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Message-ID: <20070507194948.GG19966@holomorphy.com>
Date: Mon, 7 May 2007 12:49:48 -0700
From: William Lee Irwin III <wli@...omorphy.com>
To: Andrea Righi <righiandr@...rs.sourceforge.net>
Cc: LKML <linux-kernel@...r.kernel.org>, linux-mm@...ck.org
Subject: Re: [RFC][PATCH] VM: per-user overcommit policy
On Mon, May 07, 2007 at 12:16:58PM -0700, William Lee Irwin III wrote:
> The following stanza occurs often:
> + if (!vm_acct_get_config(&v, current->uid)) {
> + overcommit_memory = v.overcommit_memory;
> + overcommit_ratio = v.overcommit_ratio;
> + } else {
> + overcommit_memory = sysctl_overcommit_memory;
> + overcommit_ratio = sysctl_overcommit_ratio;
> + }
>
> suggesting that vm_acct_get_config() isn't the proper abstraction.
> Instead of
> int vm_acct_get_config(struct vm_acct_values *, uid_t);
> you could just have
> int vm_acct_get_config(struct vm_acct_values *);
> which conditionally uses current->uid, and then unconditionally use
> v.overcommit_memory and v.overcommit_ratio vs. sysctl_overcommit_memory
> and sysctl_overcommit_ratio in the sequel.
Something like this (untested/uncompiled) may do.
Index: righi/include/linux/mman.h
===================================================================
--- righi.orig/include/linux/mman.h 2007-05-07 12:36:05.897386369 -0700
+++ righi/include/linux/mman.h 2007-05-07 12:42:29.803263919 -0700
@@ -18,14 +18,13 @@
extern int sysctl_overcommit_memory;
extern int sysctl_overcommit_ratio;
extern atomic_t vm_committed_space;
-#ifdef CONFIG_VM_ACCT_USER
+
struct vm_acct_values
{
int overcommit_memory;
int overcommit_ratio;
};
-extern int vm_acct_get_config(struct vm_acct_values *v, uid_t uid);
-#endif
+void vm_acct_get_config(struct vm_acct_values *v);
#ifdef CONFIG_SMP
extern void vm_acct_memory(long pages);
Index: righi/mm/swap.c
===================================================================
--- righi.orig/mm/swap.c 2007-05-07 12:37:13.965265337 -0700
+++ righi/mm/swap.c 2007-05-07 12:42:14.914415451 -0700
@@ -482,10 +482,11 @@
/*
* Get user VM configuration from the hash list.
*/
-int vm_acct_get_config(struct vm_acct_values *v, uid_t uid)
+void vm_acct_get_config(struct vm_acct_values *v)
{
struct hlist_node *elem;
vm_acct_hash_t *p;
+ uid_t uid = current->uid;
spin_lock_irq(&vm_acct_lock);
hlist_for_each_entry(p, elem, &vm_acct_hash[vm_acct_hashfn(uid)],
@@ -494,12 +495,12 @@
v->overcommit_memory = p->val.overcommit_memory;
v->overcommit_ratio = p->val.overcommit_ratio;
spin_unlock_irq(&vm_acct_lock);
- return 0;
+ return;
}
}
spin_unlock_irq(&vm_acct_lock);
-
- return -ENOENT;
+ v->overcommit_memory = sysctl_overcommit_memory;
+ v->overcommit_ratio = sysctl_overcommit_ratio;
}
/*
@@ -646,8 +647,13 @@
return 0;
}
__initcall(init_vm_acct);
-
-#endif /* CONFIG_VM_ACCT_USER */
+#else /* !CONFIG_VM_ACCT_USER */
+void vm_acct_get_config(struct vm_acct_values *v)
+{
+ v->overcommit_memory = sysctl_overcommit_memory;
+ v->overcommit_ratio = sysctl_overcommit_ratio;
+}
+#endif /* !CONFIG_VM_ACCT_USER */
#ifdef CONFIG_SMP
/*
Index: righi/ipc/shm.c
===================================================================
--- righi.orig/ipc/shm.c 2007-05-07 12:40:35.576754521 -0700
+++ righi/ipc/shm.c 2007-05-07 12:43:32.714849046 -0700
@@ -370,24 +370,15 @@
shp->mlock_user = current->user;
} else {
int acctflag = VM_ACCOUNT;
-#ifdef CONFIG_VM_ACCT_USER
- int overcommit_memory;
struct vm_acct_values v;
- if (!vm_acct_get_config(&v, current->uid)) {
- overcommit_memory = v.overcommit_memory;
- } else {
- overcommit_memory = sysctl_overcommit_memory;
- }
-#else
-#define overcommit_memory sysctl_overcommit_memory
-#endif
+ vm_acct_get_config(&v);
/*
* Do not allow no accounting for OVERCOMMIT_NEVER, even
* if it's asked for.
*/
if ((shmflg & SHM_NORESERVE) &&
- overcommit_memory != OVERCOMMIT_NEVER)
+ v.overcommit_memory != OVERCOMMIT_NEVER)
acctflag = 0;
sprintf (name, "SYSV%08x", key);
file = shmem_file_setup(name, size, acctflag);
Index: righi/mm/mmap.c
===================================================================
--- righi.orig/mm/mmap.c 2007-05-07 12:43:48.143728287 -0700
+++ righi/mm/mmap.c 2007-05-07 12:46:02.775400509 -0700
@@ -96,30 +96,18 @@
int __vm_enough_memory(long pages, int cap_sys_admin)
{
unsigned long free, allowed;
-#ifdef CONFIG_VM_ACCT_USER
- int overcommit_memory, overcommit_ratio;
struct vm_acct_values v;
- if (!vm_acct_get_config(&v, current->uid)) {
- overcommit_memory = v.overcommit_memory;
- overcommit_ratio = v.overcommit_ratio;
- } else {
- overcommit_memory = sysctl_overcommit_memory;
- overcommit_ratio = sysctl_overcommit_ratio;
- }
-#else
-#define overcommit_memory sysctl_overcommit_memory
-#define overcommit_ratio sysctl_overcommit_ratio
-#endif
+ vm_acct_get_config(&v);
vm_acct_memory(pages);
/*
* Sometimes we want to use more memory than we have
*/
- if (overcommit_memory == OVERCOMMIT_ALWAYS)
+ if (v.overcommit_memory == OVERCOMMIT_ALWAYS)
return 0;
- if (overcommit_memory == OVERCOMMIT_GUESS) {
+ if (v.overcommit_memory == OVERCOMMIT_GUESS) {
unsigned long n;
free = global_page_state(NR_FILE_PAGES);
@@ -170,7 +158,7 @@
}
allowed = (totalram_pages - hugetlb_total_pages())
- * overcommit_ratio / 100;
+ * v.overcommit_ratio / 100;
/*
* Leave the last 3% for root
*/
@@ -916,10 +904,7 @@
struct rb_node ** rb_link, * rb_parent;
int accountable = 1;
unsigned long charged = 0, reqprot = prot;
-#ifdef CONFIG_VM_ACCT_USER
- int overcommit_memory;
struct vm_acct_values v;
-#endif
/*
* Does the application expect PROT_READ to imply PROT_EXEC?
@@ -1059,15 +1044,9 @@
if (!may_expand_vm(mm, len >> PAGE_SHIFT))
return -ENOMEM;
-#ifdef CONFIG_VM_ACCT_USER
- if (!vm_acct_get_config(&v, current->uid)) {
- overcommit_memory = v.overcommit_memory;
- } else {
- overcommit_memory = sysctl_overcommit_memory;
- }
-#endif
+ vm_acct_get_config(&v);
if (accountable && (!(flags & MAP_NORESERVE) ||
- overcommit_memory == OVERCOMMIT_NEVER)) {
+ v.overcommit_memory == OVERCOMMIT_NEVER)) {
if (vm_flags & VM_SHARED) {
/* Check memory availability in shmem_file_setup? */
vm_flags |= VM_ACCOUNT;
Index: righi/mm/nommu.c
===================================================================
--- righi.orig/mm/nommu.c 2007-05-07 12:46:09.667793284 -0700
+++ righi/mm/nommu.c 2007-05-07 12:46:52.490233596 -0700
@@ -1240,31 +1240,18 @@
int __vm_enough_memory(long pages, int cap_sys_admin)
{
unsigned long free, allowed;
-#ifdef CONFIG_VM_ACCT_USER
- int overcommit_memory, overcommit_ratio;
struct vm_acct_values v;
- if (!vm_acct_get_config(&v, current->uid)) {
- overcommit_memory = v.overcommit_memory;
- overcommit_ratio = v.overcommit_ratio;
- } else {
- overcommit_memory = sysctl_overcommit_memory;
- overcommit_ratio = sysctl_overcommit_ratio;
- }
-#else
-#define overcommit_memory sysctl_overcommit_memory
-#define overcommit_ratio sysctl_overcommit_ratio
-#endif
-
+ vm_acct_get_config(&v);
vm_acct_memory(pages);
/*
* Sometimes we want to use more memory than we have
*/
- if (overcommit_memory == OVERCOMMIT_ALWAYS)
+ if (v.overcommit_memory == OVERCOMMIT_ALWAYS)
return 0;
- if (overcommit_memory == OVERCOMMIT_GUESS) {
+ if (v.overcommit_memory == OVERCOMMIT_GUESS) {
unsigned long n;
free = global_page_state(NR_FILE_PAGES);
@@ -1314,7 +1301,7 @@
goto error;
}
- allowed = totalram_pages * overcommit_ratio / 100;
+ allowed = totalram_pages * v.overcommit_ratio / 100;
/*
* Leave the last 3% for root
*/
-
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