lruvec)
+ unlock_page_lruvec_irqrestore(lruvec, flags);
mem_cgroup_uncharge_list(&pages_to_free);
free_unref_page_list(&pages_to_free);
@@ -893,7 +878,7 @@ void lru_add_page_tail(struct page *page, struct page *page_tail,
VM_BUG_ON_PAGE(!PageHead(page), page);
VM_BUG_ON_PAGE(PageCompound(page_tail), page);
VM_BUG_ON_PAGE(PageLRU(page_tail), page);
- lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock);
+ lockdep_assert_held(&lruvec->lru_lock);
if (!list)
SetPageLRU(page_tail);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 69fb9bd9ef49..f59cf96b9e38 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1752,11 +1752,9 @@ int isolate_lru_page(struct page *page)
WARN_RATELIMIT(PageTail(page), "trying to isolate tail page");
if (PageLRU(page)) {
- pg_data_t *pgdat = page_pgdat(page);
struct lruvec *lruvec;
- spin_lock_irq(&pgdat->lru_lock);
- lruvec = mem_cgroup_page_lruvec(page, pgdat);
+ lruvec = lock_page_lruvec_irq(page);
if (PageLRU(page)) {
int lru = page_lru(page);
get_page(page);
@@ -1764,7 +1762,7 @@ int isolate_lru_page(struct page *page)
del_page_from_lru_list(page, lruvec, lru);
ret = 0;
}
- spin_unlock_irq(&pgdat->lru_lock);
+ unlock_page_lruvec_irq(lruvec);
}
return ret;
}
@@ -1829,7 +1827,6 @@ static int too_many_isolated(struct pglist_data *pgdat, int file,
static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
struct list_head *list)
{
- struct pglist_data *pgdat = lruvec_pgdat(lruvec);
int nr_pages, nr_moved = 0;
LIST_HEAD(pages_to_free);
struct page *page;
@@ -1840,9 +1837,9 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
VM_BUG_ON_PAGE(PageLRU(page), page);
list_del(&page->lru);
if (unlikely(!page_evictable(page))) {
- spin_unlock_irq(&pgdat->lru_lock);
+ spin_unlock_irq(&lruvec->lru_lock);
putback_lru_page(page);
- spin_lock_irq(&pgdat->lru_lock);
+ spin_lock_irq(&lruvec->lru_lock);
continue;
}
SetPageLRU(page);
@@ -1852,19 +1849,35 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
__ClearPageActive(page);
if (unlikely(PageCompound(page))) {
- spin_unlock_irq(&pgdat->lru_lock);
+ spin_unlock_irq(&lruvec->lru_lock);
(*get_compound_page_dtor(page))(page);
- spin_lock_irq(&pgdat->lru_lock);
+ spin_lock_irq(&lruvec->lru_lock);
} else
list_add(&page->lru, &pages_to_free);
} else {
- lruvec = mem_cgroup_page_lruvec(page, pgdat);
+ struct mem_cgroup *memcg = lock_page_memcg(page);
+ struct lruvec *plv;
+ bool relocked = false;
+
+ plv = mem_cgroup_lruvec(memcg, page_pgdat(page));
+ /* page's lruvec changed in memcg moving */
+ if (plv != lruvec) {
+ spin_unlock_irq(&lruvec->lru_lock);
+ spin_lock_irq(&plv->lru_lock);
+ relocked = true;
+ }
+
lru = page_lru(page);
nr_pages = hpage_nr_pages(page);
-
- update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
- list_add(&page->lru, &lruvec->lists[lru]);
+ update_lru_size(plv, lru, page_zonenum(page), nr_pages);
+ list_add(&page->lru, &plv->lists[lru]);
nr_moved += nr_pages;
+
+ if (relocked) {
+ spin_unlock_irq(&plv->lru_lock);
+ spin_lock_irq(&lruvec->lru_lock);
+ }
+ __unlock_page_memcg(memcg);
}
}
@@ -1923,7 +1936,7 @@ static int current_may_throttle(void)
lru_add_drain();
- spin_lock_irq(&pgdat->lru_lock);
+ spin_lock_irq(&lruvec->lru_lock);
nr_taken = isolate_lru_pages(nr_to_scan, lruvec, &page_list,
&nr_scanned, sc, lru);
@@ -1935,15 +1948,14 @@ static int current_may_throttle(void)
if (!cgroup_reclaim(sc))
__count_vm_events(item, nr_scanned);
__count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned);
- spin_unlock_irq(&pgdat->lru_lock);
-
+ spin_unlock_irq(&lruvec->lru_lock);
if (nr_taken == 0)
return 0;
nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, 0,
&stat, false);
- spin_lock_irq(&pgdat->lru_lock);
+ spin_lock_irq(&lruvec->lru_lock);
item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT;
if (!cgroup_reclaim(sc))
@@ -1956,7 +1968,7 @@ static int current_may_throttle(void)
__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
- spin_unlock_irq(&pgdat->lru_lock);
+ spin_unlock_irq(&lruvec->lru_lock);
mem_cgroup_uncharge_list(&page_list);
free_unref_page_list(&page_list);
@@ -2009,7 +2021,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
lru_add_drain();
- spin_lock_irq(&pgdat->lru_lock);
+ spin_lock_irq(&lruvec->lru_lock);
nr_taken = isolate_lru_pages(nr_to_scan, lruvec, &l_hold,
&nr_scanned, sc, lru);
@@ -2020,7 +2032,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
__count_vm_events(PGREFILL, nr_scanned);
__count_memcg_events(lruvec_memcg(lruvec), PGREFILL, nr_scanned);
- spin_unlock_irq(&pgdat->lru_lock);
+ spin_unlock_irq(&lruvec->lru_lock);
while (!list_empty(&l_hold)) {
cond_resched();
@@ -2066,7 +2078,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
/*
* Move pages back to the lru list.
*/
- spin_lock_irq(&pgdat->lru_lock);
+ spin_lock_irq(&lruvec->lru_lock);
/*
* Count referenced pages from currently used mappings as rotated,
* even though only some of them are actually re-activated. This
@@ -2084,7 +2096,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate);
__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
- spin_unlock_irq(&pgdat->lru_lock);
+ spin_unlock_irq(&lruvec->lru_lock);
mem_cgroup_uncharge_list(&l_active);
free_unref_page_list(&l_active);
@@ -2369,7 +2381,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE, MAX_NR_ZONES) +
lruvec_lru_size(lruvec, LRU_INACTIVE_FILE, MAX_NR_ZONES);
- spin_lock_irq(&pgdat->lru_lock);
+ spin_lock_irq(&lruvec->lru_lock);
if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) {
reclaim_stat->recent_scanned[0] /= 2;
reclaim_stat->recent_rotated[0] /= 2;
@@ -2390,7 +2402,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
fp = file_prio * (reclaim_stat->recent_scanned[1] + 1);
fp /= reclaim_stat->recent_rotated[1] + 1;
- spin_unlock_irq(&pgdat->lru_lock);
+ spin_unlock_irq(&lruvec->lru_lock);
fraction[0] = ap;
fraction[1] = fp;
@@ -4283,24 +4295,21 @@ int page_evictable(struct page *page)
*/
void check_move_unevictable_pages(struct pagevec *pvec)
{
- struct lruvec *lruvec;
- struct pglist_data *pgdat = NULL;
+ struct lruvec *lruvec = NULL;
int pgscanned = 0;
int pgrescued = 0;
int i;
for (i = 0; i < pvec->nr; i++) {
struct page *page = pvec->pages[i];
- struct pglist_data *pagepgdat = page_pgdat(page);
+ struct lruvec *new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
pgscanned++;
- if (pagepgdat != pgdat) {
- if (pgdat)
- spin_unlock_irq(&pgdat->lru_lock);
- pgdat = pagepgdat;
- spin_lock_irq(&pgdat->lru_lock);
+ if (lruvec != new_lruvec) {
+ if (lruvec)
+ unlock_page_lruvec_irq(lruvec);
+ lruvec = lock_page_lruvec_irq(page);
}
- lruvec = mem_cgroup_page_lruvec(page, pgdat);
if (!PageLRU(page) || !PageUnevictable(page))
continue;
@@ -4316,10 +4325,10 @@ void check_move_unevictable_pages(struct pagevec *pvec)
}
}
- if (pgdat) {
+ if (lruvec) {
__count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued);
__count_vm_events(UNEVICTABLE_PGSCANNED, pgscanned);
- spin_unlock_irq(&pgdat->lru_lock);
+ unlock_page_lruvec_irq(lruvec);
}
}
EXPORT_SYMBOL_GPL(check_move_unevictable_pages);
--
1.8.3.1
^ permalink raw reply [flat|nested] 11+ messages in thread* [PATCH v5 7/8] mm/lru: revise the comments of lru_lock
2019-12-10 11:46 [PATCH v5 0/8] per lruvec lru_lock for memcg Alex Shi
` (5 preceding siblings ...)
2019-12-10 11:46 ` [PATCH v5 6/8] mm/pgdat: remove pgdat lru_lock Alex Shi
@ 2019-12-10 11:46 ` Alex Shi
2019-12-10 11:46 ` [PATCH v5 8/8] mm/lru: debug checking for page memcg moving and lock_page_memcg Alex Shi
7 siblings, 0 replies; 11+ messages in thread
From: Alex Shi @ 2019-12-10 11:46 UTC (permalink / raw)
To: cgroups, linux-kernel, linux-mm, akpm, mgorman, tj, hughd,
khlebnikov, daniel.m.jordan, yang.shi, willy, shakeelb, hannes
Cc: Alex Shi, Jason Gunthorpe, Dan Williams, Vlastimil Babka,
Ira Weiny, Jesper Dangaard Brouer, Andrey Ryabinin, Jann Horn,
Logan Gunthorpe, Souptick Joarder, Ralph Campbell,
Tobin C. Harding, Michal Hocko, Oscar Salvador, Wei Yang,
Arun KS, Darrick J. Wong, Amir Goldstein, Dave Chinner,
Josef Bacik, Kirill A. Shutemov, Jérôme Glisse,
Mike Kravetz, Kirill Tkhai, Yafang Shao
From: Hugh Dickins <hughd@google.com>
Since we changed the pgdat->lru_lock to lruvec->lru_lock, it's time to
fix the incorrect comments in code. Also fixed some zone->lru_lock comment
error from ancient time. etc.
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Jann Horn <jannh@google.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Tobin C. Harding" <tobin@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: cgroups@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
---
Documentation/admin-guide/cgroup-v1/memcg_test.rst | 15 +++------------
Documentation/admin-guide/cgroup-v1/memory.rst | 6 +++---
Documentation/trace/events-kmem.rst | 2 +-
Documentation/vm/unevictable-lru.rst | 22 ++++++++--------------
include/linux/mm_types.h | 2 +-
include/linux/mmzone.h | 2 +-
mm/filemap.c | 4 ++--
mm/rmap.c | 2 +-
mm/vmscan.c | 12 ++++++++----
9 files changed, 28 insertions(+), 39 deletions(-)
diff --git a/Documentation/admin-guide/cgroup-v1/memcg_test.rst b/Documentation/admin-guide/cgroup-v1/memcg_test.rst
index 3f7115e07b5d..0b9f91589d3d 100644
--- a/Documentation/admin-guide/cgroup-v1/memcg_test.rst
+++ b/Documentation/admin-guide/cgroup-v1/memcg_test.rst
@@ -133,18 +133,9 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y.
8. LRU
======
- Each memcg has its own private LRU. Now, its handling is under global
- VM's control (means that it's handled under global pgdat->lru_lock).
- Almost all routines around memcg's LRU is called by global LRU's
- list management functions under pgdat->lru_lock.
-
- A special function is mem_cgroup_isolate_pages(). This scans
- memcg's private LRU and call __isolate_lru_page() to extract a page
- from LRU.
-
- (By __isolate_lru_page(), the page is removed from both of global and
- private LRU.)
-
+ Each memcg has its own vector of LRUs (inactive anon, active anon,
+ inactive file, active file, unevictable) of pages from each node,
+ each LRU handled under a single lru_lock for that memcg and node.
9. Typical Tests.
=================
diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst
index 0ae4f564c2d6..60d97e8b7f3c 100644
--- a/Documentation/admin-guide/cgroup-v1/memory.rst
+++ b/Documentation/admin-guide/cgroup-v1/memory.rst
@@ -297,13 +297,13 @@ When oom event notifier is registered, event will be delivered.
PG_locked.
mm->page_table_lock
- pgdat->lru_lock
+ lruvec->lru_lock
lock_page_cgroup.
In many cases, just lock_page_cgroup() is called.
- per-zone-per-cgroup LRU (cgroup's private LRU) is just guarded by
- pgdat->lru_lock, it has no lock of its own.
+ per-node-per-cgroup LRU (cgroup's private LRU) is just guarded by
+ lruvec->lru_lock, it has no lock of its own.
2.7 Kernel Memory Extension (CONFIG_MEMCG_KMEM)
-----------------------------------------------
diff --git a/Documentation/trace/events-kmem.rst b/Documentation/trace/events-kmem.rst
index 555484110e36..68fa75247488 100644
--- a/Documentation/trace/events-kmem.rst
+++ b/Documentation/trace/events-kmem.rst
@@ -69,7 +69,7 @@ When pages are freed in batch, the also mm_page_free_batched is triggered.
Broadly speaking, pages are taken off the LRU lock in bulk and
freed in batch with a page list. Significant amounts of activity here could
indicate that the system is under memory pressure and can also indicate
-contention on the zone->lru_lock.
+contention on the lruvec->lru_lock.
4. Per-CPU Allocator Activity
=============================
diff --git a/Documentation/vm/unevictable-lru.rst b/Documentation/vm/unevictable-lru.rst
index 17d0861b0f1d..0e1490524f53 100644
--- a/Documentation/vm/unevictable-lru.rst
+++ b/Documentation/vm/unevictable-lru.rst
@@ -33,7 +33,7 @@ reclaim in Linux. The problems have been observed at customer sites on large
memory x86_64 systems.
To illustrate this with an example, a non-NUMA x86_64 platform with 128GB of
-main memory will have over 32 million 4k pages in a single zone. When a large
+main memory will have over 32 million 4k pages in a single node. When a large
fraction of these pages are not evictable for any reason [see below], vmscan
will spend a lot of time scanning the LRU lists looking for the small fraction
of pages that are evictable. This can result in a situation where all CPUs are
@@ -55,7 +55,7 @@ unevictable, either by definition or by circumstance, in the future.
The Unevictable Page List
-------------------------
-The Unevictable LRU infrastructure consists of an additional, per-zone, LRU list
+The Unevictable LRU infrastructure consists of an additional, per-node, LRU list
called the "unevictable" list and an associated page flag, PG_unevictable, to
indicate that the page is being managed on the unevictable list.
@@ -84,15 +84,9 @@ The unevictable list does not differentiate between file-backed and anonymous,
swap-backed pages. This differentiation is only important while the pages are,
in fact, evictable.
-The unevictable list benefits from the "arrayification" of the per-zone LRU
+The unevictable list benefits from the "arrayification" of the per-node LRU
lists and statistics originally proposed and posted by Christoph Lameter.
-The unevictable list does not use the LRU pagevec mechanism. Rather,
-unevictable pages are placed directly on the page's zone's unevictable list
-under the zone lru_lock. This allows us to prevent the stranding of pages on
-the unevictable list when one task has the page isolated from the LRU and other
-tasks are changing the "evictability" state of the page.
-
Memory Control Group Interaction
--------------------------------
@@ -101,8 +95,8 @@ The unevictable LRU facility interacts with the memory control group [aka
memory controller; see Documentation/admin-guide/cgroup-v1/memory.rst] by extending the
lru_list enum.
-The memory controller data structure automatically gets a per-zone unevictable
-list as a result of the "arrayification" of the per-zone LRU lists (one per
+The memory controller data structure automatically gets a per-node unevictable
+list as a result of the "arrayification" of the per-node LRU lists (one per
lru_list enum element). The memory controller tracks the movement of pages to
and from the unevictable list.
@@ -196,7 +190,7 @@ for the sake of expediency, to leave a unevictable page on one of the regular
active/inactive LRU lists for vmscan to deal with. vmscan checks for such
pages in all of the shrink_{active|inactive|page}_list() functions and will
"cull" such pages that it encounters: that is, it diverts those pages to the
-unevictable list for the zone being scanned.
+unevictable list for the node being scanned.
There may be situations where a page is mapped into a VM_LOCKED VMA, but the
page is not marked as PG_mlocked. Such pages will make it all the way to
@@ -328,7 +322,7 @@ If the page was NOT already mlocked, mlock_vma_page() attempts to isolate the
page from the LRU, as it is likely on the appropriate active or inactive list
at that time. If the isolate_lru_page() succeeds, mlock_vma_page() will put
back the page - by calling putback_lru_page() - which will notice that the page
-is now mlocked and divert the page to the zone's unevictable list. If
+is now mlocked and divert the page to the node's unevictable list. If
mlock_vma_page() is unable to isolate the page from the LRU, vmscan will handle
it later if and when it attempts to reclaim the page.
@@ -603,7 +597,7 @@ Some examples of these unevictable pages on the LRU lists are:
unevictable list in mlock_vma_page().
shrink_inactive_list() also diverts any unevictable pages that it finds on the
-inactive lists to the appropriate zone's unevictable list.
+inactive lists to the appropriate node's unevictable list.
shrink_inactive_list() should only see SHM_LOCK'd pages that became SHM_LOCK'd
after shrink_active_list() had moved them to the inactive list, or pages mapped
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 270aa8fd2800..ff08a6a8145c 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -78,7 +78,7 @@ struct page {
struct { /* Page cache and anonymous pages */
/**
* @lru: Pageout list, eg. active_list protected by
- * pgdat->lru_lock. Sometimes used as a generic list
+ * lruvec->lru_lock. Sometimes used as a generic list
* by the page owner.
*/
struct list_head lru;
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index a9334c8d42c8..58ce3186df78 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -115,7 +115,7 @@ static inline bool free_area_empty(struct free_area *area, int migratetype)
struct pglist_data;
/*
- * zone->lock and the zone lru_lock are two of the hottest locks in the kernel.
+ * zone->lock and the lru_lock are two of the hottest locks in the kernel.
* So add a wild amount of padding here to ensure that they fall into separate
* cachelines. There are very few zone structures in the machine, so space
* consumption is not a concern here.
diff --git a/mm/filemap.c b/mm/filemap.c
index 1f5731768222..65236af31db3 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -101,8 +101,8 @@
* ->swap_lock (try_to_unmap_one)
* ->private_lock (try_to_unmap_one)
* ->i_pages lock (try_to_unmap_one)
- * ->pgdat->lru_lock (follow_page->mark_page_accessed)
- * ->pgdat->lru_lock (check_pte_range->isolate_lru_page)
+ * ->lruvec->lru_lock (follow_page->mark_page_accessed)
+ * ->lruvec->lru_lock (check_pte_range->isolate_lru_page)
* ->private_lock (page_remove_rmap->set_page_dirty)
* ->i_pages lock (page_remove_rmap->set_page_dirty)
* bdi.wb->list_lock (page_remove_rmap->set_page_dirty)
diff --git a/mm/rmap.c b/mm/rmap.c
index 95f381bbaf7f..b32a15d34a9e 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -27,7 +27,7 @@
* mapping->i_mmap_rwsem
* anon_vma->rwsem
* mm->page_table_lock or pte_lock
- * pgdat->lru_lock (in mark_page_accessed, isolate_lru_page)
+ * lruvec->lru_lock (in mark_page_accessed, isolate_lru_page)
* swap_lock (in swap_duplicate, swap_info_get)
* mmlist_lock (in mmput, drain_mmlist and others)
* mapping->private_lock (in __set_page_dirty_buffers)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index ecad34c9e167..6be0bd24ad2f 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1612,14 +1612,16 @@ static __always_inline void update_lru_sizes(struct lruvec *lruvec,
}
/**
- * pgdat->lru_lock is heavily contended. Some of the functions that
+ * Isolating page from the lruvec to fill in @dst list by nr_to_scan times.
+ *
+ * lruvec->lru_lock is heavily contended. Some of the functions that
* shrink the lists perform better by taking out a batch of pages
* and working on them outside the LRU lock.
*
* For pagecache intensive workloads, this function is the hottest
* spot in the kernel (apart from copy_*_user functions).
*
- * Appropriate locks must be held before calling this function.
+ * Lru_lock must be held before calling this function.
*
* @nr_to_scan: The number of eligible pages to look through on the list.
* @lruvec: The LRU vector to pull pages from.
@@ -1806,14 +1808,16 @@ static int too_many_isolated(struct pglist_data *pgdat, int file,
/*
* This moves pages from @list to corresponding LRU list.
+ * The pages from @list is out of any lruvec, and in the end list reuses as
+ * pages_to_free list.
*
* We move them the other way if the page is referenced by one or more
* processes, from rmap.
*
* If the pages are mostly unmapped, the processing is fast and it is
- * appropriate to hold zone_lru_lock across the whole operation. But if
+ * appropriate to hold lru_lock across the whole operation. But if
* the pages are mapped, the processing is slow (page_referenced()) so we
- * should drop zone_lru_lock around each page. It's impossible to balance
+ * should drop lru_lock around each page. It's impossible to balance
* this, so instead we remove the pages from the LRU while processing them.
* It is safe to rely on PG_active against the non-LRU pages in here because
* nobody will play with that bit on a non-LRU page.
--
1.8.3.1
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