Hi Alan,
On 06 Aug 2001, Christoph Rohland wrote:
> Since there are enough persons having trouble with the current
> behaviour I append a patch (against 2.4.8-pre4) to implement the
> default to be ram/2.
The appended patch is the same against 2.4.7-ac7 plus some further
fixes/cleanups:
- Use PAGE_CACHE_SIZE consistently
- use info->sem instead of inode->i_sem where appropriate
- fix a race in shmem_lock
Greetings
Christoph
diff -uNr 7-ac7/mm/shmem.c 7-ac7-fix/mm/shmem.c
--- 7-ac7/mm/shmem.c Mon Aug 6 17:37:28 2001
+++ 7-ac7-fix/mm/shmem.c Mon Aug 6 18:06:13 2001
@@ -33,7 +33,7 @@
/* This magic number is used in glibc for posix shared memory */
#define TMPFS_MAGIC 0x01021994
-#define ENTRIES_PER_PAGE (PAGE_SIZE/sizeof(unsigned long))
+#define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long))
#define SHMEM_SB(sb) (&sb->u.shmem_sb)
@@ -49,7 +49,7 @@
static spinlock_t shmem_ilock = SPIN_LOCK_UNLOCKED;
atomic_t shmem_nrpages = ATOMIC_INIT(0);
-#define BLOCKS_PER_PAGE (PAGE_SIZE/512)
+#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
static void shmem_removepage(struct page *page)
{
@@ -626,7 +626,7 @@
unsigned int idx;
struct inode * inode = vma->vm_file->f_dentry->d_inode;
- idx = (address - vma->vm_start) >> PAGE_SHIFT;
+ idx = (address - vma->vm_start) >> PAGE_CACHE_SHIFT;
idx += vma->vm_pgoff;
if (shmem_getpage(inode, idx, &page))
@@ -655,9 +655,9 @@
struct page * page;
unsigned long idx, size;
- if (info->locked == lock)
- return;
- down(&inode->i_sem);
+ down(&info->sem);
+ if (info->locked == lock)
+ goto out;
info->locked = lock;
size = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
for (idx = 0; idx < size; idx++) {
@@ -671,7 +671,8 @@
}
UnlockPage(page);
}
- up(&inode->i_sem);
+out:
+ up(&info->sem);
}
static int shmem_mmap(struct file * file, struct vm_area_struct * vma)
@@ -962,18 +963,8 @@
buf->f_type = TMPFS_MAGIC;
buf->f_bsize = PAGE_CACHE_SIZE;
spin_lock (&sbinfo->stat_lock);
- if (sbinfo->max_blocks == ULONG_MAX) {
- /*
- * This is only a guestimate and not honoured.
- * We need it to make some programs happy which like to
- * test the free space of a file system.
- */
- buf->f_bavail = buf->f_bfree = nr_free_pages() + nr_swap_pages + atomic_read(&buffermem_pages);
- buf->f_blocks = buf->f_bfree + ULONG_MAX - sbinfo->free_blocks;
- } else {
- buf->f_blocks = sbinfo->max_blocks;
- buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
- }
+ buf->f_blocks = sbinfo->max_blocks;
+ buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
buf->f_files = sbinfo->max_inodes;
buf->f_ffree = sbinfo->free_inodes;
spin_unlock (&sbinfo->stat_lock);
@@ -1129,7 +1120,7 @@
return error;
len = strlen(symname) + 1;
- if (len > PAGE_SIZE)
+ if (len > PAGE_CACHE_SIZE)
return -ENAMETOOLONG;
inode = dentry->d_inode;
@@ -1143,10 +1134,10 @@
spin_lock (&shmem_ilock);
list_add (&info->list, &shmem_inodes);
spin_unlock (&shmem_ilock);
- down(&inode->i_sem);
+ down(&info->sem);
page = shmem_getpage_locked(info, inode, 0);
if (IS_ERR(page)) {
- up(&inode->i_sem);
+ up(&info->sem);
return PTR_ERR(page);
}
kaddr = kmap(page);
@@ -1155,7 +1146,7 @@
SetPageDirty(page);
UnlockPage(page);
page_cache_release(page);
- up(&inode->i_sem);
+ up(&info->sem);
inode->i_op = &shmem_symlink_inode_operations;
}
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
@@ -1253,17 +1244,11 @@
return 0;
}
-static int shmem_remount_fs (struct super_block *sb, int *flags, char *data)
+static int shmem_set_size(struct shmem_sb_info *sbinfo,
+ unsigned long max_blocks, unsigned long max_inodes)
{
int error;
- unsigned long max_blocks, blocks;
- unsigned long max_inodes, inodes;
- struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
-
- max_blocks = sbinfo->max_blocks;
- max_inodes = sbinfo->max_inodes;
- if (shmem_parse_options (data, NULL, &max_blocks, &max_inodes))
- return -EINVAL;
+ unsigned long blocks, inodes;
spin_lock(&sbinfo->stat_lock);
blocks = sbinfo->max_blocks - sbinfo->free_blocks;
@@ -1283,6 +1268,17 @@
return error;
}
+static int shmem_remount_fs (struct super_block *sb, int *flags, char *data)
+{
+ struct shmem_sb_info *sbinfo = &sb->u.shmem_sb;
+ unsigned long max_blocks = sbinfo->max_blocks;
+ unsigned long max_inodes = sbinfo->max_inodes;
+
+ if (shmem_parse_options (data, NULL, &max_blocks, &max_inodes))
+ return -EINVAL;
+ return shmem_set_size(sbinfo, max_blocks, max_inodes);
+}
+
int shmem_sync_file(struct file * file, struct dentry *dentry, int datasync)
{
return 0;
@@ -1293,10 +1289,17 @@
{
struct inode * inode;
struct dentry * root;
- unsigned long blocks = ULONG_MAX; /* unlimited */
- unsigned long inodes = ULONG_MAX; /* unlimited */
+ unsigned long blocks, inodes;
int mode = S_IRWXUGO | S_ISVTX;
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
+ struct sysinfo si;
+
+ /*
+ * Per default we only allow half of the physical ram per
+ * tmpfs instance
+ */
+ si_meminfo(&si);
+ blocks = inodes = si.totalram / 2;
#ifdef CONFIG_TMPFS
if (shmem_parse_options (data, &mode, &blocks, &inodes)) {
@@ -1416,6 +1419,10 @@
}
shm_mnt = res;
+ /* The internal instance should not do size checking */
+ if ((error = shmem_set_size(SHMEM_SB(res->mnt_sb), ULONG_MAX, ULONG_MAX)))
+ printk (KERN_ERR "could not set limits on internal tmpfs\n");
+
return 0;
}
@@ -1450,7 +1457,7 @@
if (size > (unsigned long long) SHMEM_MAX_BLOCKS << PAGE_CACHE_SHIFT)
return ERR_PTR(-EINVAL);
- if (!vm_enough_memory((size) >> PAGE_SHIFT))
+ if (!vm_enough_memory((size) >> PAGE_CACHE_SHIFT))
return ERR_PTR(-ENOMEM);
this.name = name;
-
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This archive was generated by hypermail 2b29 : Tue Aug 07 2001 - 21:00:39 EST