Commit 1ff9e6e1 authored by Chris Down's avatar Chris Down Committed by Linus Torvalds
Browse files

mm: memcontrol: expose THP events on a per-memcg basis 

Currently THP allocation events data is fairly opaque, since you can
only get it system-wide.  This patch makes it easier to reason about
transparent hugepage behaviour on a per-memcg basis.

For anonymous THP-backed pages, we already have MEMCG_RSS_HUGE in v1,
which is used for v1's rss_huge [sic].  This is reused here as it's
fairly involved to untangle NR_ANON_THPS right now to make it per-memcg,
since right now some of this is delegated to rmap before we have any
memcg actually assigned to the page.  It's a good idea to rework that,
but let's leave untangling THP allocation for a future patch.

[akpm@linux-foundation.org: fix build]
[chris@chrisdown.name: fix memcontrol build when THP is disabled]
  Link: http://lkml.kernel.org/r/20190131160802.GA5777@chrisdown.name
Link: http://lkml.kernel.org/r/20190129205852.GA7310@chrisdown.name


Signed-off-by: default avatarChris Down <chris@chrisdown.name>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2bb0f34f

Documentation/admin-guide/cgroup-v2.rst

+16 −0
Original line number Diff line number Diff line
@@ -1189,6 +1189,10 @@ PAGE_SIZE multiple when read back. 
		Amount of cached filesystem data that was modified and

		is currently being written back to disk



	  anon_thp

		Amount of memory used in anonymous mappings backed by

		transparent hugepages



	  inactive_anon, active_anon, inactive_file, active_file, unevictable

		Amount of memory, swap-backed and filesystem-backed,

		on the internal memory management lists used by the
@@ -1248,6 +1252,18 @@ PAGE_SIZE multiple when read back. 


		Amount of reclaimed lazyfree pages



	  thp_fault_alloc



		Number of transparent hugepages which were allocated to satisfy

		a page fault, including COW faults. This counter is not present

		when CONFIG_TRANSPARENT_HUGEPAGE is not set.



	  thp_collapse_alloc



		Number of transparent hugepages which were allocated to allow

		collapsing an existing range of pages. This counter is not

		present when CONFIG_TRANSPARENT_HUGEPAGE is not set.



  memory.swap.current

	A read-only single value file which exists on non-root

	cgroups.

mm/huge_memory.c

+2 −0
Original line number Diff line number Diff line
@@ -617,6 +617,7 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, 
		mm_inc_nr_ptes(vma->vm_mm);

		spin_unlock(vmf->ptl);

		count_vm_event(THP_FAULT_ALLOC);

		count_memcg_events(memcg, THP_FAULT_ALLOC, 1);

	}



	return 0;
@@ -1338,6 +1339,7 @@ alloc: 
	}



	count_vm_event(THP_FAULT_ALLOC);

	count_memcg_events(memcg, THP_FAULT_ALLOC, 1);



	if (!page)

		clear_huge_page(new_page, vmf->address, HPAGE_PMD_NR);

mm/khugepaged.c

+2 −0
Original line number Diff line number Diff line
@@ -1074,6 +1074,7 @@ static void collapse_huge_page(struct mm_struct *mm, 
	BUG_ON(!pmd_none(*pmd));

	page_add_new_anon_rmap(new_page, vma, address, true);

	mem_cgroup_commit_charge(new_page, memcg, false, true);

	count_memcg_events(memcg, THP_COLLAPSE_ALLOC, 1);

	lru_cache_add_active_or_unevictable(new_page, vma);

	pgtable_trans_huge_deposit(mm, pmd, pgtable);

	set_pmd_at(mm, address, pmd, _pmd);
@@ -1502,6 +1503,7 @@ xa_unlocked: 
		page_ref_add(new_page, HPAGE_PMD_NR - 1);

		set_page_dirty(new_page);

		mem_cgroup_commit_charge(new_page, memcg, false, true);

		count_memcg_events(memcg, THP_COLLAPSE_ALLOC, 1);

		lru_cache_add_anon(new_page);



		/*

mm/memcontrol.c

+16 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ 
#include <linux/shmem_fs.h>

#include <linux/hugetlb.h>

#include <linux/pagemap.h>

#include <linux/vm_event_item.h>

#include <linux/smp.h>

#include <linux/page-flags.h>

#include <linux/backing-dev.h>
@@ -5571,6 +5572,15 @@ static int memory_stat_show(struct seq_file *m, void *v) 
	seq_printf(m, "file_writeback %llu\n",

		   (u64)acc.stat[NR_WRITEBACK] * PAGE_SIZE);



	/*

	 * TODO: We should eventually replace our own MEMCG_RSS_HUGE counter

	 * with the NR_ANON_THP vm counter, but right now it's a pain in the

	 * arse because it requires migrating the work out of rmap to a place

	 * where the page->mem_cgroup is set up and stable.

	 */

	seq_printf(m, "anon_thp %llu\n",

		   (u64)acc.stat[MEMCG_RSS_HUGE] * PAGE_SIZE);



	for (i = 0; i < NR_LRU_LISTS; i++)

		seq_printf(m, "%s %llu\n", mem_cgroup_lru_names[i],

			   (u64)acc.lru_pages[i] * PAGE_SIZE);
@@ -5602,6 +5612,12 @@ static int memory_stat_show(struct seq_file *m, void *v) 
	seq_printf(m, "pglazyfree %lu\n", acc.events[PGLAZYFREE]);

	seq_printf(m, "pglazyfreed %lu\n", acc.events[PGLAZYFREED]);



#ifdef CONFIG_TRANSPARENT_HUGEPAGE

	seq_printf(m, "thp_fault_alloc %lu\n", acc.events[THP_FAULT_ALLOC]);

	seq_printf(m, "thp_collapse_alloc %lu\n",

		   acc.events[THP_COLLAPSE_ALLOC]);

#endif /* CONFIG_TRANSPARENT_HUGEPAGE */



	return 0;

}

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