proc: switch /proc/meminfo to seq_file

and move it to fs/proc/meminfo.c while I'm at it.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>

arch/x86/mm/pageattr.c

@@ -65,23 +65,22 @@ static void split_page_count(int level)
 	direct_pages_count[level - 1] += PTRS_PER_PTE;
 }
 
-int arch_report_meminfo(char *page)
+void arch_report_meminfo(struct seq_file *m)
 {
-	int n = sprintf(page, "DirectMap4k:  %8lu kB\n",
+	seq_printf(m, "DirectMap4k:  %8lu kB\n",
 			direct_pages_count[PG_LEVEL_4K] << 2);
 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
-	n += sprintf(page + n, "DirectMap2M:  %8lu kB\n",
+	seq_printf(m, "DirectMap2M:  %8lu kB\n",
 			direct_pages_count[PG_LEVEL_2M] << 11);
 #else
-	n += sprintf(page + n, "DirectMap4M:  %8lu kB\n",
+	seq_printf(m, "DirectMap4M:  %8lu kB\n",
 			direct_pages_count[PG_LEVEL_2M] << 12);
 #endif
 #ifdef CONFIG_X86_64
 	if (direct_gbpages)
-		n += sprintf(page + n, "DirectMap1G:  %8lu kB\n",
+		seq_printf(m, "DirectMap1G:  %8lu kB\n",
 			direct_pages_count[PG_LEVEL_1G] << 20);
 #endif
-	return n;
 }
 #else
 static inline void split_page_count(int level) { }

fs/proc/Makefile

@@ -10,6 +10,7 @@ proc-$(CONFIG_MMU)	:= mmu.o task_mmu.o
 proc-y       += inode.o root.o base.o generic.o array.o \
 		proc_tty.o proc_misc.o
 proc-y	+= loadavg.o
+proc-y	+= meminfo.o
 proc-y	+= uptime.o
 proc-$(CONFIG_PROC_SYSCTL)	+= proc_sysctl.o
 proc-$(CONFIG_NET)		+= proc_net.o

fs/proc/meminfo.c

+#include <linux/fs.h>
+#include <linux/hugetlb.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/mmzone.h>
+#include <linux/proc_fs.h>
+#include <linux/quicklist.h>
+#include <linux/seq_file.h>
+#include <linux/swap.h>
+#include <linux/vmstat.h>
+#include <asm/atomic.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include "internal.h"
+
+void __attribute__((weak)) arch_report_meminfo(struct seq_file *m)
+{
+}
+
+static int meminfo_proc_show(struct seq_file *m, void *v)
+{
+	struct sysinfo i;
+	unsigned long committed;
+	unsigned long allowed;
+	struct vmalloc_info vmi;
+	long cached;
+	unsigned long pages[NR_LRU_LISTS];
+	int lru;
+
+/*
+ * display in kilobytes.
+ */
+#define K(x) ((x) << (PAGE_SHIFT - 10))
+	si_meminfo(&i);
+	si_swapinfo(&i);
+	committed = atomic_long_read(&vm_committed_space);
+	allowed = ((totalram_pages - hugetlb_total_pages())
+		* sysctl_overcommit_ratio / 100) + total_swap_pages;
+
+	cached = global_page_state(NR_FILE_PAGES) -
+			total_swapcache_pages - i.bufferram;
+	if (cached < 0)
+		cached = 0;
+
+	get_vmalloc_info(&vmi);
+
+	for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
+		pages[lru] = global_page_state(NR_LRU_BASE + lru);
+
+	/*
+	 * Tagged format, for easy grepping and expansion.
+	 */
+	seq_printf(m,
+		"MemTotal:       %8lu kB\n"
+		"MemFree:        %8lu kB\n"
+		"Buffers:        %8lu kB\n"
+		"Cached:         %8lu kB\n"
+		"SwapCached:     %8lu kB\n"
+		"Active:         %8lu kB\n"
+		"Inactive:       %8lu kB\n"
+		"Active(anon):   %8lu kB\n"
+		"Inactive(anon): %8lu kB\n"
+		"Active(file):   %8lu kB\n"
+		"Inactive(file): %8lu kB\n"
+#ifdef CONFIG_UNEVICTABLE_LRU
+		"Unevictable:    %8lu kB\n"
+		"Mlocked:        %8lu kB\n"
+#endif
+#ifdef CONFIG_HIGHMEM
+		"HighTotal:      %8lu kB\n"
+		"HighFree:       %8lu kB\n"
+		"LowTotal:       %8lu kB\n"
+		"LowFree:        %8lu kB\n"
+#endif
+		"SwapTotal:      %8lu kB\n"
+		"SwapFree:       %8lu kB\n"
+		"Dirty:          %8lu kB\n"
+		"Writeback:      %8lu kB\n"
+		"AnonPages:      %8lu kB\n"
+		"Mapped:         %8lu kB\n"
+		"Slab:           %8lu kB\n"
+		"SReclaimable:   %8lu kB\n"
+		"SUnreclaim:     %8lu kB\n"
+		"PageTables:     %8lu kB\n"
+#ifdef CONFIG_QUICKLIST
+		"Quicklists:     %8lu kB\n"
+#endif
+		"NFS_Unstable:   %8lu kB\n"
+		"Bounce:         %8lu kB\n"
+		"WritebackTmp:   %8lu kB\n"
+		"CommitLimit:    %8lu kB\n"
+		"Committed_AS:   %8lu kB\n"
+		"VmallocTotal:   %8lu kB\n"
+		"VmallocUsed:    %8lu kB\n"
+		"VmallocChunk:   %8lu kB\n",
+		K(i.totalram),
+		K(i.freeram),
+		K(i.bufferram),
+		K(cached),
+		K(total_swapcache_pages),
+		K(pages[LRU_ACTIVE_ANON]   + pages[LRU_ACTIVE_FILE]),
+		K(pages[LRU_INACTIVE_ANON] + pages[LRU_INACTIVE_FILE]),
+		K(pages[LRU_ACTIVE_ANON]),
+		K(pages[LRU_INACTIVE_ANON]),
+		K(pages[LRU_ACTIVE_FILE]),
+		K(pages[LRU_INACTIVE_FILE]),
+#ifdef CONFIG_UNEVICTABLE_LRU
+		K(pages[LRU_UNEVICTABLE]),
+		K(global_page_state(NR_MLOCK)),
+#endif
+#ifdef CONFIG_HIGHMEM
+		K(i.totalhigh),
+		K(i.freehigh),
+		K(i.totalram-i.totalhigh),
+		K(i.freeram-i.freehigh),
+#endif
+		K(i.totalswap),
+		K(i.freeswap),
+		K(global_page_state(NR_FILE_DIRTY)),
+		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_SLAB_RECLAIMABLE) +
+				global_page_state(NR_SLAB_UNRECLAIMABLE)),
+		K(global_page_state(NR_SLAB_RECLAIMABLE)),
+		K(global_page_state(NR_SLAB_UNRECLAIMABLE)),
+		K(global_page_state(NR_PAGETABLE)),
+#ifdef CONFIG_QUICKLIST
+		K(quicklist_total_size()),
+#endif
+		K(global_page_state(NR_UNSTABLE_NFS)),
+		K(global_page_state(NR_BOUNCE)),
+		K(global_page_state(NR_WRITEBACK_TEMP)),
+		K(allowed),
+		K(committed),
+		(unsigned long)VMALLOC_TOTAL >> 10,
+		vmi.used >> 10,
+		vmi.largest_chunk >> 10
+		);
+
+	hugetlb_report_meminfo(m);
+
+	arch_report_meminfo(m);
+
+	return 0;
+#undef K
+}
+
+static int meminfo_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, meminfo_proc_show, NULL);
+}
+
+static const struct file_operations meminfo_proc_fops = {
+	.open		= meminfo_proc_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init proc_meminfo_init(void)
+{
+	proc_create("meminfo", 0, NULL, &meminfo_proc_fops);
+	return 0;
+}
+module_init(proc_meminfo_init);

fs/proc/proc_misc.c

@@ -78,142 +78,6 @@ static int proc_calc_metrics(char *page, char **start, off_t off,
 	return len;
 }
 
-int __attribute__((weak)) arch_report_meminfo(char *page)
-{
-	return 0;
-}
-
-static int meminfo_read_proc(char *page, char **start, off_t off,
-				 int count, int *eof, void *data)
-{
-	struct sysinfo i;
-	int len;
-	unsigned long committed;
-	unsigned long allowed;
-	struct vmalloc_info vmi;
-	long cached;
-	unsigned long pages[NR_LRU_LISTS];
-	int lru;
-
-/*
- * display in kilobytes.
- */
-#define K(x) ((x) << (PAGE_SHIFT - 10))
-	si_meminfo(&i);
-	si_swapinfo(&i);
-	committed = atomic_long_read(&vm_committed_space);
-	allowed = ((totalram_pages - hugetlb_total_pages())
-		* sysctl_overcommit_ratio / 100) + total_swap_pages;
-
-	cached = global_page_state(NR_FILE_PAGES) -
-			total_swapcache_pages - i.bufferram;
-	if (cached < 0)
-		cached = 0;
-
-	get_vmalloc_info(&vmi);
-
-	for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
-		pages[lru] = global_page_state(NR_LRU_BASE + lru);
-
-	/*
-	 * Tagged format, for easy grepping and expansion.
-	 */
-	len = sprintf(page,
-		"MemTotal:       %8lu kB\n"
-		"MemFree:        %8lu kB\n"
-		"Buffers:        %8lu kB\n"
-		"Cached:         %8lu kB\n"
-		"SwapCached:     %8lu kB\n"
-		"Active:         %8lu kB\n"
-		"Inactive:       %8lu kB\n"
-		"Active(anon):   %8lu kB\n"
-		"Inactive(anon): %8lu kB\n"
-		"Active(file):   %8lu kB\n"
-		"Inactive(file): %8lu kB\n"
-#ifdef CONFIG_UNEVICTABLE_LRU
-		"Unevictable:    %8lu kB\n"
-		"Mlocked:        %8lu kB\n"
-#endif
-#ifdef CONFIG_HIGHMEM
-		"HighTotal:      %8lu kB\n"
-		"HighFree:       %8lu kB\n"
-		"LowTotal:       %8lu kB\n"
-		"LowFree:        %8lu kB\n"
-#endif
-		"SwapTotal:      %8lu kB\n"
-		"SwapFree:       %8lu kB\n"
-		"Dirty:          %8lu kB\n"
-		"Writeback:      %8lu kB\n"
-		"AnonPages:      %8lu kB\n"
-		"Mapped:         %8lu kB\n"
-		"Slab:           %8lu kB\n"
-		"SReclaimable:   %8lu kB\n"
-		"SUnreclaim:     %8lu kB\n"
-		"PageTables:     %8lu kB\n"
-#ifdef CONFIG_QUICKLIST
-		"Quicklists:     %8lu kB\n"
-#endif
-		"NFS_Unstable:   %8lu kB\n"
-		"Bounce:         %8lu kB\n"
-		"WritebackTmp:   %8lu kB\n"
-		"CommitLimit:    %8lu kB\n"
-		"Committed_AS:   %8lu kB\n"
-		"VmallocTotal:   %8lu kB\n"
-		"VmallocUsed:    %8lu kB\n"
-		"VmallocChunk:   %8lu kB\n",
-		K(i.totalram),
-		K(i.freeram),
-		K(i.bufferram),
-		K(cached),
-		K(total_swapcache_pages),
-		K(pages[LRU_ACTIVE_ANON]   + pages[LRU_ACTIVE_FILE]),
-		K(pages[LRU_INACTIVE_ANON] + pages[LRU_INACTIVE_FILE]),
-		K(pages[LRU_ACTIVE_ANON]),
-		K(pages[LRU_INACTIVE_ANON]),
-		K(pages[LRU_ACTIVE_FILE]),
-		K(pages[LRU_INACTIVE_FILE]),
-#ifdef CONFIG_UNEVICTABLE_LRU
-		K(pages[LRU_UNEVICTABLE]),
-		K(global_page_state(NR_MLOCK)),
-#endif
-#ifdef CONFIG_HIGHMEM
-		K(i.totalhigh),
-		K(i.freehigh),
-		K(i.totalram-i.totalhigh),
-		K(i.freeram-i.freehigh),
-#endif
-		K(i.totalswap),
-		K(i.freeswap),
-		K(global_page_state(NR_FILE_DIRTY)),
-		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_SLAB_RECLAIMABLE) +
-				global_page_state(NR_SLAB_UNRECLAIMABLE)),
-		K(global_page_state(NR_SLAB_RECLAIMABLE)),
-		K(global_page_state(NR_SLAB_UNRECLAIMABLE)),
-		K(global_page_state(NR_PAGETABLE)),
-#ifdef CONFIG_QUICKLIST
-		K(quicklist_total_size()),
-#endif
-		K(global_page_state(NR_UNSTABLE_NFS)),
-		K(global_page_state(NR_BOUNCE)),
-		K(global_page_state(NR_WRITEBACK_TEMP)),
-		K(allowed),
-		K(committed),
-		(unsigned long)VMALLOC_TOTAL >> 10,
-		vmi.used >> 10,
-		vmi.largest_chunk >> 10
-		);
-
-		len += hugetlb_report_meminfo(page + len);
-
-	len += arch_report_meminfo(page + len);
-
-	return proc_calc_metrics(page, start, off, count, eof, len);
-#undef K
-}
-
 static int fragmentation_open(struct inode *inode, struct file *file)
 {
 	(void)inode;
@@ -816,7 +680,6 @@ void __init proc_misc_init(void)
 		char *name;
 		int (*read_proc)(char*,char**,off_t,int,int*,void*);
 	} *p, simple_ones[] = {
-		{"meminfo",	meminfo_read_proc},
 		{"version",	version_read_proc},
 #ifdef CONFIG_PROC_HARDWARE
 		{"hardware",	hardware_read_proc},

include/asm-x86/pgtable.h

@@ -348,7 +348,8 @@ static inline void native_pagetable_setup_start(pgd_t *base) {}
 static inline void native_pagetable_setup_done(pgd_t *base) {}
 #endif
 
-extern int arch_report_meminfo(char *page);
+struct seq_file;
+extern void arch_report_meminfo(struct seq_file *m);
 
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>

include/linux/hugetlb.h

@@ -27,7 +27,7 @@ void unmap_hugepage_range(struct vm_area_struct *,
 void __unmap_hugepage_range(struct vm_area_struct *,
 			unsigned long, unsigned long, struct page *);
 int hugetlb_prefault(struct address_space *, struct vm_area_struct *);
-int hugetlb_report_meminfo(char *);
+void hugetlb_report_meminfo(struct seq_file *);
 int hugetlb_report_node_meminfo(int, char *);
 unsigned long hugetlb_total_pages(void);
 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
@@ -79,7 +79,9 @@ static inline unsigned long hugetlb_total_pages(void)
 #define copy_hugetlb_page_range(src, dst, vma)	({ BUG(); 0; })
 #define hugetlb_prefault(mapping, vma)		({ BUG(); 0; })
 #define unmap_hugepage_range(vma, start, end, page)	BUG()
-#define hugetlb_report_meminfo(buf)		0
+static inline void hugetlb_report_meminfo(struct seq_file *m)
+{
+}
 #define hugetlb_report_node_meminfo(n, buf)	0
 #define follow_huge_pmd(mm, addr, pmd, write)	NULL
 #define follow_huge_pud(mm, addr, pud, write)	NULL

mm/hugetlb.c

@@ -7,6 +7,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/mm.h>
+#include <linux/seq_file.h>
 #include <linux/sysctl.h>
 #include <linux/highmem.h>
 #include <linux/mmu_notifier.h>
@@ -1455,10 +1456,10 @@ int hugetlb_overcommit_handler(struct ctl_table *table, int write,
 
 #endif /* CONFIG_SYSCTL */
 
-int hugetlb_report_meminfo(char *buf)
+void hugetlb_report_meminfo(struct seq_file *m)
 {
 	struct hstate *h = &default_hstate;
-	return sprintf(buf,
+	seq_printf(m,
 			"HugePages_Total:   %5lu\n"
 			"HugePages_Free:    %5lu\n"
 			"HugePages_Rsvd:    %5lu\n"