From: Christoph Rohland <cr@sap.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [Patch] tmpfs accounting cleanup for -ac series
Date: 17 May 2001 17:02:06 +0200 [thread overview]
Message-ID: <m3itj0t3wx.fsf@linux.local> (raw)
Hi Alan,
While looking at the -ac version of ramfs I noticed that there is a
new address operation introduced which I can use to cleanup shmem.
This patch throws away some magic recalculation and makes the
accounting of shmem accurate.
It also encapsulates all accesses to the superblock_info into a macro.
The patch is on top of my previous ones.
Greetings
Christoph
diff -uNr 4-ac9/fs/proc/proc_misc.c c/fs/proc/proc_misc.c
--- 4-ac9/fs/proc/proc_misc.c Thu May 17 13:17:37 2001
+++ c/fs/proc/proc_misc.c Thu May 17 13:11:30 2001
@@ -140,17 +140,9 @@
{
struct sysinfo i;
int len;
- unsigned int cached, shmem;
+ unsigned int cached;
- /*
- * There may be some inconsistency because shmem_nrpages
- * update is delayed to page_cache_size
- * We make sure the cached value does not get below zero
- */
- cached = atomic_read(&page_cache_size);
- shmem = atomic_read(&shmem_nrpages);
- if (shmem < cached)
- cached -= shmem;
+ cached = atomic_read(&page_cache_size) - atomic_read(&shmem_nrpages);
/*
* display in kilobytes.
diff -uNr 4-ac9/mm/mmap.c c/mm/mmap.c
--- 4-ac9/mm/mmap.c Thu May 17 13:17:37 2001
+++ c/mm/mmap.c Thu May 17 10:54:22 2001
@@ -56,24 +56,14 @@
*/
long free;
- unsigned long cached, shmem;
-
- /*
- * There may be some inconsistency because shmem_nrpages
- * update is delayed to the page_cache_size
- * We make sure the cached value does not get below zero
- */
- cached = atomic_read(&page_cache_size);
- shmem = atomic_read(&shmem_nrpages);
- if (cached > shmem)
- cached -= shmem;
/* Sometimes we want to use more memory than we have. */
if (sysctl_overcommit_memory)
return 1;
free = atomic_read(&buffermem_pages);
- free += cached;
+ free += atomic_read(&page_cache_size) ;
+ free -= atomic_read(&shmem_nrpages);
free += nr_free_pages();
free += nr_swap_pages;
diff -uNr 4-ac9/mm/shmem.c c/mm/shmem.c
--- 4-ac9/mm/shmem.c Thu May 17 13:17:37 2001
+++ c/mm/shmem.c Thu May 17 10:54:03 2001
@@ -35,6 +35,8 @@
#define ENTRIES_PER_PAGE (PAGE_SIZE/sizeof(unsigned long))
+#define SHMEM_SB(sb) (&sb->u.shmem_sb)
+
static struct super_operations shmem_ops;
static struct address_space_operations shmem_aops;
static struct file_operations shmem_file_operations;
@@ -50,44 +52,6 @@
#define BLOCKS_PER_PAGE (PAGE_SIZE/512)
/*
- * shmem_recalc_inode - recalculate the size of an inode
- *
- * @inode: inode to recalc
- * @swap: additional swap pages freed externally
- *
- * We have to calculate the free blocks since the mm can drop pages
- * behind our back
- *
- * But we know that normally
- * inodes->i_blocks/BLOCKS_PER_PAGE ==
- * inode->i_mapping->nrpages + info->swapped
- *
- * So the mm freed
- * inodes->i_blocks/BLOCKS_PER_PAGE -
- * (inode->i_mapping->nrpages + info->swapped)
- *
- * It has to be called with the spinlock held.
- *
- * The swap parameter is a performance hack for truncate.
- */
-
-static void shmem_recalc_inode(struct inode * inode, unsigned long swap)
-{
- unsigned long freed;
-
- freed = (inode->i_blocks/BLOCKS_PER_PAGE) -
- (inode->i_mapping->nrpages + SHMEM_I(inode)->swapped);
- if (freed){
- struct shmem_sb_info * info = &inode->i_sb->u.shmem_sb;
- inode->i_blocks -= freed*BLOCKS_PER_PAGE;
- spin_lock (&info->stat_lock);
- info->free_blocks += freed;
- spin_unlock (&info->stat_lock);
- atomic_sub(freed-swap, &shmem_nrpages);
- }
-}
-
-/*
* shmem_swp_entry - find the swap vector position in the info structure
*
* @info: info structure for the inode
@@ -318,6 +282,7 @@
unsigned long index;
unsigned long freed = 0;
struct shmem_inode_info * info = SHMEM_I(inode);
+ struct shmem_sb_info * sbinfo = SHMEM_SB(inode->i_sb);
down(&info->sem);
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
@@ -328,14 +293,28 @@
freed += shmem_truncate_indirect(info, index);
info->swapped -= freed;
- shmem_recalc_inode(inode, freed);
+ spin_lock(&sbinfo->stat_lock);
+ sbinfo->free_blocks += freed;
+ spin_unlock(&sbinfo->stat_lock);
spin_unlock (&info->lock);
up(&info->sem);
}
+static void shmem_truncatepage(struct page *page)
+{
+ struct inode *inode = (struct inode *)page->mapping->host;
+ struct shmem_sb_info * sbinfo = SHMEM_SB(inode->i_sb);
+
+ inode->i_blocks -= BLOCKS_PER_PAGE;
+ spin_lock (&sbinfo->stat_lock);
+ sbinfo->free_blocks++;
+ spin_unlock (&sbinfo->stat_lock);
+ atomic_dec(&shmem_nrpages);
+}
+
static void shmem_delete_inode(struct inode * inode)
{
- struct shmem_sb_info *info = &inode->i_sb->u.shmem_sb;
+ struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
inode->i_size = 0;
if (inode->i_op->truncate == shmem_truncate){
@@ -344,9 +323,9 @@
spin_unlock (&shmem_ilock);
shmem_truncate(inode);
}
- spin_lock (&info->stat_lock);
- info->free_inodes++;
- spin_unlock (&info->stat_lock);
+ spin_lock (&sbinfo->stat_lock);
+ sbinfo->free_inodes++;
+ spin_unlock (&sbinfo->stat_lock);
clear_inode(inode);
}
@@ -383,7 +362,6 @@
entry = shmem_swp_entry(info, page->index, 0);
if (IS_ERR(entry)) /* this had been allocted on page allocation */
BUG();
- shmem_recalc_inode(page->mapping->host, 0);
error = -EAGAIN;
if (entry->val)
BUG();
@@ -421,6 +399,7 @@
static struct page * shmem_getpage_locked(struct shmem_inode_info *info, struct inode * inode, unsigned long idx)
{
struct address_space * mapping = inode->i_mapping;
+ struct shmem_sb_info * sbinfo;
struct page * page;
swp_entry_t *entry;
@@ -487,12 +466,13 @@
info->swapped--;
spin_unlock (&info->lock);
} else {
+ sbinfo = SHMEM_SB(inode->i_sb);
spin_unlock (&info->lock);
- spin_lock (&inode->i_sb->u.shmem_sb.stat_lock);
- if (inode->i_sb->u.shmem_sb.free_blocks == 0)
+ spin_lock (&sbinfo->stat_lock);
+ if (sbinfo->free_blocks == 0)
goto no_space;
- inode->i_sb->u.shmem_sb.free_blocks--;
- spin_unlock (&inode->i_sb->u.shmem_sb.stat_lock);
+ sbinfo->free_blocks--;
+ spin_unlock (&sbinfo->stat_lock);
/* Ok, get a new page. We don't have to worry about the
* info->lock spinlock here: we cannot race against
@@ -516,7 +496,7 @@
page_cache_get(page);
return page;
no_space:
- spin_unlock (&inode->i_sb->u.shmem_sb.stat_lock);
+ spin_unlock (&sbinfo->stat_lock);
return ERR_PTR(-ENOSPC);
wait_retry:
@@ -638,14 +618,15 @@
{
struct inode * inode;
struct shmem_inode_info *info;
+ struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
- spin_lock (&sb->u.shmem_sb.stat_lock);
- if (!sb->u.shmem_sb.free_inodes) {
- spin_unlock (&sb->u.shmem_sb.stat_lock);
+ spin_lock (&sbinfo->stat_lock);
+ if (!sbinfo->free_inodes) {
+ spin_unlock (&sbinfo->stat_lock);
return NULL;
}
- sb->u.shmem_sb.free_inodes--;
- spin_unlock (&sb->u.shmem_sb.stat_lock);
+ sbinfo->free_inodes--;
+ spin_unlock (&sbinfo->stat_lock);
inode = new_inode(sb);
if (inode) {
@@ -903,24 +884,26 @@
static int shmem_statfs(struct super_block *sb, struct statfs *buf)
{
+ struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
+
buf->f_type = TMPFS_MAGIC;
buf->f_bsize = PAGE_CACHE_SIZE;
- spin_lock (&sb->u.shmem_sb.stat_lock);
- if (sb->u.shmem_sb.max_blocks == ULONG_MAX) {
+ 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 - sb->u.shmem_sb.free_blocks;
+ buf->f_blocks = buf->f_bfree + ULONG_MAX - sbinfo->free_blocks;
} else {
- buf->f_blocks = sb->u.shmem_sb.max_blocks;
- buf->f_bavail = buf->f_bfree = sb->u.shmem_sb.free_blocks;
+ buf->f_blocks = sbinfo->max_blocks;
+ buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
}
- buf->f_files = sb->u.shmem_sb.max_inodes;
- buf->f_ffree = sb->u.shmem_sb.free_inodes;
- spin_unlock (&sb->u.shmem_sb.stat_lock);
+ buf->f_files = sbinfo->max_inodes;
+ buf->f_ffree = sbinfo->free_inodes;
+ spin_unlock (&sbinfo->stat_lock);
buf->f_namelen = 255;
return 0;
}
@@ -1202,26 +1185,26 @@
int error;
unsigned long max_blocks, blocks;
unsigned long max_inodes, inodes;
- struct shmem_sb_info *info = &sb->u.shmem_sb;
+ struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
if (shmem_parse_options (data, NULL, &max_blocks, &max_inodes))
return -EINVAL;
- spin_lock(&info->stat_lock);
- blocks = info->max_blocks - info->free_blocks;
- inodes = info->max_inodes - info->free_inodes;
+ spin_lock(&sbinfo->stat_lock);
+ blocks = sbinfo->max_blocks - sbinfo->free_blocks;
+ inodes = sbinfo->max_inodes - sbinfo->free_inodes;
error = -EINVAL;
if (max_blocks < blocks)
goto out;
if (max_inodes < inodes)
goto out;
error = 0;
- info->max_blocks = max_blocks;
- info->free_blocks = max_blocks - blocks;
- info->max_inodes = max_inodes;
- info->free_inodes = max_inodes - inodes;
+ sbinfo->max_blocks = max_blocks;
+ sbinfo->free_blocks = max_blocks - blocks;
+ sbinfo->max_inodes = max_inodes;
+ sbinfo->free_inodes = max_inodes - inodes;
out:
- spin_unlock(&info->stat_lock);
+ spin_unlock(&sbinfo->stat_lock);
return error;
}
@@ -1238,6 +1221,7 @@
unsigned long blocks = ULONG_MAX; /* unlimited */
unsigned long inodes = ULONG_MAX; /* unlimited */
int mode = S_IRWXUGO | S_ISVTX;
+ struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
#ifdef CONFIG_TMPFS
if (shmem_parse_options (data, &mode, &blocks, &inodes)) {
@@ -1246,11 +1230,11 @@
}
#endif
- spin_lock_init (&sb->u.shmem_sb.stat_lock);
- sb->u.shmem_sb.max_blocks = blocks;
- sb->u.shmem_sb.free_blocks = blocks;
- sb->u.shmem_sb.max_inodes = inodes;
- sb->u.shmem_sb.free_inodes = inodes;
+ spin_lock_init (&sbinfo->stat_lock);
+ sbinfo->max_blocks = blocks;
+ sbinfo->free_blocks = blocks;
+ sbinfo->max_inodes = inodes;
+ sbinfo->free_inodes = inodes;
sb->s_maxbytes = (unsigned long long) SHMEM_MAX_BLOCKS << PAGE_CACHE_SHIFT;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
@@ -1272,7 +1256,8 @@
static struct address_space_operations shmem_aops = {
- writepage: shmem_writepage
+ truncatepage: shmem_truncatepage,
+ writepage: shmem_writepage,
};
static struct file_operations shmem_file_operations = {
reply other threads:[~2001-05-17 15:08 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=m3itj0t3wx.fsf@linux.local \
--to=cr@sap.com \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.