This patch provides the extensions for CKRM to track task classes.
 This is the base to enable task class based resource control for
 cpu, memory and disk I/O.

Signed-Off-By: Chandra Seetharaman <[EMAIL PROTECTED]>
Signed-Off-By: Hubertus Franke <[EMAIL PROTECTED]>
Signed-Off-By: Shailabh Nagar <[EMAIL PROTECTED]>
Signed-Off-By: Vivek Kashyap <[EMAIL PROTECTED]>
Signed-Off-By: Gerrit Huizenga <[EMAIL PROTECTED]>
Signed-off-by: Nishanth Aravamudan <[EMAIL PROTECTED]>


Index: linux-2.6.12-rc1/fs/rcfs/Makefile
===================================================================
--- linux-2.6.12-rc1.orig/fs/rcfs/Makefile      2005-03-18 15:16:29.721772974 
-0800
+++ linux-2.6.12-rc1/fs/rcfs/Makefile   2005-03-18 15:16:33.370482769 -0800
@@ -5,3 +5,4 @@
 obj-$(CONFIG_RCFS_FS) += rcfs.o 
 
 rcfs-y := super.o inode.o dir.o rootdir.o magic.o
+rcfs-$(CONFIG_CKRM_TYPE_TASKCLASS) += tc_magic.o
Index: linux-2.6.12-rc1/fs/rcfs/rootdir.c
===================================================================
--- linux-2.6.12-rc1.orig/fs/rcfs/rootdir.c     2005-03-18 15:16:29.721772974 
-0800
+++ linux-2.6.12-rc1/fs/rcfs/rootdir.c  2005-03-18 15:16:33.372482610 -0800
@@ -58,7 +58,7 @@ int rcfs_unregister_engine(struct rbce_e
        return 0;
 }
 
-EXPORT_SYMBOL(rcfs_unregister_engine);
+EXPORT_SYMBOL_GPL(rcfs_unregister_engine);
 
 /*
  * rcfs_mkroot
@@ -183,6 +183,10 @@ int rcfs_deregister_classtype(struct ckr
 
 EXPORT_SYMBOL_GPL(rcfs_deregister_classtype);
 
+#ifdef CONFIG_CKRM_TYPE_TASKCLASS
+extern struct rcfs_mfdesc tc_mfdesc;
+#endif
+
 /* Common root and magic file entries.
  * root name, root permissions, magic file names and magic file permissions 
  * are needed by all entities (classtypes and classification engines) existing 
@@ -193,6 +197,10 @@ EXPORT_SYMBOL_GPL(rcfs_deregister_classt
  * table to initialize their magf entries. 
  */
 
-struct rcfs_mfdesc *genmfdesc[] = {
+struct rcfs_mfdesc *genmfdesc[CKRM_MAX_CLASSTYPES] = {
+#ifdef CONFIG_CKRM_TYPE_TASKCLASS
+       &tc_mfdesc,
+#else
        NULL,
+#endif
 };
Index: linux-2.6.12-rc1/fs/rcfs/tc_magic.c
===================================================================
--- /dev/null   1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.12-rc1/fs/rcfs/tc_magic.c 2005-03-18 15:16:33.373482530 -0800
@@ -0,0 +1,93 @@
+/* 
+ * fs/rcfs/tc_magic.c 
+ *
+ * Copyright (C) Shailabh Nagar,      IBM Corp. 2004
+ *           (C) Vivek Kashyap,       IBM Corp. 2004
+ *           (C) Chandra Seetharaman, IBM Corp. 2004
+ *           (C) Hubertus Franke,     IBM Corp. 2004
+ *           
+ * define magic fileops for taskclass classtype
+ *
+ * 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.
+ */
+
+#include <linux/rcfs.h>
+#include <linux/ckrm_tc.h>
+
+/*
+ * Taskclass general
+ *
+ * Define structures for taskclass root directory and its magic files 
+ * In taskclasses, there is one set of magic files, created automatically under
+ * the taskclass root (upon classtype registration) and each directory (class) 
+ * created subsequently. However, classtypes can also choose to have different 
+ * sets of magic files created under their root and other directories under 
+ * root using their mkdir function. RCFS only provides helper functions for 
+ * creating the root directory and its magic files
+ * 
+ */
+
+#define TC_FILE_MODE (S_IFREG | S_IRUGO | S_IWUSR)
+
+#define NR_TCROOTMF  7
+struct rcfs_magf tc_rootdesc[NR_TCROOTMF] = {
+       /* First entry must be root */
+       {
+       /* .name = should not be set, copy from classtype name */
+        .mode = RCFS_DEFAULT_DIR_MODE,
+        .i_op = &rcfs_dir_inode_operations,
+        .i_fop = &simple_dir_operations,
+        },
+       /* Rest are root's magic files */
+       {
+        .name = "target",
+        .mode = TC_FILE_MODE,
+        .i_fop = &target_fileops,
+        .i_op = &rcfs_file_inode_operations,
+        },
+       {
+        .name = "members",
+        .mode = TC_FILE_MODE,
+        .i_fop = &members_fileops,
+        .i_op = &rcfs_file_inode_operations,
+        },
+       {
+        .name = "stats",
+        .mode = TC_FILE_MODE,
+        .i_fop = &stats_fileops,
+        .i_op = &rcfs_file_inode_operations,
+        },
+       {
+        .name = "shares",
+        .mode = TC_FILE_MODE,
+        .i_fop = &shares_fileops,
+        .i_op = &rcfs_file_inode_operations,
+        },
+       /*
+        * Reclassify and Config should be made available only at the 
+        * root level. Make sure they are the last two entries, as 
+        * rcfs_mkdir depends on it.
+        */
+       {
+        .name = "reclassify",
+        .mode = TC_FILE_MODE,
+        .i_fop = &reclassify_fileops,
+        .i_op = &rcfs_file_inode_operations,
+        },
+       {
+        .name = "config",
+        .mode = TC_FILE_MODE,
+        .i_fop = &config_fileops,
+        .i_op = &rcfs_file_inode_operations,
+        },
+};
+
+struct rcfs_mfdesc tc_mfdesc = {
+       .rootmf = tc_rootdesc,
+       .rootmflen = NR_TCROOTMF,
+};
Index: linux-2.6.12-rc1/include/linux/ckrm_tc.h
===================================================================
--- /dev/null   1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.12-rc1/include/linux/ckrm_tc.h    2005-03-18 15:16:33.374482451 
-0800
@@ -0,0 +1,46 @@
+/* ckrm_tc.h - Header file to be used by task class users
+ *
+ * Copyright (C) Hubertus Franke, IBM Corp. 2003, 2004
+ * 
+ * Provides data structures, macros and kernel API for the 
+ * classtype, taskclass.
+ *
+ * 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 version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#ifndef _LINUX_CKRM_TC_H_
+#define _LINUX_CKRM_TC_H_
+
+#ifdef CONFIG_CKRM_TYPE_TASKCLASS
+#include <linux/ckrm_rc.h>
+
+#define TASK_CLASS_TYPE_NAME "taskclass"
+
+struct ckrm_task_class {
+       struct ckrm_core_class core;
+};
+
+/*
+ * Index into genmfdesc array, defined in rcfs/dir_modules.c,
+ * which has the mfdesc entry that taskclass wants to use.
+ */
+#define TC_MF_IDX  0
+
+extern int ckrm_forced_reclassify_pid(int, struct ckrm_task_class *);
+
+#else /* CONFIG_CKRM_TYPE_TASKCLASS */
+
+#define ckrm_forced_reclassify_pid(a, b) (0)
+
+#endif
+
+#endif /* _LINUX_CKRM_TC_H_ */
Index: linux-2.6.12-rc1/include/linux/sched.h
===================================================================
--- linux-2.6.12-rc1.orig/include/linux/sched.h 2005-03-18 15:16:24.338201164 
-0800
+++ linux-2.6.12-rc1/include/linux/sched.h      2005-03-18 15:16:33.375482371 
-0800
@@ -728,14 +728,17 @@ struct task_struct {
        nodemask_t mems_allowed;
        int cpuset_mems_generation;
 #endif
-#ifdef CONFIG_DELAY_ACCT
-       struct task_delay_info delays;
-#endif
 #ifdef CONFIG_CKRM
        spinlock_t  ckrm_tsklock;
        void       *ce_data;
+#ifdef CONFIG_CKRM_TYPE_TASKCLASS
+       struct ckrm_task_class *taskclass;
+       struct list_head taskclass_link;
+#endif /* CONFIG_CKRM_TYPE_TASKCLASS */
+#endif /* CONFIG_CKRM */
+#ifdef CONFIG_DELAY_ACCT
+       struct task_delay_info delays;
 #endif
-
 };
 
 static inline pid_t process_group(struct task_struct *tsk)
Index: linux-2.6.12-rc1/init/Kconfig
===================================================================
--- linux-2.6.12-rc1.orig/init/Kconfig  2005-03-18 15:16:29.724772736 -0800
+++ linux-2.6.12-rc1/init/Kconfig       2005-03-18 15:16:33.376482292 -0800
@@ -162,6 +162,18 @@ config RCFS_FS
          
          Say M if unsure, Y to save on module loading. N doesn't make sense 
          when CKRM has been configured.
+
+config CKRM_TYPE_TASKCLASS
+       bool "Class Manager for Task Groups"
+       depends on CKRM && RCFS_FS
+       default y
+       help
+         TASKCLASS provides the extensions for CKRM to track task classes
+         This is the base to enable task class based resource control for
+         cpu, memory and disk I/O.
+       
+         Say Y if unsure 
+
 endmenu
 
 config SYSCTL
Index: linux-2.6.12-rc1/kernel/ckrm/ckrm_tc.c
===================================================================
--- /dev/null   1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.12-rc1/kernel/ckrm/ckrm_tc.c      2005-03-18 15:16:33.378482133 
-0800
@@ -0,0 +1,745 @@
+/* ckrm_tc.c - Class-based Kernel Resource Management (CKRM)
+ *
+ * Copyright (C) Hubertus Franke, IBM Corp. 2003,2004
+ *           (C) Shailabh Nagar,  IBM Corp. 2003
+ *           (C) Chandra Seetharaman,  IBM Corp. 2003
+ *          (C) Vivek Kashyap, IBM Corp. 2004
+ * 
+ * 
+ * Provides kernel API of CKRM for in-kernel,per-resource controllers 
+ * (one each for cpu, memory, io, network) and callbacks for 
+ * classification modules.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <asm/uaccess.h>
+#include <linux/mm.h>
+#include <asm/errno.h>
+#include <linux/string.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/ckrm_rc.h>
+
+#include <linux/ckrm_tc.h>
+
+static struct ckrm_task_class taskclass_dflt_class = {
+};
+
+const char *dflt_taskclass_name = TASK_CLASS_TYPE_NAME;
+
+static struct ckrm_core_class *ckrm_alloc_task_class(struct ckrm_core_class
+                                                    *parent, const char *name);
+static int ckrm_free_task_class(struct ckrm_core_class *core);
+
+static int tc_forced_reclassify(struct ckrm_core_class * target,
+                               const char *resname);
+static int tc_show_members(struct ckrm_core_class *core, struct seq_file *seq);
+static void tc_add_resctrl(struct ckrm_core_class *core, int resid);
+
+struct ckrm_classtype ct_taskclass = {
+       .mfidx = TC_MF_IDX,
+       .name = TASK_CLASS_TYPE_NAME,
+       .type_id = CKRM_CLASSTYPE_TASK_CLASS,
+       .maxdepth = 3,          /* starting point */
+       .resid_reserved = 4,
+       .max_res_ctlrs = CKRM_MAX_RES_CTLRS,
+       .max_resid = 0,
+       .bit_res_ctlrs = 0L,
+       .res_ctlrs_lock = SPIN_LOCK_UNLOCKED,
+       .classes = LIST_HEAD_INIT(ct_taskclass.classes),
+
+       .default_class = &taskclass_dflt_class.core,
+
+       /* private version of functions */
+       .alloc = &ckrm_alloc_task_class,
+       .free = &ckrm_free_task_class,
+       .show_members = &tc_show_members,
+       .forced_reclassify = &tc_forced_reclassify,
+
+       /* use of default functions */
+       .show_shares = &ckrm_class_show_shares,
+       .show_stats = &ckrm_class_show_stats,
+       .show_config = &ckrm_class_show_config,
+       .set_config = &ckrm_class_set_config,
+       .set_shares = &ckrm_class_set_shares,
+       .reset_stats = &ckrm_class_reset_stats,
+
+       /* mandatory private version; no default available */
+       .add_resctrl = &tc_add_resctrl,
+};
+
+/*
+ * Change the task class of the given task.
+ *
+ * Change the task's task class  to "newcls" if the task's current 
+ * class (task->taskclass) is same as given "oldcls", if it is non-NULL.
+ *
+ * Caller is responsible to make sure the task structure stays put through
+ * this function.
+ *
+ * This function should be called with the following locks NOT held
+ *     - tsk->ckrm_tsklock
+ *     - core->ckrm_lock, if core is NULL then ckrm_dflt_class.ckrm_lock
+ *     - tsk->taskclass->ckrm_lock 
+ * 
+ * Function is also called with a ckrm_core_grab on the new core, hence
+ * it needs to be dropped if no assignment takes place.
+ */
+static void
+ckrm_set_taskclass(struct task_struct *tsk, struct ckrm_task_class *newcls,
+                  struct ckrm_task_class *oldcls, enum ckrm_event event)
+{
+       int i;
+       struct ckrm_classtype *clstype;
+       struct ckrm_res_ctlr *rcbs;
+       struct ckrm_task_class *curcls;
+       void *old_res_class, *new_res_class;
+       int drop_old_cls;
+
+       spin_lock(&tsk->ckrm_tsklock);
+       curcls = tsk->taskclass;
+
+       if ((void *)-1 == curcls) {
+               /* task is disassociated from ckrm.  Don't bother it. */
+               spin_unlock(&tsk->ckrm_tsklock);
+               ckrm_core_drop(class_core(newcls));
+               return;
+       }
+
+       if ((curcls == NULL) && (newcls == (void *)-1)) {
+               /*
+                * Task needs to disassociated from ckrm and has no circles
+                * just disassociate and return.
+                */
+               tsk->taskclass = newcls;
+               spin_unlock(&tsk->ckrm_tsklock);
+               return;
+       }
+       if (oldcls && (oldcls != curcls)) {
+               spin_unlock(&tsk->ckrm_tsklock);
+               if (newcls) {
+                       /* compensate for previous grab */
+                       pr_debug("(%s:%d): Race-condition caught <%s> %d\n",
+                                tsk->comm, tsk->pid, class_core(newcls)->name,
+                                event);
+                       ckrm_core_drop(class_core(newcls));
+               }
+               return;
+       }
+       /* Make sure we have a real destination core. */
+       if (!newcls) {
+               newcls = &taskclass_dflt_class;
+               ckrm_core_grab(class_core(newcls));
+       }
+       /* Take out of old class and drop the oldcore. */
+       if ((drop_old_cls = (curcls != NULL))) {
+               class_lock(class_core(curcls));
+               if (newcls == curcls) {
+                       /*
+                        * We are already in the destination class.
+                        * we still need to drop oldcore.
+                        */
+                       class_unlock(class_core(curcls));
+                       spin_unlock(&tsk->ckrm_tsklock);
+                       goto out;
+               }
+               list_del(&tsk->taskclass_link);
+               INIT_LIST_HEAD(&tsk->taskclass_link);
+               tsk->taskclass = NULL;
+               class_unlock(class_core(curcls));
+               if (newcls == (void *)-1) {
+                       tsk->taskclass = newcls;
+                       spin_unlock(&tsk->ckrm_tsklock);
+
+                       /* still need to get out of old class. */
+                       newcls = NULL;
+                       goto rc_handling;
+               }
+       }
+       /* put into new class */
+       class_lock(class_core(newcls));
+       tsk->taskclass = newcls;
+       list_add(&tsk->taskclass_link, &class_core(newcls)->objlist);
+       class_unlock(class_core(newcls));
+
+       if (newcls == curcls) {
+               spin_unlock(&tsk->ckrm_tsklock);
+               goto out;
+       }
+
+       CE_NOTIFY(&ct_taskclass, event, newcls, tsk);
+
+       spin_unlock(&tsk->ckrm_tsklock);
+
+      rc_handling:
+       clstype = &ct_taskclass;
+       if (clstype->bit_res_ctlrs) {   
+               /* avoid running through the entire list if none are registered 
*/
+               for (i = 0; i < clstype->max_resid; i++) {
+                       if (clstype->res_ctlrs[i] == NULL)
+                               continue;
+                       atomic_inc(&clstype->nr_resusers[i]);
+                       old_res_class =
+                           curcls ? class_core(curcls)->res_class[i] : NULL;
+                       new_res_class =
+                           newcls ? class_core(newcls)->res_class[i] : NULL;
+                       rcbs = clstype->res_ctlrs[i];
+                       if (rcbs && rcbs->change_resclass
+                           && (old_res_class != new_res_class))
+                               (*rcbs->change_resclass) (tsk, old_res_class,
+                                                         new_res_class);
+                       atomic_dec(&clstype->nr_resusers[i]);
+               }
+       }
+
+      out:
+       if (drop_old_cls)
+               ckrm_core_drop(class_core(curcls));
+       return;
+}
+
+static void tc_add_resctrl(struct ckrm_core_class *core, int resid)
+{
+       struct task_struct *tsk;
+       struct ckrm_res_ctlr *rcbs;
+
+       if ((resid < 0) || (resid >= CKRM_MAX_RES_CTLRS)
+           || ((rcbs = core->classtype->res_ctlrs[resid]) == NULL))
+               return;
+
+       class_lock(core);
+       list_for_each_entry(tsk, &core->objlist, taskclass_link) {
+               if (rcbs->change_resclass)
+                       (*rcbs->change_resclass) (tsk, (void *)-1,
+                                                 core->res_class[resid]);
+       }
+       class_unlock(core);
+}
+
+/**************************************************************************
+ *                   Functions called from classification points          *
+ **************************************************************************/
+
+#define CE_CLASSIFY_TASK(event, tsk)                                   \
+do {                                                                   \
+       struct ckrm_task_class *newcls = NULL;                          \
+       struct ckrm_task_class *oldcls = tsk->taskclass;                \
+                                                                       \
+       CE_CLASSIFY_RET(newcls,&ct_taskclass,event,tsk);                \
+       if (newcls) {                                                   \
+               /* called synchrously. no need to get task struct */    \
+               ckrm_set_taskclass(tsk, newcls, oldcls, event);         \
+       }                                                               \
+} while (0)
+
+
+#define CE_CLASSIFY_TASK_PROTECT(event, tsk)   \
+do {                                           \
+       ce_protect(&ct_taskclass);              \
+       CE_CLASSIFY_TASK(event,tsk);            \
+       ce_release(&ct_taskclass);              \
+} while (0)
+
+static void cb_taskclass_newtask(struct task_struct *tsk)
+{
+       tsk->taskclass = NULL;
+       INIT_LIST_HEAD(&tsk->taskclass_link);
+}
+
+static void cb_taskclass_fork(struct task_struct *tsk)
+{
+       struct ckrm_task_class *cls = NULL;
+
+       pr_debug("%p:%d:%s\n", tsk, tsk->pid, tsk->comm);
+
+       ce_protect(&ct_taskclass);
+       CE_CLASSIFY_RET(cls, &ct_taskclass, CKRM_EVENT_FORK, tsk);
+       if (cls == NULL) {
+               spin_lock(&tsk->parent->ckrm_tsklock);
+               cls = tsk->parent->taskclass;
+               ckrm_core_grab(class_core(cls));
+               spin_unlock(&tsk->parent->ckrm_tsklock);
+       }
+       if (!list_empty(&tsk->taskclass_link))
+               pr_debug("cb_taskclass_fork: BUG in cb_fork.. tsk (%s:%d> 
already linked\n",
+                      tsk->comm, tsk->pid);
+
+       ckrm_set_taskclass(tsk, cls, NULL, CKRM_EVENT_FORK);
+       ce_release(&ct_taskclass);
+}
+
+static void cb_taskclass_exit(struct task_struct *tsk)
+{
+       CE_CLASSIFY_NORET(&ct_taskclass, CKRM_EVENT_EXIT, tsk);
+       ckrm_set_taskclass(tsk, (void *)-1, NULL, CKRM_EVENT_EXIT);
+}
+
+static void cb_taskclass_exec(const char *filename)
+{
+       pr_debug("%p:%d:%s <%s>\n", current, current->pid, current->comm,
+                  filename);
+       CE_CLASSIFY_TASK_PROTECT(CKRM_EVENT_EXEC, current);
+}
+
+static void cb_taskclass_uid(void)
+{
+       pr_debug("%p:%d:%s\n", current, current->pid, current->comm);
+       CE_CLASSIFY_TASK_PROTECT(CKRM_EVENT_UID, current);
+}
+
+static void cb_taskclass_gid(void)
+{
+       pr_debug("%p:%d:%s\n", current, current->pid, current->comm);
+       CE_CLASSIFY_TASK_PROTECT(CKRM_EVENT_GID, current);
+}
+
+static struct ckrm_event_spec taskclass_events_callbacks[] = {
+       {CKRM_EVENT_NEWTASK, { cb_taskclass_newtask, NULL}},
+       {CKRM_EVENT_EXEC, { cb_taskclass_exec, NULL }},
+       {CKRM_EVENT_FORK, { cb_taskclass_fork, NULL }},
+       {CKRM_EVENT_EXIT, { cb_taskclass_exit, NULL }},
+       {CKRM_EVENT_UID, { cb_taskclass_uid, NULL }},
+       {CKRM_EVENT_GID, { cb_taskclass_gid, NULL }},
+       {-1, { -1, NULL }}
+};
+
+/*
+ * Asynchronous callback functions   (driven by RCFS)
+ * 
+ *    Async functions force a setting of the task structure
+ *    synchronous callbacks are protected against race conditions 
+ *    by using a cmpxchg on the core before setting it.
+ *    Async calls need to be serialized to ensure they can't 
+ *    race against each other 
+ */
+
+static DECLARE_MUTEX(ckrm_async_serializer);   /* serialize all async 
functions */
+
+/*
+ * Go through the task list and reclassify all tasks according to the current
+ * classification rules.
+ *
+ * We have the problem that we can not hold any lock (including the 
+ * tasklist_lock) while classifying. Two methods possible
+ *
+ * (a) go through entire pidrange (0..pidmax) and if a task exists at 
+ *     that pid then reclassify it
+ * (b) go several time through task list and build a bitmap for a particular 
+ *     subrange of pid otherwise the memory requirements ight be too much.
+ * 
+ * We use a hybrid by comparing ratio nr_threads/pidmax
+ */
+
+static int ckrm_reclassify_all_tasks(void)
+{
+       extern int pid_max;
+
+       struct task_struct *proc, *thread;
+       int i;
+       int curpidmax = pid_max;
+       int ratio;
+       int use_bitmap;
+
+       /* Check permissions */
+       if ((!capable(CAP_SYS_NICE)) && (!capable(CAP_SYS_RESOURCE))) {
+               return -EPERM;
+       }
+
+       ratio = curpidmax / nr_threads;
+       if (curpidmax <= PID_MAX_DEFAULT) {
+               use_bitmap = 1;
+       } else {
+               use_bitmap = (ratio >= 2);
+       }
+
+       ce_protect(&ct_taskclass);
+
+      retry:
+
+       if (use_bitmap == 0) {
+               /* Go through it in one walk. */
+               read_lock(&tasklist_lock);
+               for (i = 0; i < curpidmax; i++) {
+                       if ((thread = find_task_by_pid(i)) == NULL)
+                               continue;
+                       get_task_struct(thread);
+                       read_unlock(&tasklist_lock);
+                       CE_CLASSIFY_TASK(CKRM_EVENT_RECLASSIFY, thread);
+                       put_task_struct(thread);
+                       read_lock(&tasklist_lock);
+               }
+               read_unlock(&tasklist_lock);
+       } else {
+               unsigned long *bitmap;
+               int bitmapsize;
+               int order = 0;
+               int num_loops;
+               int pid, do_next;
+
+               bitmap = (unsigned long *)__get_free_pages(GFP_KERNEL, order);
+               if (bitmap == NULL) {
+                       use_bitmap = 0;
+                       goto retry;
+               }
+
+               bitmapsize = 8 * (1 << (order + PAGE_SHIFT));
+               num_loops = (curpidmax + bitmapsize - 1) / bitmapsize;
+
+               do_next = 1;
+               for (i = 0; i < num_loops && do_next; i++) {
+                       int pid_start = i * bitmapsize;
+                       int pid_end = pid_start + bitmapsize;
+                       int num_found = 0;
+                       int pos;
+
+                       memset(bitmap, 0, bitmapsize / 8);      /* start afresh 
*/
+                       do_next = 0;
+
+                       read_lock(&tasklist_lock);
+                       do_each_thread(proc, thread) {
+                               pid = thread->pid;
+                               if ((pid < pid_start) || (pid >= pid_end)) {
+                                       if (pid >= pid_end) {
+                                               do_next = 1;
+                                       }
+                                       continue;
+                               }
+                               pid -= pid_start;
+                               set_bit(pid, bitmap);
+                               num_found++;
+                       }
+                       while_each_thread(proc, thread);
+                       read_unlock(&tasklist_lock);
+
+                       if (num_found == 0)
+                               continue;
+
+                       pos = 0;
+                       for (; num_found--;) {
+                               pos = find_next_bit(bitmap, bitmapsize, pos);
+                               pid = pos + pid_start;
+
+                               read_lock(&tasklist_lock);
+                               if ((thread = find_task_by_pid(pid)) != NULL) {
+                                       get_task_struct(thread);
+                                       read_unlock(&tasklist_lock);
+                                       CE_CLASSIFY_TASK(CKRM_EVENT_RECLASSIFY,
+                                                        thread);
+                                       put_task_struct(thread);
+                               } else {
+                                       read_unlock(&tasklist_lock);
+                               }
+                               pos++;
+                       }
+               }
+
+       }
+       ce_release(&ct_taskclass);
+       return 0;
+}
+
+/*
+ * Reclassify all tasks in the given core class.
+ */
+
+static void ckrm_reclassify_class_tasks(struct ckrm_task_class *cls)
+{
+       int ce_regd;
+       struct ckrm_hnode *cnode;
+       struct ckrm_task_class *parcls;
+       int num = 0;
+
+       if (!ckrm_validate_and_grab_core(&cls->core))
+               return;
+
+       down(&ckrm_async_serializer);
+       pr_debug("start %p:%s:%d:%d\n", cls, cls->core.name,
+                atomic_read(&cls->core.refcnt),
+                atomic_read(&cls->core.hnode.parent->refcnt));
+       /*
+        * If no CE registered for this classtype, following will be needed 
+        * repeatedly.
+        */
+       ce_regd = atomic_read(&class_core(cls)->classtype->ce_regd);
+       cnode = &(class_core(cls)->hnode);
+       parcls = class_type(struct ckrm_task_class, cnode->parent);
+
+      next_task:
+       class_lock(class_core(cls));
+       if (!list_empty(&class_core(cls)->objlist)) {
+               struct ckrm_task_class *newcls = NULL;
+               struct task_struct *tsk =
+                   list_entry(class_core(cls)->objlist.next,
+                              struct task_struct, taskclass_link);
+
+               get_task_struct(tsk);
+               class_unlock(class_core(cls));
+
+               if (ce_regd) {
+                       CE_CLASSIFY_RET(newcls, &ct_taskclass,
+                                       CKRM_EVENT_RECLASSIFY, tsk);
+                       if (cls == newcls) {
+                               /*
+                                * Don't allow reclassifying to the same class
+                                * as we are in the process of cleaning up 
+                                * this class
+                                */
+
+                               /* compensate for CE's grab */
+                               ckrm_core_drop(class_core(newcls));     
+                               newcls = NULL;
+                       }
+               }
+               if (newcls == NULL) {
+                       newcls = parcls;
+                       ckrm_core_grab(class_core(newcls));
+               }
+               ckrm_set_taskclass(tsk, newcls, cls, CKRM_EVENT_RECLASSIFY);
+               put_task_struct(tsk);
+               num++;
+               goto next_task;
+       }
+       pr_debug("stop  %p:%s:%d:%d   %d\n", cls, cls->core.name,
+                atomic_read(&cls->core.refcnt),
+                atomic_read(&cls->core.hnode.parent->refcnt), num);
+       class_unlock(class_core(cls));
+       ckrm_core_drop(class_core(cls));
+
+       up(&ckrm_async_serializer);
+
+       return;
+}
+
+/*
+ * Change the core class of the given task
+ */
+
+int ckrm_forced_reclassify_pid(pid_t pid, struct ckrm_task_class *cls)
+{
+       struct task_struct *tsk;
+
+       if (cls && !ckrm_validate_and_grab_core(class_core(cls)))
+               return -EINVAL;
+
+       read_lock(&tasklist_lock);
+       if ((tsk = find_task_by_pid(pid)) == NULL) {
+               read_unlock(&tasklist_lock);
+               if (cls) 
+                       ckrm_core_drop(class_core(cls));
+               return -EINVAL;
+       }
+       get_task_struct(tsk);
+       read_unlock(&tasklist_lock);
+
+       /* Check permissions */
+       if ((!capable(CAP_SYS_NICE)) &&
+           (!capable(CAP_SYS_RESOURCE)) && (current->user != tsk->user)) {
+               if (cls) 
+                       ckrm_core_drop(class_core(cls));
+               put_task_struct(tsk);
+               return -EPERM;
+       }
+
+       ce_protect(&ct_taskclass);
+       if (cls == NULL)
+               CE_CLASSIFY_TASK(CKRM_EVENT_RECLASSIFY,tsk);
+       else 
+               ckrm_set_taskclass(tsk, cls, NULL, CKRM_EVENT_MANUAL);
+
+       ce_release(&ct_taskclass);
+       put_task_struct(tsk);
+
+       return 0;
+}
+
+static struct ckrm_core_class *ckrm_alloc_task_class(struct ckrm_core_class
+                                                    *parent, const char *name)
+{
+       struct ckrm_task_class *taskcls;
+       taskcls = kmalloc(sizeof(struct ckrm_task_class), GFP_KERNEL);
+       if (taskcls == NULL)
+               return NULL;
+       memset(taskcls, 0, sizeof(struct ckrm_task_class));
+
+       ckrm_init_core_class(&ct_taskclass, class_core(taskcls), parent, name);
+
+       ce_protect(&ct_taskclass);
+       if (ct_taskclass.ce_cb_active && ct_taskclass.ce_callbacks.class_add)
+               (*ct_taskclass.ce_callbacks.class_add) (name, taskcls,
+                                                       ct_taskclass.type_id);
+       ce_release(&ct_taskclass);
+
+       return class_core(taskcls);
+}
+
+static int ckrm_free_task_class(struct ckrm_core_class *core)
+{
+       struct ckrm_task_class *taskcls;
+
+       if (!ckrm_is_core_valid(core)) {
+               return (-EINVAL);               /* Invalid core */
+       }
+       if (core == core->classtype->default_class) {
+               /* reset the name tag */
+               core->name = dflt_taskclass_name;
+               return 0;
+       }
+
+       pr_debug("%p:%s:%d\n", core, core->name, atomic_read(&core->refcnt));
+
+       taskcls = class_type(struct ckrm_task_class, core);
+
+       ce_protect(&ct_taskclass);
+
+       if (ct_taskclass.ce_cb_active && ct_taskclass.ce_callbacks.class_delete)
+               (*ct_taskclass.ce_callbacks.class_delete) (core->name, taskcls,
+                                                          
ct_taskclass.type_id);
+       ckrm_reclassify_class_tasks(taskcls);
+
+       ce_release(&ct_taskclass);
+
+       ckrm_release_core_class(core);  
+       return 0;
+}
+
+void __init ckrm_meta_init_taskclass(void)
+{
+       pr_debug("...... Initializing ClassType<%s> ........\n",
+              ct_taskclass.name);
+       /* intialize the default class */
+       ckrm_init_core_class(&ct_taskclass, class_core(&taskclass_dflt_class),
+                            NULL, dflt_taskclass_name);
+
+       /* register classtype and initialize default task class */
+       ckrm_register_classtype(&ct_taskclass);
+       ckrm_register_event_set(taskclass_events_callbacks);
+
+       /*
+        * note registeration of all resource controllers will be done 
+        * later dynamically as these are specified as modules
+        */
+}
+
+static int tc_show_members(struct ckrm_core_class *core, struct seq_file *seq)
+{
+       struct list_head *lh;
+       struct task_struct *tsk;
+
+       class_lock(core);
+       list_for_each(lh, &core->objlist) {
+               tsk = container_of(lh, struct task_struct, taskclass_link);
+               seq_printf(seq, "%ld\n", (long)tsk->pid);
+       }
+       class_unlock(core);
+
+       return 0;
+}
+
+static int tc_forced_reclassify(struct ckrm_core_class *target, const char 
*obj)
+{
+       pid_t pid;
+       int rc = -EINVAL;
+
+       pid = (pid_t) simple_strtol(obj, NULL, 0);
+
+       down(&ckrm_async_serializer);   /* protect against race with 
reclassify_class */
+       if (pid < 0) {
+               /* TBD: We could treat this as a process group. */
+               rc = -EINVAL;
+       } else if (pid == 0) {
+               rc = (target == NULL) ? ckrm_reclassify_all_tasks() : -EINVAL;
+       } else {
+               struct ckrm_task_class *cls = NULL;
+               if (target) 
+                       cls = class_type(struct ckrm_task_class, target);
+               rc = ckrm_forced_reclassify_pid(pid,cls);
+       }
+       up(&ckrm_async_serializer);
+       return rc;
+}
+
+#if 0
+
+/******************************************************************************
+ * Debugging Task Classes:  Utility functions
+ 
******************************************************************************/
+
+void check_tasklist_sanity(struct ckrm_task_class *cls)
+{
+       struct ckrm_core_class *core = class_core(cls);
+       struct list_head *lh1, *lh2;
+       int count = 0;
+
+       if (core) {
+               class_lock(core);
+               if (list_empty(&core->objlist)) {
+                       class_lock(core);
+                       pr_debug("check_tasklist_sanity: class %s empty list\n",
+                              core->name);
+                       return;
+               }
+               list_for_each_safe(lh1, lh2, &core->objlist) {
+                       struct task_struct *tsk =
+                           container_of(lh1, struct task_struct,
+                                        taskclass_link);
+                       if (count++ > 20000) {
+                               pr_debug("check_tasklist_sanity: CKRM taskclass 
list is CORRUPTED\n");
+                               break;
+                       }
+                       if (tsk->taskclass != cls) {
+                               const char *tclsname;
+                               tclsname = (tsk->taskclass) ? 
+                                       class_core(tsk->taskclass)->name:"NULL";
+                               pr_debug("sanity: task %s:%d has ckrm_core "
+                                      "|%s| but in list |%s|\n", tsk->comm, 
+                                      tsk->pid, tclsname, core->name);
+                       }
+               }
+               class_unlock(core);
+       }
+}
+
+void ckrm_debug_free_task_class(struct ckrm_task_class *tskcls)
+{
+       struct task_struct *proc, *thread;
+       int count = 0;
+
+       pr_debug("ckrm_debug_free_task_class: Analyze Error <%s> %d\n",
+              class_core(tskcls)->name,
+              atomic_read(&(class_core(tskcls)->refcnt)));
+
+       read_lock(&tasklist_lock);
+       class_lock(class_core(tskcls));
+       do_each_thread(proc, thread) {
+               count += (tskcls == thread->taskclass);
+               if ((thread->taskclass == tskcls) || (tskcls == NULL)) {
+                       const char *tclsname;
+                       tclsname = (thread->taskclass) ? 
+                               class_core(thread->taskclass)->name :"NULL";
+                       pr_debug("ckrm-debug_free_task_class: %d thread=<%s:%d> 
 -> <%s> <%lx>\n", count,
+                              thread->comm, thread->pid, tclsname,
+                              thread->flags & PF_EXITING);
+               }
+       } while_each_thread(proc, thread);
+       class_unlock(class_core(tskcls));
+       read_unlock(&tasklist_lock);
+
+       pr_debug("ckrm_debug_free_task_class: End Analyze Error <%s> %d\n",
+              class_core(tskcls)->name,
+              atomic_read(&(class_core(tskcls)->refcnt)));
+}
+
+#endif
Index: linux-2.6.12-rc1/kernel/ckrm/Makefile
===================================================================
--- linux-2.6.12-rc1.orig/kernel/ckrm/Makefile  2005-03-18 15:16:24.341200925 
-0800
+++ linux-2.6.12-rc1/kernel/ckrm/Makefile       2005-03-18 15:16:33.379482053 
-0800
@@ -3,3 +3,4 @@
 #
 
 obj-y += ckrm_events.o ckrm.o ckrmutils.o
+obj-$(CONFIG_CKRM_TYPE_TASKCLASS) += ckrm_tc.o

--
-
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