Repeated overnight kernel builds in tmpfs showed insane Committed_AS
by morning. The main bug was that shmem_file_write was passing
(newsize-oldsize)>>PAGE_SHIFT to vm_enough_memory, but it has to be
((newsize>>PAGE_SHIFT)-(oldsize>>PAGE_SHIFT)) - imagine 1k writes.
But actually, if we're going to do strict accounting, then we should
round up to next page not down - use VM_ACCT macro throughout (needs
unusual mix of PAGE_CACHE_SIZE with PAGE_SHIFT); and must count one
page for a long symlink.
--- 2.5.29-1.523/mm/shmem.c Mon Jul 29 11:48:04 2002
+++ vmacct1/mm/shmem.c Mon Jul 29 19:23:46 2002
@@ -38,6 +38,8 @@
#define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long))
+#define VM_ACCT(size) (((size) + PAGE_CACHE_SIZE - 1) >> PAGE_SHIFT)
+
static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
{
return sb->u.generic_sbp;
@@ -371,10 +373,8 @@
*/
long change;
- change = ((attr->ia_size + PAGE_SIZE - 1) >> PAGE_SHIFT) -
- ((inode->i_size + PAGE_SIZE - 1 ) >> PAGE_SHIFT);
-
- if (attr->ia_size > inode->i_size) {
+ change = VM_ACCT(attr->ia_size) - VM_ACCT(inode->i_size);
+ if (change > 0) {
if (!vm_enough_memory(change))
return -ENOMEM;
} else
@@ -393,13 +393,12 @@
{
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
- vm_unacct_memory((inode->i_size) >> PAGE_SHIFT);
-
- inode->i_size = 0;
- if (inode->i_op->truncate == shmem_truncate){
+ if (inode->i_op->truncate == shmem_truncate) {
spin_lock (&shmem_ilock);
list_del (&SHMEM_I(inode)->list);
spin_unlock (&shmem_ilock);
+ vm_unacct_memory(VM_ACCT(inode->i_size));
+ inode->i_size = 0;
shmem_truncate (inode);
}
spin_lock (&sbinfo->stat_lock);
@@ -886,7 +885,7 @@
maxpos = inode->i_size;
if (pos + count > inode->i_size) {
maxpos = pos + count;
- if (!vm_enough_memory((maxpos - inode->i_size) >> PAGE_SHIFT)) {
+ if (!vm_enough_memory(VM_ACCT(maxpos) - VM_ACCT(inode->i_size))) {
err = -ENOMEM;
goto out_nc;
}
@@ -983,7 +982,7 @@
out:
/* Short writes give back address space */
if (inode->i_size != maxpos)
- vm_unacct_memory((maxpos - inode->i_size) >> PAGE_SHIFT);
+ vm_unacct_memory(VM_ACCT(maxpos) - VM_ACCT(inode->i_size));
out_nc:
up(&inode->i_sem);
return err;
@@ -1238,10 +1237,15 @@
memcpy(info, symname, len);
inode->i_op = &shmem_symlink_inline_operations;
} else {
+ if (!vm_enough_memory(VM_ACCT(1))) {
+ iput(inode);
+ return -ENOMEM;
+ }
down(&info->sem);
page = shmem_getpage_locked(info, inode, 0);
if (IS_ERR(page)) {
up(&info->sem);
+ vm_unacct_memory(VM_ACCT(1));
iput(inode);
return PTR_ERR(page);
}
@@ -1648,7 +1652,7 @@
*/
struct file *shmem_file_setup(char * name, loff_t size)
{
- int error = -ENOMEM;
+ int error;
struct file *file;
struct inode * inode;
struct dentry *dentry, *root;
@@ -1657,9 +1661,10 @@
if (size > (unsigned long long) SHMEM_MAX_BLOCKS << PAGE_CACHE_SHIFT)
return ERR_PTR(-EINVAL);
- if (!vm_enough_memory((size) >> PAGE_CACHE_SHIFT))
+ if (!vm_enough_memory(VM_ACCT(size)))
return ERR_PTR(-ENOMEM);
+ error = -ENOMEM;
this.name = name;
this.len = strlen(name);
this.hash = 0; /* will go */
@@ -1693,9 +1698,10 @@
put_dentry:
dput (dentry);
put_memory:
- vm_unacct_memory((size) >> PAGE_CACHE_SHIFT);
+ vm_unacct_memory(VM_ACCT(size));
return ERR_PTR(error);
}
+
/*
* shmem_zero_setup - setup a shared anonymous mapping
*
-
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This archive was generated by hypermail 2b29 : Tue Jul 30 2002 - 14:00:34 EST