2/6: numtasks_tasksupport
Adds task management support by defining a function to be called from
fork() to see if the resource group is within its share allocation
Sets interface to be called from core when a task is moved to a resource
group.
--
Signed-Off-By: Chandra Seetharaman <[email protected]>
include/linux/numtasks.h | 28 +++++++++++
kernel/fork.c | 7 ++
kernel/res_group/numtasks.c | 104 +++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 137 insertions(+), 2 deletions(-)
Index: linux-2617-rc3/include/linux/numtasks.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2617-rc3/include/linux/numtasks.h 2006-04-27 10:18:50.000000000 -0700
@@ -0,0 +1,28 @@
+/* numtasks.h - No. of tasks resource controller for Resource Groups
+ *
+ * Copyright (C) Chandra Seetharaman, IBM Corp. 2003, 2004, 2005
+ *
+ * Provides No. of tasks resource controller for Resource Groups
+ *
+ * Latest version, more details at http://ckrm.sf.net
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+#ifndef _LINUX_NUMTASKS_H
+#define _LINUX_NUMTASKS_H
+
+#ifdef CONFIG_RES_GROUPS_NUMTASKS
+#include <linux/res_group_rc.h>
+
+extern int numtasks_allow_fork(struct resource_group *);
+
+#else /* CONFIG_RES_GROUPS_NUMTASKS */
+
+#define numtasks_allow_fork(rgroup) (0)
+
+#endif /* CONFIG_RES_GROUPS_NUMTASKS */
+#endif /* _LINUX_NUMTASKS_H */
Index: linux-2617-rc3/kernel/res_group/numtasks.c
===================================================================
--- linux-2617-rc3.orig/kernel/res_group/numtasks.c 2006-04-27 10:18:49.000000000 -0700
+++ linux-2617-rc3/kernel/res_group/numtasks.c 2006-04-27 10:18:50.000000000 -0700
@@ -21,7 +21,19 @@
static const char res_ctlr_name[] = "numtasks";
struct numtasks {
+ struct resource_group *rgroup;/* resource group i am part of... */
struct res_shares shares;
+ int cnt_min_shares; /* num_tasks min_shares in local units */
+ int cnt_unused; /* has to borrow if more than this is needed */
+ int cnt_max_shares; /* no tasks over this limit. */
+ /* Three above cnt_* fields are protected
+ * by resource group's group_lock */
+ atomic_t cnt_cur_alloc; /* current alloc from self */
+ atomic_t cnt_borrowed; /* borrowed from the parent */
+
+ /* stats */
+ int successes;
+ int failures;
};
struct res_controller numtasks_ctlr;
@@ -33,6 +45,84 @@ static struct numtasks *get_shares_numta
return NULL;
}
+static struct numtasks *get_numtasks(struct resource_group *rgroup)
+{
+ return get_shares_numtasks(get_controller_shares(rgroup,
+ &numtasks_ctlr));
+}
+
+int numtasks_allow_fork(struct resource_group *rgroup)
+{
+ struct numtasks *res;
+
+ /* controller is not registered; no resource group is given */
+ if ((numtasks_ctlr.ctlr_id == NO_RES_ID) || (rgroup == NULL))
+ return 0;
+ res = get_numtasks(rgroup);
+
+ /* numtasks not available for this resource group */
+ if (!res)
+ return 0;
+
+ if (res->cnt_max_shares == SHARE_DONT_CARE)
+ return 0;
+
+ /* Over the limit ? */
+ if (atomic_read(&res->cnt_cur_alloc) >= res->cnt_max_shares) {
+ res->failures++;
+ return -ENOSPC;
+ }
+
+ return 0;
+}
+
+static void inc_usage_count(struct numtasks *res)
+{
+ atomic_inc(&res->cnt_cur_alloc);
+
+ if (is_res_group_root(res->rgroup)) {
+ res->successes++;
+ return;
+ }
+ /* Do we need to borrow from our parent ? */
+ if ((res->cnt_unused == SHARE_DONT_CARE) ||
+ (atomic_read(&res->cnt_cur_alloc) > res->cnt_unused)) {
+ inc_usage_count(get_numtasks(res->rgroup->parent));
+ atomic_inc(&res->cnt_borrowed);
+ } else
+ res->successes++;
+}
+
+static void dec_usage_count(struct numtasks *res)
+{
+ if (atomic_read(&res->cnt_cur_alloc) == 0)
+ return;
+ atomic_dec(&res->cnt_cur_alloc);
+ if (atomic_read(&res->cnt_borrowed) > 0) {
+ atomic_dec(&res->cnt_borrowed);
+ dec_usage_count(get_numtasks(res->rgroup->parent));
+ }
+}
+
+static void numtasks_move_task(struct task_struct *task,
+ struct res_shares *old, struct res_shares *new)
+{
+ struct numtasks *oldres, *newres;
+
+ if (old == new)
+ return;
+
+ /* Decrement usage count of old resource group */
+ oldres = get_shares_numtasks(old);
+ if (oldres)
+ dec_usage_count(oldres);
+
+ /* Increment usage count of new resource group */
+ newres = get_shares_numtasks(new);
+ if (newres)
+ inc_usage_count(newres);
+}
+
/* Initialize share struct values */
static void numtasks_res_init_one(struct numtasks *numtasks_res)
{
@@ -50,6 +140,7 @@ static struct res_shares *numtasks_alloc
res = kzalloc(sizeof(struct numtasks), GFP_KERNEL);
if (!res)
return NULL;
+ res->rgroup = rgroup;
numtasks_res_init_one(res);
return &res->shares;
}
@@ -60,7 +151,17 @@ static struct res_shares *numtasks_alloc
*/
static void numtasks_free_shares_struct(struct res_shares *my_res)
{
- kfree(get_shares_numtasks(my_res));
+ struct numtasks *res, *parres;
+ int i, borrowed;
+
+ res = get_shares_numtasks(my_res);
+ if (!is_res_group_root(res->rgroup)) {
+ parres = get_numtasks(res->rgroup->parent);
+ borrowed = atomic_read(&res->cnt_borrowed);
+ for (i = 0; i < borrowed; i++)
+ dec_usage_count(parres);
+ }
+ kfree(res);
}
struct res_controller numtasks_ctlr = {
@@ -69,6 +170,7 @@ struct res_controller numtasks_ctlr = {
.ctlr_id = NO_RES_ID,
.alloc_shares_struct = numtasks_alloc_shares_struct,
.free_shares_struct = numtasks_free_shares_struct,
+ .move_task = numtasks_move_task,
};
int __init init_numtasks_res(void)
Index: linux-2617-rc3/kernel/fork.c
===================================================================
--- linux-2617-rc3.orig/kernel/fork.c 2006-04-27 10:14:38.000000000 -0700
+++ linux-2617-rc3/kernel/fork.c 2006-04-27 10:18:50.000000000 -0700
@@ -45,6 +45,7 @@
#include <linux/acct.h>
#include <linux/cn_proc.h>
#include <linux/res_group.h>
+#include <linux/numtasks.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -1311,7 +1312,7 @@ long do_fork(unsigned long clone_flags,
int __user *child_tidptr)
{
struct task_struct *p;
- int trace = 0;
+ int trace = 0, rc;
struct pid *pid = alloc_pid();
long nr;
@@ -1324,6 +1325,10 @@ long do_fork(unsigned long clone_flags,
clone_flags |= CLONE_PTRACE;
}
+ rc = numtasks_allow_fork(current->res_group);
+ if (rc)
+ return rc;
+
p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, nr);
/*
* Do this prior waking up the new thread - the thread pointer
--
----------------------------------------------------------------------
Chandra Seetharaman | Be careful what you choose....
- [email protected] | .......you may get it.
----------------------------------------------------------------------
-
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