[PATCH v4 3/4] mm, shmem: Add shmem resident memory accounting

From: Vlastimil Babka <hidden>
Date: 2015-10-02 13:36:19
Also in: linux-mm, linux-s390, lkml
Subsystem: filesystems (vfs and infrastructure), memory management, memory management - core, memory management - oom killer, memory management - rmap (reverse mapping), memory mapping, performance events subsystem, proc filesystem, s390 architecture, the rest, uprobes · Maintainers: Alexander Viro, Christian Brauner, Andrew Morton, David Hildenbrand, Michal Hocko, Lorenzo Stoakes, Liam R. Howlett, Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Linus Torvalds, Masami Hiramatsu, Oleg Nesterov

From: Jerome Marchand <redacted>

Currently looking at /proc/<pid>/status or statm, there is no way to
distinguish shmem pages from pages mapped to a regular file (shmem
pages are mapped to /dev/zero), even though their implication in
actual memory use is quite different.
This patch adds MM_SHMEMPAGES counter to mm_rss_stat to account for
shmem pages instead of MM_FILEPAGES.

Signed-off-by: Jerome Marchand <redacted>
Signed-off-by: Vlastimil Babka <redacted>
Acked-by: Konstantin Khlebnikov <redacted>
Acked-by: Michal Hocko <mhocko@suse.com>
---
 arch/s390/mm/pgtable.c   |  5 +----
 fs/proc/task_mmu.c       |  3 ++-
 include/linux/mm.h       | 18 +++++++++++++++++-
 include/linux/mm_types.h |  7 ++++---
 kernel/events/uprobes.c  |  2 +-
 mm/memory.c              | 30 ++++++++++--------------------
 mm/oom_kill.c            |  5 +++--
 mm/rmap.c                | 12 +++---------
 8 files changed, 41 insertions(+), 41 deletions(-)

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 54ef3bc..9816f25 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c

@@ -603,10 +603,7 @@ static void gmap_zap_swap_entry(swp_entry_t entry, struct mm_struct *mm)
 	else if (is_migration_entry(entry)) {
 		struct page *page = migration_entry_to_page(entry);
 
-		if (PageAnon(page))
-			dec_mm_counter(mm, MM_ANONPAGES);
-		else
-			dec_mm_counter(mm, MM_FILEPAGES);
+		dec_mm_counter(mm, mm_counter(page));
 	}
 	free_swap_and_cache(entry);
 }

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 103457c..9b9708e 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c

@@ -83,7 +83,8 @@ unsigned long task_statm(struct mm_struct *mm,
 			 unsigned long *shared, unsigned long *text,
 			 unsigned long *data, unsigned long *resident)
 {
-	*shared = get_mm_counter(mm, MM_FILEPAGES);
+	*shared = get_mm_counter(mm, MM_FILEPAGES) +
+			get_mm_counter(mm, MM_SHMEMPAGES);
 	*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
 								>> PAGE_SHIFT;
 	*data = mm->total_vm - mm->shared_vm;

diff --git a/include/linux/mm.h b/include/linux/mm.h
index d30eea3..8be4efc 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h

@@ -1361,10 +1361,26 @@ static inline void dec_mm_counter(struct mm_struct *mm, int member)
 	atomic_long_dec(&mm->rss_stat.count[member]);
 }
 
+/* Optimized variant when page is already known not to be PageAnon */
+static inline int mm_counter_file(struct page *page)
+{
+	if (PageSwapBacked(page))
+		return MM_SHMEMPAGES;
+	return MM_FILEPAGES;
+}
+
+static inline int mm_counter(struct page *page)
+{
+	if (PageAnon(page))
+		return MM_ANONPAGES;
+	return mm_counter_file(page);
+}
+
 static inline unsigned long get_mm_rss(struct mm_struct *mm)
 {
 	return get_mm_counter(mm, MM_FILEPAGES) +
-		get_mm_counter(mm, MM_ANONPAGES);
+		get_mm_counter(mm, MM_ANONPAGES) +
+		get_mm_counter(mm, MM_SHMEMPAGES);
 }
 
 static inline unsigned long get_mm_hiwater_rss(struct mm_struct *mm)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index f8d1492..207890b 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h

@@ -369,9 +369,10 @@ struct core_state {
 };
 
 enum {
-	MM_FILEPAGES,
-	MM_ANONPAGES,
-	MM_SWAPENTS,
+	MM_FILEPAGES,	/* Resident file mapping pages */
+	MM_ANONPAGES,	/* Resident anonymous pages */
+	MM_SWAPENTS,	/* Anonymous swap entries */
+	MM_SHMEMPAGES,	/* Resident shared memory pages */
 	NR_MM_COUNTERS
 };

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 4e5e979..6288606 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c

@@ -180,7 +180,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
 	lru_cache_add_active_or_unevictable(kpage, vma);
 
 	if (!PageAnon(page)) {
-		dec_mm_counter(mm, MM_FILEPAGES);
+		dec_mm_counter(mm, mm_counter_file(page));
 		inc_mm_counter(mm, MM_ANONPAGES);
 	}

diff --git a/mm/memory.c b/mm/memory.c
index 3bd465a..f10d458 100644
--- a/mm/memory.c
+++ b/mm/memory.c

@@ -832,10 +832,7 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		} else if (is_migration_entry(entry)) {
 			page = migration_entry_to_page(entry);
 
-			if (PageAnon(page))
-				rss[MM_ANONPAGES]++;
-			else
-				rss[MM_FILEPAGES]++;
+			rss[mm_counter(page)]++;
 
 			if (is_write_migration_entry(entry) &&
 					is_cow_mapping(vm_flags)) {

@@ -874,10 +871,7 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 	if (page) {
 		get_page(page);
 		page_dup_rmap(page);
-		if (PageAnon(page))
-			rss[MM_ANONPAGES]++;
-		else
-			rss[MM_FILEPAGES]++;
+		rss[mm_counter(page)]++;
 	}
 
 out_set_pte:

@@ -1113,9 +1107,8 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
 			tlb_remove_tlb_entry(tlb, pte, addr);
 			if (unlikely(!page))
 				continue;
-			if (PageAnon(page))
-				rss[MM_ANONPAGES]--;
-			else {
+
+			if (!PageAnon(page)) {
 				if (pte_dirty(ptent)) {
 					force_flush = 1;
 					set_page_dirty(page);

@@ -1123,8 +1116,8 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
 				if (pte_young(ptent) &&
 				    likely(!(vma->vm_flags & VM_SEQ_READ)))
 					mark_page_accessed(page);
-				rss[MM_FILEPAGES]--;
 			}
+			rss[mm_counter(page)]--;
 			page_remove_rmap(page);
 			if (unlikely(page_mapcount(page) < 0))
 				print_bad_pte(vma, addr, ptent, page);

@@ -1146,11 +1139,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
 			struct page *page;
 
 			page = migration_entry_to_page(entry);
-
-			if (PageAnon(page))
-				rss[MM_ANONPAGES]--;
-			else
-				rss[MM_FILEPAGES]--;
+			rss[mm_counter(page)]--;
 		}
 		if (unlikely(!free_swap_and_cache(entry)))
 			print_bad_pte(vma, addr, ptent, NULL);

@@ -1460,7 +1449,7 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr,
 
 	/* Ok, finally just insert the thing.. */
 	get_page(page);
-	inc_mm_counter_fast(mm, MM_FILEPAGES);
+	inc_mm_counter_fast(mm, mm_counter_file(page));
 	page_add_file_rmap(page);
 	set_pte_at(mm, addr, pte, mk_pte(page, prot));

@@ -2097,7 +2086,8 @@ static int wp_page_copy(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (likely(pte_same(*page_table, orig_pte))) {
 		if (old_page) {
 			if (!PageAnon(old_page)) {
-				dec_mm_counter_fast(mm, MM_FILEPAGES);
+				dec_mm_counter_fast(mm,
+						mm_counter_file(old_page));
 				inc_mm_counter_fast(mm, MM_ANONPAGES);
 			}
 		} else {

@@ -2818,7 +2808,7 @@ void do_set_pte(struct vm_area_struct *vma, unsigned long address,
 		inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
 		page_add_new_anon_rmap(page, vma, address);
 	} else {
-		inc_mm_counter_fast(vma->vm_mm, MM_FILEPAGES);
+		inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page));
 		page_add_file_rmap(page);
 	}
 	set_pte_at(vma->vm_mm, address, pte, entry);

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 4766e25..127e2d6 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c

@@ -567,10 +567,11 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 	 */
 	do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true);
 	mark_oom_victim(victim);
-	pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n",
+	pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n",
 		task_pid_nr(victim), victim->comm, K(victim->mm->total_vm),
 		K(get_mm_counter(victim->mm, MM_ANONPAGES)),
-		K(get_mm_counter(victim->mm, MM_FILEPAGES)));
+		K(get_mm_counter(victim->mm, MM_FILEPAGES)),
+		K(get_mm_counter(victim->mm, MM_SHMEMPAGES)));
 	task_unlock(victim);
 
 	/*

diff --git a/mm/rmap.c b/mm/rmap.c
index 0ce371a..6c89356 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c

@@ -1383,10 +1383,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 		if (PageHuge(page)) {
 			hugetlb_count_sub(1 << compound_order(page), mm);
 		} else {
-			if (PageAnon(page))
-				dec_mm_counter(mm, MM_ANONPAGES);
-			else
-				dec_mm_counter(mm, MM_FILEPAGES);
+			dec_mm_counter(mm, mm_counter(page));
 		}
 		set_pte_at(mm, address, pte,
 			   swp_entry_to_pte(make_hwpoison_entry(page)));

@@ -1396,10 +1393,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 		 * interest anymore. Simply discard the pte, vmscan
 		 * will take care of the rest.
 		 */
-		if (PageAnon(page))
-			dec_mm_counter(mm, MM_ANONPAGES);
-		else
-			dec_mm_counter(mm, MM_FILEPAGES);
+		dec_mm_counter(mm, mm_counter(page));
 	} else if (PageAnon(page)) {
 		swp_entry_t entry = { .val = page_private(page) };
 		pte_t swp_pte;

@@ -1455,7 +1449,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 		entry = make_migration_entry(page, pte_write(pteval));
 		set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
 	} else
-		dec_mm_counter(mm, MM_FILEPAGES);
+		dec_mm_counter(mm, mm_counter_file(page));
 
 discard:
 	page_remove_rmap(page);

-- 
2.5.2

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