[PATCH 4/6] CKRM numtasks resource controller

[Shailabh Nagar <nagar@watson.ibm.com>]

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diff -Nru a/include/linux/ckrm_tsk.h b/include/linux/ckrm_tsk.h
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/include/linux/ckrm_tsk.h	Wed Apr 28 22:41:05 2004
@@ -0,0 +1,41 @@
+/* ckrm_tsk.h - No. of tasks resource controller for CKRM
+ *
+ * Copyright (C) Chandra Seetharaman, IBM Corp. 2003
+ * 
+ * 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.
+ *
+ */
+
+/* Changes
+ *
+ * 31 Mar 2004
+ *    Created.
+ */
+
+#ifndef _LINUX_CKRM_TSK_H
+#define _LINUX_CKRM_TSK_H
+
+#include <linux/ckrm_rc.h>
+
+#ifdef CONFIG_CKRM_RES_NUMTASKS
+
+extern int numtasks_get_ref(void *, int);
+extern int numtasks_get_ref_resid(void *, int, int);
+extern void numtasks_put_ref(void *);
+
+#else
+
+#define numtasks_get_ref(a, b)		1
+#define numtasks_get_ref_resid(a, b, c)		1
+#define numtasks_put_ref(a)
+
+#endif
+
+#endif // _LINUX_CKRM_RES_H
diff -Nru a/kernel/ckrm/ckrm_tasks.c b/kernel/ckrm/ckrm_tasks.c
--- /dev/null	Wed Dec 31 16:00:00 1969
+++ b/kernel/ckrm/ckrm_tasks.c	Wed Apr 28 22:41:05 2004
@@ -0,0 +1,509 @@
+/* ckrm_numtasks.c - "Number of tasks" resource controller for CKRM
+ *
+ * Copyright (C) Chandra Seetharaman,  IBM Corp. 2003
+ * 
+ * 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.
+ *
+ */
+
+/* Changes
+ * 
+ * 31 Mar 2004: Created
+ * 
+ */
+
+/*
+ * Code Description: TBD
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <asm/errno.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/ckrm.h>
+#include <linux/ckrm_rc.h>
+#include <linux/ckrm_tc.h>
+
+#define TOTAL_NUM_TASKS (131072) // 128 K
+#define NUMTASKS_DEBUG
+#define NUMTASKS_NAME "numtasks"
+
+typedef struct ckrm_numtasks {
+	struct ckrm_core_class *core; // the core i am part of...
+	struct ckrm_core_class *parent; // parent of the core above.
+	struct ckrm_shares shares;
+	spinlock_t cnt_lock; // always grab parent's lock first and then child's
+	int cnt_guarantee; // num_tasks guarantee in local units
+	int cnt_unused; // has to borrow if more than this is needed
+	int cnt_limit; // no tasks over this limit.
+	atomic_t cnt_cur_alloc; // current alloc from self
+	atomic_t cnt_borrowed; // borrowed from the parent
+
+	int over_guarantee; //turn on/off when cur_alloc goes over/under guarantee
+
+	// internally maintained statictics to compare with max numbers
+	int limit_failures; // no. of failures 'cause the request was over the limit
+	int borrow_sucesses; // no. of successful borrows
+	int borrow_failures; // no. of borrow faileures
+
+	// Maximum the specific statictics has reached.
+	int max_limit_failures;
+	int max_borrow_sucesses;
+	int max_borrow_failures;
+
+	// Total number of specific statistics
+	int tot_limit_failures;
+	int tot_borrow_sucesses;
+	int tot_borrow_failures;
+} ckrm_numtasks_t;
+
+struct ckrm_res_ctlr numtasks_rcbs;
+
+/* Initialize rescls values
+ * May be called on each rcfs unmount or as part of error recovery
+ * to make share values sane.
+ * Does not traverse hierarchy reinitializing children.
+ */
+static void
+numtasks_res_initcls_one(ckrm_numtasks_t *res)
+{
+	res->shares.my_guarantee     = CKRM_SHARE_DONTCARE;
+	res->shares.my_limit         = CKRM_SHARE_DONTCARE;
+	res->shares.total_guarantee  = CKRM_SHARE_DFLT_TOTAL_GUARANTEE;
+	res->shares.max_limit        = CKRM_SHARE_DFLT_MAX_LIMIT;
+	res->shares.unused_guarantee = CKRM_SHARE_DFLT_TOTAL_GUARANTEE;
+	res->shares.cur_max_limit    = 0;
+
+	res->cnt_guarantee           = CKRM_SHARE_DONTCARE;
+	res->cnt_unused              = CKRM_SHARE_DONTCARE;
+	res->cnt_limit               = CKRM_SHARE_DONTCARE;
+
+	res->over_guarantee          = 0;
+
+	res->limit_failures          = 0;
+	res->borrow_sucesses         = 0;
+	res->borrow_failures         = 0;
+
+	res->max_limit_failures      = 0;
+	res->max_borrow_sucesses     = 0;
+	res->max_borrow_failures     = 0;
+
+	res->tot_limit_failures      = 0;
+	res->tot_borrow_sucesses     = 0;
+	res->tot_borrow_failures     = 0;
+
+	atomic_set(&res->cnt_cur_alloc, 0);
+	atomic_set(&res->cnt_borrowed, 0);
+	return;
+}
+
+#if 0	
+static void
+numtasks_res_initcls(void *my_res)
+{
+	ckrm_numtasks_t *res = my_res;
+
+	/* Write a version which propagates values all the way down 
+	   and replace rcbs callback with that version */
+	
+}
+#endif
+
+int
+numtasks_get_ref(void *arg, int force)
+{
+	int rc, resid = numtasks_rcbs.resid;
+	ckrm_numtasks_t *res;
+	ckrm_core_class_t *core = arg;
+
+	if ((resid < 0) || (core == NULL))
+		return 1;
+
+	res = ckrm_get_res_class(core, resid, ckrm_numtasks_t);
+	if (res == NULL) 
+		return 1;
+
+	atomic_inc(&res->cnt_cur_alloc);
+
+	rc = 1;
+	if (((res->parent) && (res->cnt_unused == CKRM_SHARE_DONTCARE)) ||
+			(atomic_read(&res->cnt_cur_alloc) > res->cnt_unused)) {
+
+		rc = 0;
+		if (!force && (res->cnt_limit != CKRM_SHARE_DONTCARE) && 
+				(atomic_read(&res->cnt_cur_alloc) > res->cnt_limit)) {
+			res->limit_failures++;
+			res->tot_limit_failures++;
+		} else if (res->parent != NULL) {
+			if ((rc = numtasks_get_ref(res->parent, force)) == 1) {
+				atomic_inc(&res->cnt_borrowed);
+				res->borrow_sucesses++;
+				res->tot_borrow_sucesses++;
+				res->over_guarantee = 1;
+			} else {
+				res->borrow_failures++;
+				res->tot_borrow_failures++;
+			}
+		} else {
+			rc = force;
+		}
+	} else if (res->over_guarantee) {
+		res->over_guarantee = 0;
+
+		if (res->max_limit_failures < res->limit_failures) {
+			res->max_limit_failures = res->limit_failures;
+		}
+		if (res->max_borrow_sucesses < res->borrow_sucesses) {
+			res->max_borrow_sucesses = res->borrow_sucesses;
+		}
+		if (res->max_borrow_failures < res->borrow_failures) {
+			res->max_borrow_failures = res->borrow_failures;
+		}
+		res->limit_failures = 0;
+		res->borrow_sucesses = 0;
+		res->borrow_failures = 0;
+	}
+
+	if (!rc) {
+		atomic_dec(&res->cnt_cur_alloc);
+	}
+	return rc;
+}
+
+void
+numtasks_put_ref(void *arg)
+{
+	int resid = numtasks_rcbs.resid;
+	ckrm_numtasks_t *res;
+	ckrm_core_class_t *core = arg;
+
+	if ((resid == -1) || (core == NULL)) {
+		return;
+	}
+
+	res = ckrm_get_res_class(core, resid, ckrm_numtasks_t);
+	if (res == NULL) 
+		return;
+	atomic_dec(&res->cnt_cur_alloc);
+	if (atomic_read(&res->cnt_borrowed) > 0) {
+		atomic_dec(&res->cnt_borrowed);
+		numtasks_put_ref(res->parent);
+	}
+	return;
+}
+
+static void *
+numtasks_res_alloc(struct ckrm_core_class *core, struct ckrm_core_class *parent)
+{
+	ckrm_numtasks_t *res;
+	
+	res = kmalloc(sizeof(ckrm_numtasks_t), GFP_ATOMIC);
+	
+	if (res) {
+		res->core = core;
+		res->parent = parent;
+		numtasks_res_initcls_one(res);
+		res->cnt_lock = SPIN_LOCK_UNLOCKED;
+		if (parent == NULL) {
+			// I am part of root class. so set the max tasks to available
+			// default
+			res->cnt_guarantee = TOTAL_NUM_TASKS;
+			res->cnt_unused =  TOTAL_NUM_TASKS;
+			res->cnt_limit = TOTAL_NUM_TASKS;
+		}
+	} else {
+		printk(KERN_ERR "numtasks_res_alloc: failed GFP_ATOMIC alloc\n");
+	}
+	return res;
+}
+
+/*
+ * No locking of this resource class object necessary as we are not
+ * supposed to be assigned (or used) when/after this function is called.
+ */
+static void
+numtasks_res_free(void *my_res)
+{
+	ckrm_numtasks_t *res = my_res, *parres, *childres;
+	ckrm_core_class_t *child = NULL;
+	int i, borrowed, maxlimit, resid = numtasks_rcbs.resid;
+
+	if (!res) 
+		return;
+
+	// Assuming there will be no children when this function is called
+	
+	parres = ckrm_get_res_class(res->parent, resid, ckrm_numtasks_t);
+
+	if (unlikely(atomic_read(&res->cnt_cur_alloc) != 0 ||
+				atomic_read(&res->cnt_borrowed))) {
+		printk(KERN_ERR "numtasks_res_free: resource still alloc'd %p\n", res);
+		if ((borrowed = atomic_read(&res->cnt_borrowed)) > 0) {
+			for (i = 0; i < borrowed; i++) {
+				numtasks_put_ref(parres->core);
+			}
+		}
+	}
+
+	// return child's limit/guarantee to parent node
+	spin_lock(&parres->cnt_lock);
+	child_guarantee_changed(&parres->shares, res->shares.my_guarantee, 0);
+
+	// run thru parent's children and get the new max_limit of the parent
+	ckrm_lock_hier(parres->core);
+	maxlimit = 0;
+	while ((child = ckrm_get_next_child(parres->core, child)) != NULL) {
+		childres = ckrm_get_res_class(child, resid, ckrm_numtasks_t);
+		if (maxlimit < childres->shares.my_limit) {
+			maxlimit = childres->shares.my_limit;
+		}
+	}
+	ckrm_unlock_hier(parres->core);
+	if (parres->shares.cur_max_limit < maxlimit) {
+		parres->shares.cur_max_limit = maxlimit;
+	}
+
+	spin_unlock(&parres->cnt_lock);
+	kfree(res);
+	return;
+}
+/*
+ * Recalculate the guarantee and limit in real units... and propagate the
+ * same to children.
+ * Caller is responsible for protecting res and for the integrity of parres
+ */
+static void
+recalc_and_propagate(ckrm_numtasks_t *res, ckrm_numtasks_t *parres)
+{
+	ckrm_core_class_t *child = NULL;
+	ckrm_numtasks_t *childres;
+	int resid = numtasks_rcbs.resid;
+
+	if (parres) {
+		struct ckrm_shares *par = &parres->shares;
+		struct ckrm_shares *self = &res->shares;
+
+		// calculate cnt_guarantee and cnt_limit
+		//
+		if (parres->cnt_guarantee == CKRM_SHARE_DONTCARE) {
+			res->cnt_guarantee = CKRM_SHARE_DONTCARE;
+		} else {
+			res->cnt_guarantee = (self->my_guarantee * parres->cnt_guarantee) 
+					/ par->total_guarantee;
+		}
+		if (parres->cnt_limit == CKRM_SHARE_DONTCARE) {
+			res->cnt_limit = CKRM_SHARE_DONTCARE;
+		} else {
+			res->cnt_limit = (self->my_limit * parres->cnt_limit)
+					/ par->max_limit;
+		}
+
+		// Calculate unused units
+		if (res->cnt_guarantee == CKRM_SHARE_DONTCARE) {
+			res->cnt_unused = CKRM_SHARE_DONTCARE;
+		} else {
+			res->cnt_unused = (self->unused_guarantee *
+					res->cnt_guarantee) / self->total_guarantee;
+		}
+	}
+
+	// propagate to children
+	ckrm_lock_hier(res->core);
+	while ((child = ckrm_get_next_child(res->core, child)) != NULL) {
+		childres = ckrm_get_res_class(child, resid, ckrm_numtasks_t);
+
+		spin_lock(&childres->cnt_lock);
+		recalc_and_propagate(childres, res);
+		spin_unlock(&childres->cnt_lock);
+	}
+	ckrm_unlock_hier(res->core);
+	return;
+}
+
+static int
+numtasks_set_share_values(void *my_res, struct ckrm_shares *new)
+{
+	ckrm_numtasks_t *parres, *res = my_res;
+	struct ckrm_shares *cur = &res->shares, *par;
+	int rc = -EINVAL, resid = numtasks_rcbs.resid;
+
+	if (!res) 
+		return rc;
+
+	if (res->parent) {
+		parres = ckrm_get_res_class(res->parent, resid, ckrm_numtasks_t);
+		spin_lock(&parres->cnt_lock);
+		spin_lock(&res->cnt_lock);
+		par = &parres->shares;
+	} else {
+		spin_lock(&res->cnt_lock);
+		par = NULL;
+		parres = NULL;
+	}
+
+	rc = set_shares(new, cur, par);
+
+	if ((rc == 0) && parres) {
+		// Calculate parent's unused units
+		if (parres->cnt_guarantee == CKRM_SHARE_DONTCARE) {
+			parres->cnt_unused = CKRM_SHARE_DONTCARE;
+		} else {
+			parres->cnt_unused = (par->unused_guarantee *
+					parres->cnt_guarantee) / par->total_guarantee;
+		}
+
+		recalc_and_propagate(res, parres);
+	}
+	spin_unlock(&res->cnt_lock);
+	if (res->parent) {
+		spin_unlock(&parres->cnt_lock);
+	}
+	return rc;
+}
+
+
+static int
+numtasks_get_share_values(void *my_res, struct ckrm_shares *shares)
+{
+	ckrm_numtasks_t *res = my_res;
+
+	if (!res) 
+		return -EINVAL;
+	*shares = res->shares;
+	return 0;
+}
+
+static int  
+numtasks_get_stats(void *my_res, struct seq_file *sfile)
+{
+	ckrm_numtasks_t *res = my_res;
+
+	if (!res) 
+		return -EINVAL;
+
+	seq_printf(sfile, "Number of tasks resource:\n");
+	seq_printf(sfile, "Total Over limit failures: %d\n",
+			res->tot_limit_failures);
+	seq_printf(sfile, "Total Over guarantee sucesses: %d\n",
+			res->tot_borrow_sucesses);
+	seq_printf(sfile, "Total Over guarantee failures: %d\n",
+			res->tot_borrow_failures);
+
+	seq_printf(sfile, "Maximum Over limit failures: %d\n",
+			res->max_limit_failures);
+	seq_printf(sfile, "Maximum Over guarantee sucesses: %d\n",
+			res->max_borrow_sucesses);
+	seq_printf(sfile, "Maximum Over guarantee failures: %d\n",
+			res->max_borrow_failures);
+#ifdef NUMTASKS_DEBUG
+	seq_printf(sfile, "cur_alloc %d; borrowed %d; cnt_guar %d; cnt_limit %d "
+			"unused_guarantee %d, cur_max_limit %d\n",
+			atomic_read(&res->cnt_cur_alloc),
+			atomic_read(&res->cnt_borrowed),
+			res->cnt_guarantee,
+			res->cnt_limit,
+			res->shares.unused_guarantee,
+			res->shares.cur_max_limit);
+#endif
+
+	return 0;
+}
+
+static int  
+numtasks_show_config(void *my_res, struct seq_file *sfile)
+{
+	ckrm_numtasks_t *res = my_res;
+
+	if (!res) 
+		return -EINVAL;
+
+	seq_printf(sfile, "res=%s,parameter=somevalue\n",NUMTASKS_NAME);
+	return 0;
+}
+
+static int  
+numtasks_set_config(void *my_res, const char *cfgstr)
+{
+	ckrm_numtasks_t *res = my_res;
+
+	if (!res) 
+		return -EINVAL;
+	printk("numtasks config='%s'\n",cfgstr);
+	return 0;
+}
+
+static void
+numtasks_change_resclass(void *task, void *old, void *new)
+{
+	ckrm_numtasks_t *oldres = old;
+	ckrm_numtasks_t *newres = new;
+
+	if (oldres != (void *) -1) {
+		struct task_struct *tsk = task;
+		if (!oldres) {
+			struct ckrm_core_class *old_core = &(tsk->parent->taskclass->core);
+			oldres = ckrm_get_res_class(old_core, numtasks_rcbs.resid,
+					ckrm_numtasks_t);
+		}
+		numtasks_put_ref(oldres->core);
+	}
+	if (newres) {
+		(void) numtasks_get_ref(newres->core, 1);
+	}
+}
+
+struct ckrm_res_ctlr numtasks_rcbs = {
+	.res_name          = NUMTASKS_NAME,
+	.res_hdepth        = 1,
+	.resid             = -1,
+	.res_alloc         = numtasks_res_alloc,
+	.res_free          = numtasks_res_free,
+	.set_share_values  = numtasks_set_share_values,
+	.get_share_values  = numtasks_get_share_values,
+	.get_stats         = numtasks_get_stats,
+	.show_config       = numtasks_show_config,
+	.set_config        = numtasks_set_config,
+	.change_resclass   = numtasks_change_resclass,
+};
+
+int __init
+init_ckrm_numtasks_res(void)
+{
+	struct ckrm_classtype *clstype;
+	int resid = numtasks_rcbs.resid;
+
+	clstype = ckrm_find_classtype_by_name("taskclass");
+	if (clstype == NULL) {
+		printk(KERN_INFO " Unknown ckrm classtype<taskclass>");
+		return -ENOENT;
+	}
+
+	if (resid == -1) {
+		resid = ckrm_register_res_ctlr(clstype,&numtasks_rcbs);
+		printk("........init_ckrm_numtasks_res -> %d\n",resid);
+	}
+	return 0;
+}	
+
+void __exit
+exit_ckrm_numtasks_res(void)
+{
+	ckrm_unregister_res_ctlr(&numtasks_rcbs);
+	numtasks_rcbs.resid = -1;
+}
+
+module_init(init_ckrm_numtasks_res)
+module_exit(exit_ckrm_numtasks_res)
+
+EXPORT_SYMBOL(numtasks_get_ref);
+EXPORT_SYMBOL(numtasks_put_ref);
+
+MODULE_LICENSE("GPL");
+