[PATCH v4 1/3] mm, memcg: add mem_cgroup_disabled checks in vmpressure and swap-related functions

Subsystems: control group - memory resource controller (memcg), memory management, memory management - core, memory management - swap, the rest

STALE1891d REVIEWED: 13 (11M)

4 review trailers (2 from subsystem maintainers).

3 messages, 1 author, 2021-07-13 · open the first message on its own page

[PATCH v4 1/3] mm, memcg: add mem_cgroup_disabled checks in vmpressure and swap-related functions

From: Suren Baghdasaryan <surenb@google.com>
Date: 2021-07-13 01:09:41

Add mem_cgroup_disabled check in vmpressure, mem_cgroup_uncharge_swap and
cgroup_throttle_swaprate functions. This minimizes the memcg overhead in
the pagefault and exit_mmap paths when memcgs are disabled using
cgroup_disable=memory command-line option.
This change results in ~2.1% overhead reduction when running PFT test [1]
comparing {CONFIG_MEMCG=n, CONFIG_MEMCG_SWAP=n} against {CONFIG_MEMCG=y,
CONFIG_MEMCG_SWAP=y, cgroup_disable=memory} configuration on an 8-core
ARM64 Android device.

[1] https://lkml.org/lkml/2006/8/29/294 also used in mmtests suite

Signed-off-by: Suren Baghdasaryan <redacted>
Reviewed-by: Shakeel Butt <redacted>
Reviewed-by: Muchun Song <redacted>
Acked-by: Johannes Weiner <redacted>
Acked-by: Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>
---
 mm/memcontrol.c | 3 +++
 mm/swapfile.c   | 3 +++
 mm/vmpressure.c | 7 ++++++-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ae1f5d0cb581..a228cd51c4bd 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c

@@ -7305,6 +7305,9 @@ void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
 	struct mem_cgroup *memcg;
 	unsigned short id;
 
+	if (mem_cgroup_disabled())
+		return;
+
 	id = swap_cgroup_record(entry, 0, nr_pages);
 	rcu_read_lock();
 	memcg = mem_cgroup_from_id(id);

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 1e07d1c776f2..707fa0481bb4 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c

@@ -3778,6 +3778,9 @@ void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
 	struct swap_info_struct *si, *next;
 	int nid = page_to_nid(page);
 
+	if (mem_cgroup_disabled())
+		return;
+
 	if (!(gfp_mask & __GFP_IO))
 		return;

diff --git a/mm/vmpressure.c b/mm/vmpressure.c
index d69019fc3789..9b172561fded 100644
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c

@@ -240,7 +240,12 @@ static void vmpressure_work_fn(struct work_struct *work)
 void vmpressure(gfp_t gfp, struct mem_cgroup *memcg, bool tree,
 		unsigned long scanned, unsigned long reclaimed)
 {
-	struct vmpressure *vmpr = memcg_to_vmpressure(memcg);
+	struct vmpressure *vmpr;
+
+	if (mem_cgroup_disabled())
+		return;
+
+	vmpr = memcg_to_vmpressure(memcg);
 
 	/*
 	 * Here we only want to account pressure that userland is able to

-- 
2.32.0.93.g670b81a890-goog

[PATCH v4 2/3] mm, memcg: inline mem_cgroup_{charge/uncharge} to improve disabled memcg config

From: Suren Baghdasaryan <surenb@google.com>
Date: 2021-07-13 01:09:45

Inline mem_cgroup_{charge/uncharge} and mem_cgroup_uncharge_list functions
functions to perform mem_cgroup_disabled static key check inline before
calling the main body of the function. This minimizes the memcg overhead
in the pagefault and exit_mmap paths when memcgs are disabled using
cgroup_disable=memory command-line option.
This change results in ~0.4% overhead reduction when running PFT test [1]
comparing {CONFIG_MEMCG=n} against {CONFIG_MEMCG=y, cgroup_disable=memory}
configuration on an 8-core ARM64 Android device.

[1] https://lkml.org/lkml/2006/8/29/294 also used in mmtests suite

Signed-off-by: Suren Baghdasaryan <redacted>
Reviewed-by: Shakeel Butt <redacted>
Reviewed-by: Muchun Song <redacted>
Acked-by: Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>
Acked-by: Johannes Weiner <redacted>
---
 include/linux/memcontrol.h | 28 +++++++++++++++++++++++++---
 mm/memcontrol.c            | 33 ++++++++++++---------------------
 2 files changed, 37 insertions(+), 24 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index bfe5c486f4ad..39fa88051a42 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h

@@ -693,13 +693,35 @@ static inline bool mem_cgroup_below_min(struct mem_cgroup *memcg)
 		page_counter_read(&memcg->memory);
 }
 
-int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask);
+int __mem_cgroup_charge(struct page *page, struct mm_struct *mm,
+			gfp_t gfp_mask);
+static inline int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
+				    gfp_t gfp_mask)
+{
+	if (mem_cgroup_disabled())
+		return 0;
+	return __mem_cgroup_charge(page, mm, gfp_mask);
+}
+
 int mem_cgroup_swapin_charge_page(struct page *page, struct mm_struct *mm,
 				  gfp_t gfp, swp_entry_t entry);
 void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry);
 
-void mem_cgroup_uncharge(struct page *page);
-void mem_cgroup_uncharge_list(struct list_head *page_list);
+void __mem_cgroup_uncharge(struct page *page);
+static inline void mem_cgroup_uncharge(struct page *page)
+{
+	if (mem_cgroup_disabled())
+		return;
+	__mem_cgroup_uncharge(page);
+}
+
+void __mem_cgroup_uncharge_list(struct list_head *page_list);
+static inline void mem_cgroup_uncharge_list(struct list_head *page_list)
+{
+	if (mem_cgroup_disabled())
+		return;
+	__mem_cgroup_uncharge_list(page_list);
+}
 
 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage);

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a228cd51c4bd..6adf50acdbe2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c

@@ -6701,8 +6701,7 @@ void mem_cgroup_calculate_protection(struct mem_cgroup *root,
 			atomic_long_read(&parent->memory.children_low_usage)));
 }
 
-static int __mem_cgroup_charge(struct page *page, struct mem_cgroup *memcg,
-			       gfp_t gfp)
+static int charge_memcg(struct page *page, struct mem_cgroup *memcg, gfp_t gfp)
 {
 	unsigned int nr_pages = thp_nr_pages(page);
 	int ret;

@@ -6723,7 +6722,7 @@ static int __mem_cgroup_charge(struct page *page, struct mem_cgroup *memcg,
 }
 
 /**
- * mem_cgroup_charge - charge a newly allocated page to a cgroup
+ * __mem_cgroup_charge - charge a newly allocated page to a cgroup
  * @page: page to charge
  * @mm: mm context of the victim
  * @gfp_mask: reclaim mode

@@ -6736,16 +6735,14 @@ static int __mem_cgroup_charge(struct page *page, struct mem_cgroup *memcg,
  *
  * Returns 0 on success. Otherwise, an error code is returned.
  */
-int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
+int __mem_cgroup_charge(struct page *page, struct mm_struct *mm,
+			gfp_t gfp_mask)
 {
 	struct mem_cgroup *memcg;
 	int ret;
 
-	if (mem_cgroup_disabled())
-		return 0;
-
 	memcg = get_mem_cgroup_from_mm(mm);
-	ret = __mem_cgroup_charge(page, memcg, gfp_mask);
+	ret = charge_memcg(page, memcg, gfp_mask);
 	css_put(&memcg->css);
 
 	return ret;

@@ -6780,7 +6777,7 @@ int mem_cgroup_swapin_charge_page(struct page *page, struct mm_struct *mm,
 		memcg = get_mem_cgroup_from_mm(mm);
 	rcu_read_unlock();
 
-	ret = __mem_cgroup_charge(page, memcg, gfp);
+	ret = charge_memcg(page, memcg, gfp);
 
 	css_put(&memcg->css);
 	return ret;

@@ -6916,18 +6913,15 @@ static void uncharge_page(struct page *page, struct uncharge_gather *ug)
 }
 
 /**
- * mem_cgroup_uncharge - uncharge a page
+ * __mem_cgroup_uncharge - uncharge a page
  * @page: page to uncharge
  *
- * Uncharge a page previously charged with mem_cgroup_charge().
+ * Uncharge a page previously charged with __mem_cgroup_charge().
  */
-void mem_cgroup_uncharge(struct page *page)
+void __mem_cgroup_uncharge(struct page *page)
 {
 	struct uncharge_gather ug;
 
-	if (mem_cgroup_disabled())
-		return;
-
 	/* Don't touch page->lru of any random page, pre-check: */
 	if (!page_memcg(page))
 		return;

@@ -6938,20 +6932,17 @@ void mem_cgroup_uncharge(struct page *page)
 }
 
 /**
- * mem_cgroup_uncharge_list - uncharge a list of page
+ * __mem_cgroup_uncharge_list - uncharge a list of page
  * @page_list: list of pages to uncharge
  *
  * Uncharge a list of pages previously charged with
- * mem_cgroup_charge().
+ * __mem_cgroup_charge().
  */
-void mem_cgroup_uncharge_list(struct list_head *page_list)
+void __mem_cgroup_uncharge_list(struct list_head *page_list)
 {
 	struct uncharge_gather ug;
 	struct page *page;
 
-	if (mem_cgroup_disabled())
-		return;
-
 	uncharge_gather_clear(&ug);
 	list_for_each_entry(page, page_list, lru)
 		uncharge_page(page, &ug);

-- 
2.32.0.93.g670b81a890-goog

[PATCH v4 3/3] mm, memcg: inline swap-related functions to improve disabled memcg config

From: Suren Baghdasaryan <surenb@google.com>
Date: 2021-07-13 01:09:47

Inline mem_cgroup_try_charge_swap, mem_cgroup_uncharge_swap and
cgroup_throttle_swaprate functions to perform mem_cgroup_disabled static
key check inline before calling the main body of the function. This
minimizes the memcg overhead in the pagefault and exit_mmap paths when
memcgs are disabled using cgroup_disable=memory command-line option.
This change results in ~1% overhead reduction when running PFT test [1]
comparing {CONFIG_MEMCG=n} against {CONFIG_MEMCG=y, cgroup_disable=memory}
configuration on an 8-core ARM64 Android device.

[1] https://lkml.org/lkml/2006/8/29/294 also used in mmtests suite

Signed-off-by: Suren Baghdasaryan <redacted>
Reviewed-by: Shakeel Butt <redacted>
Reviewed-by: Muchun Song <redacted>
Acked-by: Johannes Weiner <redacted>
Acked-by: Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>
---
 include/linux/swap.h | 26 +++++++++++++++++++++++---
 mm/memcontrol.c      | 14 ++++----------
 mm/swapfile.c        |  5 +----
 3 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 6f5a43251593..f30d26b0f71d 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h

@@ -721,7 +721,13 @@ static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
 #endif
 
 #if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
-extern void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask);
+extern void __cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask);
+static inline  void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
+{
+	if (mem_cgroup_disabled())
+		return;
+	__cgroup_throttle_swaprate(page, gfp_mask);
+}
 #else
 static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
 {

@@ -730,8 +736,22 @@ static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
 
 #ifdef CONFIG_MEMCG_SWAP
 extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
-extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
-extern void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
+extern int __mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
+static inline int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
+{
+	if (mem_cgroup_disabled())
+		return 0;
+	return __mem_cgroup_try_charge_swap(page, entry);
+}
+
+extern void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages);
+static inline void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
+{
+	if (mem_cgroup_disabled())
+		return;
+	__mem_cgroup_uncharge_swap(entry, nr_pages);
+}
+
 extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg);
 extern bool mem_cgroup_swap_full(struct page *page);
 #else

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6adf50acdbe2..b8aab1900995 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c

@@ -7234,7 +7234,7 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
 }
 
 /**
- * mem_cgroup_try_charge_swap - try charging swap space for a page
+ * __mem_cgroup_try_charge_swap - try charging swap space for a page
  * @page: page being added to swap
  * @entry: swap entry to charge
  *

@@ -7242,16 +7242,13 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
  *
  * Returns 0 on success, -ENOMEM on failure.
  */
-int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
+int __mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
 {
 	unsigned int nr_pages = thp_nr_pages(page);
 	struct page_counter *counter;
 	struct mem_cgroup *memcg;
 	unsigned short oldid;
 
-	if (mem_cgroup_disabled())
-		return 0;
-
 	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
 		return 0;

@@ -7287,18 +7284,15 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
 }
 
 /**
- * mem_cgroup_uncharge_swap - uncharge swap space
+ * __mem_cgroup_uncharge_swap - uncharge swap space
  * @entry: swap entry to uncharge
  * @nr_pages: the amount of swap space to uncharge
  */
-void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
+void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
 {
 	struct mem_cgroup *memcg;
 	unsigned short id;
 
-	if (mem_cgroup_disabled())
-		return;
-
 	id = swap_cgroup_record(entry, 0, nr_pages);
 	rcu_read_lock();
 	memcg = mem_cgroup_from_id(id);

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 707fa0481bb4..04a0c83f1313 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c

@@ -3773,14 +3773,11 @@ static void free_swap_count_continuations(struct swap_info_struct *si)
 }
 
 #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
-void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
+void __cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
 {
 	struct swap_info_struct *si, *next;
 	int nid = page_to_nid(page);
 
-	if (mem_cgroup_disabled())
-		return;
-
 	if (!(gfp_mask & __GFP_IO))
 		return;

-- 
2.32.0.93.g670b81a890-goog

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