[092/212] mm, memcg: add mem_cgroup_disabled checks in vmpressure and swap-related functions

Commit Message

Andrew Morton Sept. 2, 2021, 9:54 p.m. UTC

From: Suren Baghdasaryan <[e-mail]>
Subject: mm, memcg: add mem_cgroup_disabled checks in vmpressure and swap-related functions

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

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Suren Baghdasaryan <[e-mail]>
Reviewed-by: Shakeel Butt <[e-mail]>
Reviewed-by: Muchun Song <[e-mail]>
Acked-by: Johannes Weiner <[e-mail]>
Acked-by: Michal Hocko <[e-mail]>
Cc: Alex Shi <[e-mail]>
Cc: Alistair Popple <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: Jens Axboe <[e-mail]>
Cc: Joonsoo Kim <[e-mail]>
Cc: Matthew Wilcox (Oracle) <[e-mail]>
Cc: Miaohe Lin <[e-mail]>
Cc: Minchan Kim <[e-mail]>
Cc: Roman Gushchin <[e-mail]>
Cc: Tejun Heo <[e-mail]>
Cc: Wei Yang <[e-mail]>
Cc: Yang Shi <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/memcontrol.c |    3 +++
 mm/swapfile.c   |    3 +++
 mm/vmpressure.c |    7 ++++++-
 3 files changed, 12 insertions(+), 1 deletion(-)

Patch

--- a/mm/memcontrol.c~mm-memcg-add-mem_cgroup_disabled-checks-in-vmpressure-and-swap-related-functions
+++ a/mm/memcontrol.c
@@ -7297,6 +7297,9 @@  void mem_cgroup_uncharge_swap(swp_entry_
 	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);
--- a/mm/swapfile.c~mm-memcg-add-mem_cgroup_disabled-checks-in-vmpressure-and-swap-related-functions
+++ a/mm/swapfile.c
@@ -3784,6 +3784,9 @@  void cgroup_throttle_swaprate(struct pag
 	struct swap_info_struct *si, *next;
 	int nid = page_to_nid(page);
 
+	if (mem_cgroup_disabled())
+		return;
+
 	if (!(gfp_mask & __GFP_IO))
 		return;
 
--- a/mm/vmpressure.c~mm-memcg-add-mem_cgroup_disabled-checks-in-vmpressure-and-swap-related-functions
+++ a/mm/vmpressure.c
@@ -240,7 +240,12 @@  static void vmpressure_work_fn(struct wo
 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