mm: export NR_SHMEM via sysinfo(2) / si_meminfo() interfaces (cc7452b6) · Commits · 戴 / test

Historically, we exported shared pages to userspace via sysinfo(2) sharedram and /proc/meminfo's "MemShared" fields. With the advent of tmpfs, from kernel v2.4 onward, that old way for accounting shared mem was deemed inaccurate and we started to export a hard-coded 0 for sysinfo.sharedram. Later on, during the 2.6 timeframe, "MemShared" got re-introduced to /proc/meminfo re-branded as "Shmem", but we're still reporting sysinfo.sharedmem as that old hard-coded zero, which makes the "shared memory" report inconsistent across interfaces. This patch leverages the addition of explicit accounting for pages used by shmem/tmpfs -- " mm: oom analysis: add shmem vmstat" -- in order to make the users of sysinfo(2) and si_meminfo*() friends aware of that vmstat entry and make them report it consistently across the interfaces, as well to make sysinfo(2) returned data consistent with our current API documentation states. Signed-off-by:

Rafael Aquini <aquini@redhat.com> Acked-by:

Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

drivers/base/node.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -126,7 +126,7 @@ static ssize_t node_read_meminfo(struct device *dev,
		nid, K(node_page_state(nid, NR_FILE_PAGES)),
		nid, K(node_page_state(nid, NR_FILE_MAPPED)),
		nid, K(node_page_state(nid, NR_ANON_PAGES)),
		nid, K(node_page_state(nid, NR_SHMEM)),
		nid, K(i.sharedram),
		nid, node_page_state(nid, NR_KERNEL_STACK) *
		THREAD_SIZE / 1024,
		nid, K(node_page_state(nid, NR_PAGETABLE)),

fs/proc/meminfo.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -168,7 +168,7 @@ static int meminfo_proc_show(struct seq_file m, void v)
		K(global_page_state(NR_WRITEBACK)),
		K(global_page_state(NR_ANON_PAGES)),
		K(global_page_state(NR_FILE_MAPPED)),
		K(global_page_state(NR_SHMEM)),
		K(i.sharedram),
		K(global_page_state(NR_SLAB_RECLAIMABLE) +
		global_page_state(NR_SLAB_UNRECLAIMABLE)),
		K(global_page_state(NR_SLAB_RECLAIMABLE)),

mm/page_alloc.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -3047,7 +3047,7 @@ static inline void show_node(struct zone *zone)
		void si_meminfo(struct sysinfo *val)
		{
		val->totalram = totalram_pages;
		val->sharedram = 0;
		val->sharedram = global_page_state(NR_SHMEM);
		val->freeram = global_page_state(NR_FREE_PAGES);
		val->bufferram = nr_blockdev_pages();
		val->totalhigh = totalhigh_pages;
		@@ -3067,6 +3067,7 @@ void si_meminfo_node(struct sysinfo *val, int nid)
		for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
		managed_pages += pgdat->node_zones[zone_type].managed_pages;
		val->totalram = managed_pages;
		val->sharedram = node_page_state(nid, NR_SHMEM);
		val->freeram = node_page_state(nid, NR_FREE_PAGES);
		#ifdef CONFIG_HIGHMEM
		val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].managed_pages;

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