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authorHugh Dickins <hugh@veritas.com>2009-02-24 15:51:52 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2009-02-25 15:21:42 -0500
commit0b0a0806b0d8635e046bf533225a25903b1cddce (patch)
tree245ac39eb1b7c6008a669ab2d68ed174d66bd7bc /mm/shmem.c
parentc15d8a6499d04e5d2cac07f8120f207bb275f60f (diff)
shmem: fix shared anonymous accounting
Each time I exit Firefox, /proc/meminfo's Committed_AS goes down almost 400 kB: OVERCOMMIT_NEVER would be allowing overcommits it should prohibit. Commit fc8744adc870a8d4366908221508bb113d8b72ee "Stop playing silly games with the VM_ACCOUNT flag" changed shmem_file_setup() to set the shmem file's VM_ACCOUNT flag according to VM_NORESERVE not being set in the vma flags; but did so only _after_ the shmem_acct_size(flags, size) call which is expected to pre-account a shared anonymous object. It's all clearer if we switch shmem.c over to use VM_NORESERVE throughout in place of !VM_ACCOUNT. But I very nearly sent in a patch which mistakenly removed the accounting from tmpfs files: shmem_get_inode()'s memset was good for not setting VM_ACCOUNT, but now it needs to set VM_NORESERVE. Rather than setting that by default, then perhaps clearing it again in shmem_file_setup(), let's pass it as a flag to shmem_get_inode(): that allows us to remove the #ifdef CONFIG_SHMEM from shmem_file_setup(). Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/shmem.c')
-rw-r--r--mm/shmem.c43
1 files changed, 21 insertions, 22 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 19d566ccdee..4103a239ce8 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -169,13 +169,13 @@ static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
169 */ 169 */
170static inline int shmem_acct_size(unsigned long flags, loff_t size) 170static inline int shmem_acct_size(unsigned long flags, loff_t size)
171{ 171{
172 return (flags & VM_ACCOUNT) ? 172 return (flags & VM_NORESERVE) ?
173 security_vm_enough_memory_kern(VM_ACCT(size)) : 0; 173 0 : security_vm_enough_memory_kern(VM_ACCT(size));
174} 174}
175 175
176static inline void shmem_unacct_size(unsigned long flags, loff_t size) 176static inline void shmem_unacct_size(unsigned long flags, loff_t size)
177{ 177{
178 if (flags & VM_ACCOUNT) 178 if (!(flags & VM_NORESERVE))
179 vm_unacct_memory(VM_ACCT(size)); 179 vm_unacct_memory(VM_ACCT(size));
180} 180}
181 181
@@ -187,13 +187,13 @@ static inline void shmem_unacct_size(unsigned long flags, loff_t size)
187 */ 187 */
188static inline int shmem_acct_block(unsigned long flags) 188static inline int shmem_acct_block(unsigned long flags)
189{ 189{
190 return (flags & VM_ACCOUNT) ? 190 return (flags & VM_NORESERVE) ?
191 0 : security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)); 191 security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0;
192} 192}
193 193
194static inline void shmem_unacct_blocks(unsigned long flags, long pages) 194static inline void shmem_unacct_blocks(unsigned long flags, long pages)
195{ 195{
196 if (!(flags & VM_ACCOUNT)) 196 if (flags & VM_NORESERVE)
197 vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); 197 vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE));
198} 198}
199 199
@@ -1515,8 +1515,8 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
1515 return 0; 1515 return 0;
1516} 1516}
1517 1517
1518static struct inode * 1518static struct inode *shmem_get_inode(struct super_block *sb, int mode,
1519shmem_get_inode(struct super_block *sb, int mode, dev_t dev) 1519 dev_t dev, unsigned long flags)
1520{ 1520{
1521 struct inode *inode; 1521 struct inode *inode;
1522 struct shmem_inode_info *info; 1522 struct shmem_inode_info *info;
@@ -1537,6 +1537,7 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
1537 info = SHMEM_I(inode); 1537 info = SHMEM_I(inode);
1538 memset(info, 0, (char *)inode - (char *)info); 1538 memset(info, 0, (char *)inode - (char *)info);
1539 spin_lock_init(&info->lock); 1539 spin_lock_init(&info->lock);
1540 info->flags = flags & VM_NORESERVE;
1540 INIT_LIST_HEAD(&info->swaplist); 1541 INIT_LIST_HEAD(&info->swaplist);
1541 1542
1542 switch (mode & S_IFMT) { 1543 switch (mode & S_IFMT) {
@@ -1779,9 +1780,10 @@ static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
1779static int 1780static int
1780shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 1781shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
1781{ 1782{
1782 struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); 1783 struct inode *inode;
1783 int error = -ENOSPC; 1784 int error = -ENOSPC;
1784 1785
1786 inode = shmem_get_inode(dir->i_sb, mode, dev, VM_NORESERVE);
1785 if (inode) { 1787 if (inode) {
1786 error = security_inode_init_security(inode, dir, NULL, NULL, 1788 error = security_inode_init_security(inode, dir, NULL, NULL,
1787 NULL); 1789 NULL);
@@ -1920,7 +1922,7 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
1920 if (len > PAGE_CACHE_SIZE) 1922 if (len > PAGE_CACHE_SIZE)
1921 return -ENAMETOOLONG; 1923 return -ENAMETOOLONG;
1922 1924
1923 inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); 1925 inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE);
1924 if (!inode) 1926 if (!inode)
1925 return -ENOSPC; 1927 return -ENOSPC;
1926 1928
@@ -2332,7 +2334,7 @@ static int shmem_fill_super(struct super_block *sb,
2332 sb->s_flags |= MS_POSIXACL; 2334 sb->s_flags |= MS_POSIXACL;
2333#endif 2335#endif
2334 2336
2335 inode = shmem_get_inode(sb, S_IFDIR | sbinfo->mode, 0); 2337 inode = shmem_get_inode(sb, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE);
2336 if (!inode) 2338 if (!inode)
2337 goto failed; 2339 goto failed;
2338 inode->i_uid = sbinfo->uid; 2340 inode->i_uid = sbinfo->uid;
@@ -2574,12 +2576,12 @@ int shmem_unuse(swp_entry_t entry, struct page *page)
2574 return 0; 2576 return 0;
2575} 2577}
2576 2578
2577#define shmem_file_operations ramfs_file_operations 2579#define shmem_vm_ops generic_file_vm_ops
2578#define shmem_vm_ops generic_file_vm_ops 2580#define shmem_file_operations ramfs_file_operations
2579#define shmem_get_inode ramfs_get_inode 2581#define shmem_get_inode(sb, mode, dev, flags) ramfs_get_inode(sb, mode, dev)
2580#define shmem_acct_size(a, b) 0 2582#define shmem_acct_size(flags, size) 0
2581#define shmem_unacct_size(a, b) do {} while (0) 2583#define shmem_unacct_size(flags, size) do {} while (0)
2582#define SHMEM_MAX_BYTES LLONG_MAX 2584#define SHMEM_MAX_BYTES LLONG_MAX
2583 2585
2584#endif /* CONFIG_SHMEM */ 2586#endif /* CONFIG_SHMEM */
2585 2587
@@ -2589,7 +2591,7 @@ int shmem_unuse(swp_entry_t entry, struct page *page)
2589 * shmem_file_setup - get an unlinked file living in tmpfs 2591 * shmem_file_setup - get an unlinked file living in tmpfs
2590 * @name: name for dentry (to be seen in /proc/<pid>/maps 2592 * @name: name for dentry (to be seen in /proc/<pid>/maps
2591 * @size: size to be set for the file 2593 * @size: size to be set for the file
2592 * @flags: vm_flags 2594 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
2593 */ 2595 */
2594struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) 2596struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
2595{ 2597{
@@ -2623,13 +2625,10 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
2623 goto put_dentry; 2625 goto put_dentry;
2624 2626
2625 error = -ENOSPC; 2627 error = -ENOSPC;
2626 inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); 2628 inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0, flags);
2627 if (!inode) 2629 if (!inode)
2628 goto close_file; 2630 goto close_file;
2629 2631
2630#ifdef CONFIG_SHMEM
2631 SHMEM_I(inode)->flags = (flags & VM_NORESERVE) ? 0 : VM_ACCOUNT;
2632#endif
2633 d_instantiate(dentry, inode); 2632 d_instantiate(dentry, inode);
2634 inode->i_size = size; 2633 inode->i_size = size;
2635 inode->i_nlink = 0; /* It is unlinked */ 2634 inode->i_nlink = 0; /* It is unlinked */