2/6: ckrm_numtasks_tasksupport

Adds task management support by defining a function to be called from
fork() to see if the class is within its share allocation
Sets interface to be called from core when a class is moved to a class.
--

Signed-Off-By: Chandra Seetharaman <[EMAIL PROTECTED]>

 include/linux/ckrm_tsk.h    |   28 +++++++++++
 kernel/ckrm/ckrm_numtasks.c |  104 +++++++++++++++++++++++++++++++++++++++++++-
 kernel/fork.c               |    7 ++
 3 files changed, 137 insertions(+), 2 deletions(-)

Index: linux2617-rc2/include/linux/ckrm_tsk.h
===================================================================
--- /dev/null
+++ linux2617-rc2/include/linux/ckrm_tsk.h
@@ -0,0 +1,28 @@
+/* ckrm_tsk.h - No. of tasks resource controller for CKRM
+ *
+ * Copyright (C) Chandra Seetharaman, IBM Corp. 2003, 2004, 2005
+ *
+ * Provides No. of tasks resource controller for CKRM
+ *
+ * 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_CKRM_TSK_H
+#define _LINUX_CKRM_TSK_H
+
+#ifdef CONFIG_CKRM_RES_NUMTASKS
+#include <linux/ckrm_rc.h>
+
+extern int numtasks_allow_fork(struct ckrm_class *);
+
+#else /* CONFIG_CKRM_RES_NUMTASKS */
+
+#define numtasks_allow_fork(class) (0)
+
+#endif /* CONFIG_CKRM_RES_NUMTASKS */
+#endif /* _LINUX_CKRM_RES_H */
Index: linux2617-rc2/kernel/ckrm/ckrm_numtasks.c
===================================================================
--- linux2617-rc2.orig/kernel/ckrm/ckrm_numtasks.c
+++ linux2617-rc2/kernel/ckrm/ckrm_numtasks.c
@@ -21,7 +21,19 @@
 static const char res_ctlr_name[] = "numtasks";
 
 struct ckrm_numtasks {
+       struct ckrm_class *class;       /* the class i am part of... */
        struct ckrm_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 class's class_lock */
+       atomic_t cnt_cur_alloc; /* current alloc from self */
+       atomic_t cnt_borrowed;  /* borrowed from the parent */
+
+       /* stats */
+       int successes;
+       int failures;
 };
 
 struct ckrm_controller numtasks_ctlr;
@@ -33,6 +45,84 @@ static struct ckrm_numtasks *get_shares_
        return NULL;
 }
 
+static struct ckrm_numtasks *get_class_numtasks(struct ckrm_class *class)
+{
+       return get_shares_numtasks(ckrm_get_controller_shares(class,
+                                               &numtasks_ctlr));
+}
+
+int numtasks_allow_fork(struct ckrm_class *class)
+{
+       struct ckrm_numtasks *res;
+
+       /* controller is not registered; no class is given */
+       if ((numtasks_ctlr.ctlr_id == CKRM_NO_RES_ID) || (class == NULL))
+               return 0;
+       res = get_class_numtasks(class);
+
+       /* numtasks not available for this class */
+       if (!res)
+               return 0;
+
+       if (res->cnt_max_shares == CKRM_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 ckrm_numtasks *res)
+{
+       atomic_inc(&res->cnt_cur_alloc);
+
+       if (ckrm_is_class_root(res->class)) {
+               res->successes++;
+               return;
+       }
+       /* Do we need to borrow from our parent ? */
+       if ((res->cnt_unused == CKRM_SHARE_DONT_CARE) ||
+                       (atomic_read(&res->cnt_cur_alloc) > res->cnt_unused)) {
+               inc_usage_count(get_class_numtasks(res->class->parent));
+               atomic_inc(&res->cnt_borrowed);
+       } else
+               res->successes++;
+}
+
+static void dec_usage_count(struct ckrm_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_class_numtasks(res->class->parent));
+       }
+}
+
+static void numtasks_move_task(struct task_struct *task,
+               struct ckrm_shares *old, struct ckrm_shares *new)
+{
+       struct ckrm_numtasks *oldres, *newres;
+
+       if (old == new)
+               return;
+
+       /* Decrement usage count of old class */
+       oldres = get_shares_numtasks(old);
+       if (oldres)
+               dec_usage_count(oldres);
+
+       /* Increment usage count of new class */
+       newres = get_shares_numtasks(new);
+       if (newres)
+               inc_usage_count(newres);
+}
+
 /* Initialize share struct values */
 static void numtasks_res_init_one(struct ckrm_numtasks *numtasks_res)
 {
@@ -50,6 +140,7 @@ static struct ckrm_shares *numtasks_allo
        res = kzalloc(sizeof(struct ckrm_numtasks), GFP_KERNEL);
        if (!res)
                return NULL;
+       res->class = class;
        numtasks_res_init_one(res);
        return &res->shares;
 }
@@ -60,7 +151,17 @@ static struct ckrm_shares *numtasks_allo
  */
 static void numtasks_free_shares_struct(struct ckrm_shares *my_res)
 {
-       kfree(get_shares_numtasks(my_res));
+       struct ckrm_numtasks *res, *parres;
+       int i, borrowed;
+
+       res = get_shares_numtasks(my_res);
+       if (!ckrm_is_class_root(res->class)) {
+               parres = get_class_numtasks(res->class->parent);
+               borrowed = atomic_read(&res->cnt_borrowed);
+               for (i = 0; i < borrowed; i++)
+                       dec_usage_count(parres);
+       }
+       kfree(res);
 }
 
 struct ckrm_controller numtasks_ctlr = {
@@ -69,6 +170,7 @@ struct ckrm_controller numtasks_ctlr = {
        .ctlr_id = CKRM_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_ckrm_numtasks_res(void)
Index: linux2617-rc2/kernel/fork.c
===================================================================
--- linux2617-rc2.orig/kernel/fork.c
+++ linux2617-rc2/kernel/fork.c
@@ -45,6 +45,7 @@
 #include <linux/acct.h>
 #include <linux/cn_proc.h>
 #include <linux/ckrm.h>
+#include <linux/ckrm_tsk.h>
 
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
@@ -1310,7 +1311,7 @@ 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;
 
@@ -1323,6 +1324,10 @@ long do_fork(unsigned long clone_flags,
                        clone_flags |= CLONE_PTRACE;
        }
 
+       rc = numtasks_allow_fork(current->class);
+       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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