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LU-15317 libcfs: Remove D_TTY
[fs/lustre-release.git] / libcfs / libcfs / tracefile.c
index 1478a3a..ac473c5 100644 (file)
  *
  * You should have received a copy of the GNU General Public License
  * version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
+ * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */
  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2012, 2013, Intel Corporation.
+ * Copyright (c) 2012, 2017, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
- * Lustre is a trademark of Sun Microsystems, Inc.
  *
  * libcfs/libcfs/tracefile.c
  *
  * Author: Phil Schwan <phil@clusterfs.com>
  */
 
-
 #define DEBUG_SUBSYSTEM S_LNET
-#define LUSTRE_TRACEFILE_PRIVATE
 #include "tracefile.h"
 
+#include <linux/ctype.h>
+#include <linux/fs.h>
+#include <linux/kthread.h>
+#include <linux/pagemap.h>
+#include <linux/poll.h>
+#include <linux/uaccess.h>
+#include <libcfs/linux/linux-fs.h>
 #include <libcfs/libcfs.h>
 
-/* XXX move things up to the top, comment */
-union cfs_trace_data_union (*cfs_trace_data[TCD_MAX_TYPES])[NR_CPUS] __cacheline_aligned;
+
+enum cfs_trace_buf_type {
+       CFS_TCD_TYPE_PROC = 0,
+       CFS_TCD_TYPE_SOFTIRQ,
+       CFS_TCD_TYPE_IRQ,
+       CFS_TCD_TYPE_CNT
+};
+
+union cfs_trace_data_union (*cfs_trace_data[CFS_TCD_TYPE_CNT])[NR_CPUS] __cacheline_aligned;
+
+/* Pages containing records already processed by daemon.
+ * Link via ->lru, use size in ->private
+ */
+static LIST_HEAD(daemon_pages);
+static long daemon_pages_count;
+static long daemon_pages_max;
 
 char cfs_tracefile[TRACEFILE_NAME_SIZE];
 long long cfs_tracefile_size = CFS_TRACEFILE_SIZE;
-static struct tracefiled_ctl trace_tctl;
-struct mutex cfs_trace_thread_mutex;
-static int thread_running = 0;
 
-atomic_t cfs_tage_allocated = ATOMIC_INIT(0);
+struct task_struct *tctl_task;
+
+static atomic_t cfs_tage_allocated = ATOMIC_INIT(0);
+static DECLARE_RWSEM(cfs_tracefile_sem);
+
+/* trace file lock routines */
+/* The walking argument indicates the locking comes from all tcd types
+ * iterator and we must lock it and dissable local irqs to avoid deadlocks
+ * with other interrupt locks that might be happening. See LU-1311
+ * for details.
+ */
+int cfs_trace_lock_tcd(struct cfs_trace_cpu_data *tcd, int walking)
+       __acquires(&tcd->tcd_lock)
+{
+       __LASSERT(tcd->tcd_type < CFS_TCD_TYPE_CNT);
+       if (tcd->tcd_type == CFS_TCD_TYPE_IRQ)
+               spin_lock_irqsave(&tcd->tcd_lock, tcd->tcd_lock_flags);
+       else if (tcd->tcd_type == CFS_TCD_TYPE_SOFTIRQ)
+               spin_lock_bh(&tcd->tcd_lock);
+       else if (unlikely(walking))
+               spin_lock_irq(&tcd->tcd_lock);
+       else
+               spin_lock(&tcd->tcd_lock);
+       return 1;
+}
+
+void cfs_trace_unlock_tcd(struct cfs_trace_cpu_data *tcd, int walking)
+       __releases(&tcd->tcd_lock)
+{
+       __LASSERT(tcd->tcd_type < CFS_TCD_TYPE_CNT);
+       if (tcd->tcd_type == CFS_TCD_TYPE_IRQ)
+               spin_unlock_irqrestore(&tcd->tcd_lock, tcd->tcd_lock_flags);
+       else if (tcd->tcd_type == CFS_TCD_TYPE_SOFTIRQ)
+               spin_unlock_bh(&tcd->tcd_lock);
+       else if (unlikely(walking))
+               spin_unlock_irq(&tcd->tcd_lock);
+       else
+               spin_unlock(&tcd->tcd_lock);
+}
+
+#define cfs_tcd_for_each(tcd, i, j)                                    \
+       for (i = 0; i < CFS_TCD_TYPE_CNT && cfs_trace_data[i]; i++)     \
+               for (j = 0, ((tcd) = &(*cfs_trace_data[i])[j].tcd);     \
+                    j < num_possible_cpus();                           \
+                    j++, (tcd) = &(*cfs_trace_data[i])[j].tcd)
+
+#define cfs_tcd_for_each_type_lock(tcd, i, cpu)                                \
+       for (i = 0; i < CFS_TCD_TYPE_CNT && cfs_trace_data[i] &&        \
+            (tcd = &(*cfs_trace_data[i])[cpu].tcd) &&                  \
+            cfs_trace_lock_tcd(tcd, 1); cfs_trace_unlock_tcd(tcd, 1), i++)
+
+enum cfs_trace_buf_type cfs_trace_buf_idx_get(void)
+{
+       if (in_irq())
+               return CFS_TCD_TYPE_IRQ;
+       if (in_softirq())
+               return CFS_TCD_TYPE_SOFTIRQ;
+       return CFS_TCD_TYPE_PROC;
+}
+
+static inline struct cfs_trace_cpu_data *
+cfs_trace_get_tcd(void)
+{
+       struct cfs_trace_cpu_data *tcd =
+               &(*cfs_trace_data[cfs_trace_buf_idx_get()])[get_cpu()].tcd;
+
+       cfs_trace_lock_tcd(tcd, 0);
 
-static void put_pages_on_tcd_daemon_list(struct page_collection *pc,
-                                       struct cfs_trace_cpu_data *tcd);
+       return tcd;
+}
+
+static inline void cfs_trace_put_tcd(struct cfs_trace_cpu_data *tcd)
+{
+       cfs_trace_unlock_tcd(tcd, 0);
+
+       put_cpu();
+}
 
 static inline struct cfs_trace_page *
 cfs_tage_from_list(struct list_head *list)
@@ -66,13 +150,13 @@ cfs_tage_from_list(struct list_head *list)
        return list_entry(list, struct cfs_trace_page, linkage);
 }
 
-static struct cfs_trace_page *cfs_tage_alloc(int gfp)
+static struct cfs_trace_page *cfs_tage_alloc(gfp_t gfp)
 {
        struct page            *page;
        struct cfs_trace_page *tage;
 
        /* My caller is trying to free memory */
-       if (!in_interrupt() && memory_pressure_get())
+       if (!in_interrupt() && (current->flags & PF_MEMALLOC))
                return NULL;
 
        /*
@@ -114,39 +198,19 @@ static void cfs_tage_to_tail(struct cfs_trace_page *tage,
        list_move_tail(&tage->linkage, queue);
 }
 
-int cfs_trace_refill_stock(struct cfs_trace_cpu_data *tcd, int gfp,
-                          struct list_head *stock)
-{
-       int i;
-
-       /*
-        * XXX nikita: do NOT call portals_debug_msg() (CDEBUG/ENTRY/EXIT)
-        * from here: this will lead to infinite recursion.
-        */
-
-       for (i = 0; i + tcd->tcd_cur_stock_pages < TCD_STOCK_PAGES ; ++ i) {
-               struct cfs_trace_page *tage;
-
-               tage = cfs_tage_alloc(gfp);
-               if (tage == NULL)
-                       break;
-               list_add_tail(&tage->linkage, stock);
-       }
-       return i;
-}
-
 /* return a page that has 'len' bytes left at the end */
 static struct cfs_trace_page *
 cfs_trace_get_tage_try(struct cfs_trace_cpu_data *tcd, unsigned long len)
 {
-        struct cfs_trace_page *tage;
+       struct cfs_trace_page *tage;
+       struct task_struct *tsk;
 
-        if (tcd->tcd_cur_pages > 0) {
+       if (tcd->tcd_cur_pages > 0) {
                __LASSERT(!list_empty(&tcd->tcd_pages));
-                tage = cfs_tage_from_list(tcd->tcd_pages.prev);
-               if (tage->used + len <= PAGE_CACHE_SIZE)
-                        return tage;
-        }
+               tage = cfs_tage_from_list(tcd->tcd_pages.prev);
+               if (tage->used + len <= PAGE_SIZE)
+                       return tage;
+       }
 
        if (tcd->tcd_cur_pages < tcd->tcd_max_pages) {
                if (tcd->tcd_cur_stock_pages > 0) {
@@ -156,11 +220,10 @@ cfs_trace_get_tage_try(struct cfs_trace_cpu_data *tcd, unsigned long len)
                } else {
                        tage = cfs_tage_alloc(GFP_ATOMIC);
                        if (unlikely(tage == NULL)) {
-                               if ((!memory_pressure_get() ||
+                               if ((!(current->flags & PF_MEMALLOC) ||
                                     in_interrupt()) && printk_ratelimit())
-                                       printk(KERN_WARNING
-                                              "cannot allocate a tage (%ld)\n",
-                                              tcd->tcd_cur_pages);
+                                       pr_warn("Lustre: cannot allocate a tage (%ld)\n",
+                                               tcd->tcd_cur_pages);
                                return NULL;
                        }
                }
@@ -171,16 +234,16 @@ cfs_trace_get_tage_try(struct cfs_trace_cpu_data *tcd, unsigned long len)
                list_add_tail(&tage->linkage, &tcd->tcd_pages);
                tcd->tcd_cur_pages++;
 
-               if (tcd->tcd_cur_pages > 8 && thread_running) {
-                       struct tracefiled_ctl *tctl = &trace_tctl;
+               tsk = tctl_task;
+               if (tcd->tcd_cur_pages > 8 && tsk)
                        /*
                         * wake up tracefiled to process some pages.
                         */
-                       wake_up(&tctl->tctl_waitq);
-               }
+                       wake_up_process(tsk);
+
                return tage;
-        }
-        return NULL;
+       }
+       return NULL;
 }
 
 static void cfs_tcd_shrink(struct cfs_trace_cpu_data *tcd)
@@ -196,8 +259,7 @@ static void cfs_tcd_shrink(struct cfs_trace_cpu_data *tcd)
         */
 
        if (printk_ratelimit())
-               printk(KERN_WARNING "debug daemon buffer overflowed; "
-                       "discarding 10%% of pages (%d of %ld)\n",
+               pr_warn("Lustre: debug daemon buffer overflowed; discarding 10%% of pages (%d of %ld)\n",
                        pgcount + 1, tcd->tcd_cur_pages);
 
        INIT_LIST_HEAD(&pc.pc_pages);
@@ -206,277 +268,300 @@ static void cfs_tcd_shrink(struct cfs_trace_cpu_data *tcd)
                if (pgcount-- == 0)
                        break;
 
-               list_move_tail(&tage->linkage, &pc.pc_pages);
+               list_del(&tage->linkage);
+               cfs_tage_free(tage);
                tcd->tcd_cur_pages--;
        }
-       put_pages_on_tcd_daemon_list(&pc, tcd);
 }
 
 /* return a page that has 'len' bytes left at the end */
 static struct cfs_trace_page *cfs_trace_get_tage(struct cfs_trace_cpu_data *tcd,
-                                                 unsigned long len)
+                                                unsigned long len)
 {
-        struct cfs_trace_page *tage;
+       struct cfs_trace_page *tage;
 
-        /*
-         * XXX nikita: do NOT call portals_debug_msg() (CDEBUG/ENTRY/EXIT)
-         * from here: this will lead to infinite recursion.
-         */
+       /*
+        * XXX nikita: do NOT call portals_debug_msg() (CDEBUG/ENTRY/EXIT)
+        * from here: this will lead to infinite recursion.
+        */
 
-       if (len > PAGE_CACHE_SIZE) {
-               printk(KERN_ERR
-                      "cowardly refusing to write %lu bytes in a page\n", len);
+       if (len > PAGE_SIZE) {
+               pr_err("LustreError: cowardly refusing to write %lu bytes in a page\n",
+                      len);
                return NULL;
        }
 
-        tage = cfs_trace_get_tage_try(tcd, len);
-        if (tage != NULL)
-                return tage;
-        if (thread_running)
-                cfs_tcd_shrink(tcd);
-        if (tcd->tcd_cur_pages > 0) {
-                tage = cfs_tage_from_list(tcd->tcd_pages.next);
-                tage->used = 0;
-                cfs_tage_to_tail(tage, &tcd->tcd_pages);
-        }
-        return tage;
+       tage = cfs_trace_get_tage_try(tcd, len);
+       if (tage != NULL)
+               return tage;
+       if (tctl_task)
+               cfs_tcd_shrink(tcd);
+       if (tcd->tcd_cur_pages > 0) {
+               tage = cfs_tage_from_list(tcd->tcd_pages.next);
+               tage->used = 0;
+               cfs_tage_to_tail(tage, &tcd->tcd_pages);
+       }
+       return tage;
 }
 
-int libcfs_debug_msg(struct libcfs_debug_msg_data *msgdata,
-                     const char *format, ...)
+static void cfs_set_ptldebug_header(struct ptldebug_header *header,
+                                   struct libcfs_debug_msg_data *msgdata,
+                                   unsigned long stack)
 {
-        va_list args;
-        int     rc;
+       struct timespec64 ts;
 
-        va_start(args, format);
-        rc = libcfs_debug_vmsg2(msgdata, format, args, NULL);
-        va_end(args);
+       ktime_get_real_ts64(&ts);
 
-        return rc;
+       header->ph_subsys = msgdata->msg_subsys;
+       header->ph_mask = msgdata->msg_mask;
+       header->ph_cpu_id = smp_processor_id();
+       header->ph_type = cfs_trace_buf_idx_get();
+       /* y2038 safe since all user space treats this as unsigned, but
+        * will overflow in 2106
+        */
+       header->ph_sec = (u32)ts.tv_sec;
+       header->ph_usec = ts.tv_nsec / NSEC_PER_USEC;
+       header->ph_stack = stack;
+       header->ph_pid = current->pid;
+       header->ph_line_num = msgdata->msg_line;
+       header->ph_extern_pid = 0;
 }
-EXPORT_SYMBOL(libcfs_debug_msg);
 
-int libcfs_debug_vmsg2(struct libcfs_debug_msg_data *msgdata,
-                       const char *format1, va_list args,
-                       const char *format2, ...)
+static void cfs_vprint_to_console(struct ptldebug_header *hdr, int mask,
+                                 struct va_format *vaf, const char *file,
+                                 const char *fn)
 {
-        struct cfs_trace_cpu_data *tcd = NULL;
-        struct ptldebug_header     header = {0};
-        struct cfs_trace_page     *tage;
-        /* string_buf is used only if tcd != NULL, and is always set then */
-        char                      *string_buf = NULL;
-        char                      *debug_buf;
-        int                        known_size;
-        int                        needed = 85; /* average message length */
-        int                        max_nob;
-        va_list                    ap;
-        int                        depth;
-        int                        i;
-        int                        remain;
-        int                        mask = msgdata->msg_mask;
-        char                      *file = (char *)msgdata->msg_file;
-        cfs_debug_limit_state_t   *cdls = msgdata->msg_cdls;
-
-        if (strchr(file, '/'))
-                file = strrchr(file, '/') + 1;
-
-        tcd = cfs_trace_get_tcd();
-
-        /* cfs_trace_get_tcd() grabs a lock, which disables preemption and
-         * pins us to a particular CPU.  This avoids an smp_processor_id()
-         * warning on Linux when debugging is enabled. */
-        cfs_set_ptldebug_header(&header, msgdata, CDEBUG_STACK());
-
-        if (tcd == NULL)                /* arch may not log in IRQ context */
-                goto console;
-
-        if (tcd->tcd_cur_pages == 0)
-                header.ph_flags |= PH_FLAG_FIRST_RECORD;
-
-        if (tcd->tcd_shutting_down) {
-                cfs_trace_put_tcd(tcd);
-                tcd = NULL;
-                goto console;
-        }
+       char *prefix = "Lustre";
+
+       if (hdr->ph_subsys == S_LND || hdr->ph_subsys == S_LNET)
+               prefix = "LNet";
+
+       if (mask & D_CONSOLE) {
+               if (mask & D_EMERG)
+                       pr_emerg("%sError: %pV", prefix, vaf);
+               else if (mask & D_ERROR)
+                       pr_err("%sError: %pV", prefix, vaf);
+               else if (mask & D_WARNING)
+                       pr_warn("%s: %pV", prefix, vaf);
+               else if (mask & libcfs_printk)
+                       pr_info("%s: %pV", prefix, vaf);
+       } else {
+               if (mask & D_EMERG)
+                       pr_emerg("%sError: %d:%d:(%s:%d:%s()) %pV", prefix,
+                                hdr->ph_pid, hdr->ph_extern_pid, file,
+                                hdr->ph_line_num, fn, vaf);
+               else if (mask & D_ERROR)
+                       pr_err("%sError: %d:%d:(%s:%d:%s()) %pV", prefix,
+                              hdr->ph_pid, hdr->ph_extern_pid, file,
+                              hdr->ph_line_num, fn, vaf);
+               else if (mask & D_WARNING)
+                       pr_warn("%s: %d:%d:(%s:%d:%s()) %pV", prefix,
+                               hdr->ph_pid, hdr->ph_extern_pid, file,
+                               hdr->ph_line_num, fn, vaf);
+               else if (mask & (D_CONSOLE | libcfs_printk))
+                       pr_info("%s: %pV", prefix, vaf);
+       }
+}
+
+static void cfs_print_to_console(struct ptldebug_header *hdr, int mask,
+                                const char *file, const char *fn,
+                                const char *fmt, ...)
+{
+       struct va_format vaf;
+       va_list args;
+
+       va_start(args, fmt);
+       vaf.fmt = fmt;
+       vaf.va = &args;
+       cfs_vprint_to_console(hdr, mask, &vaf, file, fn);
+}
+
+int libcfs_debug_msg(struct libcfs_debug_msg_data *msgdata,
+                    const char *format, ...)
+{
+       struct cfs_trace_cpu_data *tcd = NULL;
+       struct ptldebug_header header = {0};
+       struct cfs_trace_page *tage;
+       /* string_buf is used only if tcd != NULL, and is always set then */
+       char *string_buf = NULL;
+       char *debug_buf;
+       int known_size;
+       int needed = 85; /* seeded with average message length */
+       int max_nob;
+       va_list ap;
+       int retry;
+       int mask = msgdata->msg_mask;
+       char *file = (char *)msgdata->msg_file;
+       struct cfs_debug_limit_state *cdls = msgdata->msg_cdls;
+
+       if (strchr(file, '/'))
+               file = strrchr(file, '/') + 1;
+
+       tcd = cfs_trace_get_tcd();
+
+       /* cfs_trace_get_tcd() grabs a lock, which disables preemption and
+        * pins us to a particular CPU.  This avoids an smp_processor_id()
+        * warning on Linux when debugging is enabled.
+        */
+       cfs_set_ptldebug_header(&header, msgdata, CDEBUG_STACK());
 
-        depth = __current_nesting_level();
-        known_size = strlen(file) + 1 + depth;
-        if (msgdata->msg_fn)
-                known_size += strlen(msgdata->msg_fn) + 1;
-
-        if (libcfs_debug_binary)
-                known_size += sizeof(header);
-
-        /*/
-         * '2' used because vsnprintf return real size required for output
-         * _without_ terminating NULL.
-         * if needed is to small for this format.
-         */
-        for (i = 0; i < 2; i++) {
-                tage = cfs_trace_get_tage(tcd, needed + known_size + 1);
-                if (tage == NULL) {
-                       if (needed + known_size > PAGE_CACHE_SIZE)
-                                mask |= D_ERROR;
-
-                        cfs_trace_put_tcd(tcd);
-                        tcd = NULL;
-                        goto console;
-                }
+       if (!tcd)                /* arch may not log in IRQ context */
+               goto console;
+
+       if (tcd->tcd_cur_pages == 0)
+               header.ph_flags |= PH_FLAG_FIRST_RECORD;
+
+       if (tcd->tcd_shutting_down) {
+               cfs_trace_put_tcd(tcd);
+               tcd = NULL;
+               goto console;
+       }
+
+       known_size = strlen(file) + 1;
+       if (msgdata->msg_fn)
+               known_size += strlen(msgdata->msg_fn) + 1;
+
+       if (libcfs_debug_binary)
+               known_size += sizeof(header);
+
+       /*
+        * May perform an additional pass to update 'needed' and increase
+        * tage buffer size to match vsnprintf reported size required
+        * On the second pass (retry=1) use vscnprintf [which returns
+        * number of bytes written not including the terminating nul]
+        * to clarify `needed` is used as number of bytes written
+        * for the remainder of this function
+        */
+       for (retry = 0; retry < 2; retry++) {
+               tage = cfs_trace_get_tage(tcd, needed + known_size + 1);
+               if (!tage) {
+                       if (needed + known_size > PAGE_SIZE)
+                               mask |= D_ERROR;
+
+                       cfs_trace_put_tcd(tcd);
+                       tcd = NULL;
+                       goto console;
+               }
 
                string_buf = (char *)page_address(tage->page) +
-                                        tage->used + known_size;
+                            tage->used + known_size;
 
-               max_nob = PAGE_CACHE_SIZE - tage->used - known_size;
+               max_nob = PAGE_SIZE - tage->used - known_size;
                if (max_nob <= 0) {
-                       printk(KERN_EMERG "negative max_nob: %d\n",
-                              max_nob);
+                       pr_emerg("LustreError: negative max_nob: %d\n",
+                                max_nob);
                        mask |= D_ERROR;
                        cfs_trace_put_tcd(tcd);
                        tcd = NULL;
                        goto console;
                }
 
-                needed = 0;
-                if (format1) {
-                        va_copy(ap, args);
-                        needed = vsnprintf(string_buf, max_nob, format1, ap);
-                        va_end(ap);
-                }
-
-                if (format2) {
-                        remain = max_nob - needed;
-                        if (remain < 0)
-                                remain = 0;
-
-                        va_start(ap, format2);
-                        needed += vsnprintf(string_buf + needed, remain,
-                                            format2, ap);
-                        va_end(ap);
-                }
-
-                if (needed < max_nob) /* well. printing ok.. */
-                        break;
-        }
+               va_start(ap, format);
+               if (retry)
+                       needed = vscnprintf(string_buf, max_nob, format, ap);
+               else
+                       needed = vsnprintf(string_buf, max_nob, format, ap);
+               va_end(ap);
+
+               if (needed < max_nob) /* well. printing ok.. */
+                       break;
+       }
 
-       if (*(string_buf+needed-1) != '\n')
-               printk(KERN_INFO "format at %s:%d:%s doesn't end in "
-                      "newline\n", file, msgdata->msg_line, msgdata->msg_fn);
+       /* `needed` is actual bytes written to string_buf */
+       if (*(string_buf + needed - 1) != '\n') {
+               pr_info("Lustre: format at %s:%d:%s doesn't end in newline\n",
+                       file, msgdata->msg_line, msgdata->msg_fn);
+       }
 
-        header.ph_len = known_size + needed;
+       header.ph_len = known_size + needed;
        debug_buf = (char *)page_address(tage->page) + tage->used;
 
-        if (libcfs_debug_binary) {
-                memcpy(debug_buf, &header, sizeof(header));
-                tage->used += sizeof(header);
-                debug_buf += sizeof(header);
-        }
-
-        /* indent message according to the nesting level */
-        while (depth-- > 0) {
-                *(debug_buf++) = '.';
-                ++ tage->used;
-        }
+       if (libcfs_debug_binary) {
+               memcpy(debug_buf, &header, sizeof(header));
+               tage->used += sizeof(header);
+               debug_buf += sizeof(header);
+       }
 
-        strcpy(debug_buf, file);
-        tage->used += strlen(file) + 1;
-        debug_buf += strlen(file) + 1;
+       strlcpy(debug_buf, file, PAGE_SIZE - tage->used);
+       tage->used += strlen(file) + 1;
+       debug_buf += strlen(file) + 1;
 
-        if (msgdata->msg_fn) {
-                strcpy(debug_buf, msgdata->msg_fn);
-                tage->used += strlen(msgdata->msg_fn) + 1;
-                debug_buf += strlen(msgdata->msg_fn) + 1;
-        }
+       if (msgdata->msg_fn) {
+               strlcpy(debug_buf, msgdata->msg_fn, PAGE_SIZE - tage->used);
+               tage->used += strlen(msgdata->msg_fn) + 1;
+               debug_buf += strlen(msgdata->msg_fn) + 1;
+       }
 
-        __LASSERT(debug_buf == string_buf);
+       __LASSERT(debug_buf == string_buf);
 
-        tage->used += needed;
-       __LASSERT(tage->used <= PAGE_CACHE_SIZE);
+       tage->used += needed;
+       __LASSERT(tage->used <= PAGE_SIZE);
 
 console:
-        if ((mask & libcfs_printk) == 0) {
-                /* no console output requested */
-                if (tcd != NULL)
-                        cfs_trace_put_tcd(tcd);
-                return 1;
-        }
+       if ((mask & libcfs_printk) == 0) {
+               /* no console output requested */
+               if (tcd != NULL)
+                       cfs_trace_put_tcd(tcd);
+               return 1;
+       }
 
-        if (cdls != NULL) {
-                if (libcfs_console_ratelimit &&
-                    cdls->cdls_next != 0 &&     /* not first time ever */
-                    !cfs_time_after(cfs_time_current(), cdls->cdls_next)) {
-                        /* skipping a console message */
-                        cdls->cdls_count++;
-                        if (tcd != NULL)
-                                cfs_trace_put_tcd(tcd);
-                        return 1;
-                }
-
-                if (cfs_time_after(cfs_time_current(), cdls->cdls_next +
-                                                       libcfs_console_max_delay
-                                                       + cfs_time_seconds(10))) {
-                        /* last timeout was a long time ago */
-                        cdls->cdls_delay /= libcfs_console_backoff * 4;
-                } else {
-                        cdls->cdls_delay *= libcfs_console_backoff;
-                }
+       if (cdls != NULL) {
+               if (libcfs_console_ratelimit &&
+                   cdls->cdls_next != 0 &&     /* not first time ever */
+                   time_before(jiffies, cdls->cdls_next)) {
+                       /* skipping a console message */
+                       cdls->cdls_count++;
+                       if (tcd != NULL)
+                               cfs_trace_put_tcd(tcd);
+                       return 1;
+               }
+
+               if (time_after(jiffies, cdls->cdls_next +
+                                       libcfs_console_max_delay +
+                                       cfs_time_seconds(10))) {
+                       /* last timeout was a long time ago */
+                       cdls->cdls_delay /= libcfs_console_backoff * 4;
+               } else {
+                       cdls->cdls_delay *= libcfs_console_backoff;
+               }
 
                if (cdls->cdls_delay < libcfs_console_min_delay)
                        cdls->cdls_delay = libcfs_console_min_delay;
                else if (cdls->cdls_delay > libcfs_console_max_delay)
                        cdls->cdls_delay = libcfs_console_max_delay;
 
-                /* ensure cdls_next is never zero after it's been seen */
-                cdls->cdls_next = (cfs_time_current() + cdls->cdls_delay) | 1;
-        }
-
-        if (tcd != NULL) {
-                cfs_print_to_console(&header, mask, string_buf, needed, file,
-                                     msgdata->msg_fn);
-                cfs_trace_put_tcd(tcd);
-        } else {
-                string_buf = cfs_trace_get_console_buffer();
-
-                needed = 0;
-                if (format1 != NULL) {
-                        va_copy(ap, args);
-                        needed = vsnprintf(string_buf,
-                                           CFS_TRACE_CONSOLE_BUFFER_SIZE,
-                                           format1, ap);
-                        va_end(ap);
-                }
-                if (format2 != NULL) {
-                        remain = CFS_TRACE_CONSOLE_BUFFER_SIZE - needed;
-                        if (remain > 0) {
-                                va_start(ap, format2);
-                                needed += vsnprintf(string_buf+needed, remain,
-                                                    format2, ap);
-                                va_end(ap);
-                        }
-                }
-                cfs_print_to_console(&header, mask,
-                                     string_buf, needed, file, msgdata->msg_fn);
-
-                cfs_trace_put_console_buffer(string_buf);
-        }
-
-        if (cdls != NULL && cdls->cdls_count != 0) {
-                string_buf = cfs_trace_get_console_buffer();
+               /* ensure cdls_next is never zero after it's been seen */
+               cdls->cdls_next = (jiffies + cdls->cdls_delay) | 1;
+       }
 
-                needed = snprintf(string_buf, CFS_TRACE_CONSOLE_BUFFER_SIZE,
-                                  "Skipped %d previous similar message%s\n",
-                                  cdls->cdls_count,
-                                  (cdls->cdls_count > 1) ? "s" : "");
+       if (tcd) {
+               cfs_print_to_console(&header, mask, file, msgdata->msg_fn,
+                                    "%s", string_buf);
+               cfs_trace_put_tcd(tcd);
+       } else {
+               struct va_format vaf;
+
+               va_start(ap, format);
+               vaf.fmt = format;
+               vaf.va = &ap;
+               cfs_vprint_to_console(&header, mask,
+                                     &vaf, file, msgdata->msg_fn);
+               va_end(ap);
+       }
 
-                cfs_print_to_console(&header, mask,
-                                     string_buf, needed, file, msgdata->msg_fn);
+       if (cdls != NULL && cdls->cdls_count != 0) {
+               cfs_print_to_console(&header, mask, file,
+                                    msgdata->msg_fn,
+                                    "Skipped %d previous similar message%s\n",
+                                    cdls->cdls_count,
+                                    (cdls->cdls_count > 1) ? "s" : "");
 
-                cfs_trace_put_console_buffer(string_buf);
-                cdls->cdls_count = 0;
-        }
+               cdls->cdls_count = 0;
+       }
 
-        return 0;
+       return 0;
 }
-EXPORT_SYMBOL(libcfs_debug_vmsg2);
+EXPORT_SYMBOL(libcfs_debug_msg);
 
 void
 cfs_trace_assertion_failed(const char *str,
@@ -490,8 +575,8 @@ cfs_trace_assertion_failed(const char *str,
 
        cfs_set_ptldebug_header(&hdr, msgdata, CDEBUG_STACK());
 
-       cfs_print_to_console(&hdr, D_EMERG, str, strlen(str),
-                            msgdata->msg_file, msgdata->msg_fn);
+       cfs_print_to_console(&hdr, D_EMERG, msgdata->msg_file, msgdata->msg_fn,
+                            "%s", str);
 
        panic("Lustre debug assertion failure\n");
 
@@ -513,12 +598,6 @@ panic_collect_pages(struct page_collection *pc)
        cfs_tcd_for_each(tcd, i, j) {
                list_splice_init(&tcd->tcd_pages, &pc->pc_pages);
                tcd->tcd_cur_pages = 0;
-
-               if (pc->pc_want_daemon_pages) {
-                       list_splice_init(&tcd->tcd_daemon_pages,
-                                               &pc->pc_pages);
-                       tcd->tcd_cur_daemon_pages = 0;
-               }
        }
 }
 
@@ -527,15 +606,10 @@ static void collect_pages_on_all_cpus(struct page_collection *pc)
        struct cfs_trace_cpu_data *tcd;
        int i, cpu;
 
-       cfs_for_each_possible_cpu(cpu) {
+       for_each_possible_cpu(cpu) {
                cfs_tcd_for_each_type_lock(tcd, i, cpu) {
                        list_splice_init(&tcd->tcd_pages, &pc->pc_pages);
                        tcd->tcd_cur_pages = 0;
-                       if (pc->pc_want_daemon_pages) {
-                               list_splice_init(&tcd->tcd_daemon_pages,
-                                                       &pc->pc_pages);
-                               tcd->tcd_cur_daemon_pages = 0;
-                       }
                }
        }
 }
@@ -558,7 +632,7 @@ static void put_pages_back_on_all_cpus(struct page_collection *pc)
         struct cfs_trace_page *tmp;
         int i, cpu;
 
-        cfs_for_each_possible_cpu(cpu) {
+       for_each_possible_cpu(cpu) {
                 cfs_tcd_for_each_type_lock(tcd, i, cpu) {
                         cur_head = tcd->tcd_pages.next;
 
@@ -583,143 +657,139 @@ static void put_pages_back(struct page_collection *pc)
                 put_pages_back_on_all_cpus(pc);
 }
 
-/* Add pages to a per-cpu debug daemon ringbuffer.  This buffer makes sure that
- * we have a good amount of data at all times for dumping during an LBUG, even
- * if we have been steadily writing (and otherwise discarding) pages via the
- * debug daemon. */
-static void put_pages_on_tcd_daemon_list(struct page_collection *pc,
-                                        struct cfs_trace_cpu_data *tcd)
-{
-       struct cfs_trace_page *tage;
-       struct cfs_trace_page *tmp;
-
-       list_for_each_entry_safe(tage, tmp, &pc->pc_pages, linkage) {
-               __LASSERT_TAGE_INVARIANT(tage);
-
-               if (tage->cpu != tcd->tcd_cpu || tage->type != tcd->tcd_type)
-                       continue;
-
-               cfs_tage_to_tail(tage, &tcd->tcd_daemon_pages);
-               tcd->tcd_cur_daemon_pages++;
-
-               if (tcd->tcd_cur_daemon_pages > tcd->tcd_max_pages) {
-                       struct cfs_trace_page *victim;
-
-                       __LASSERT(!list_empty(&tcd->tcd_daemon_pages));
-                       victim = cfs_tage_from_list(tcd->tcd_daemon_pages.next);
-
-                        __LASSERT_TAGE_INVARIANT(victim);
-
-                       list_del(&victim->linkage);
-                       cfs_tage_free(victim);
-                       tcd->tcd_cur_daemon_pages--;
-               }
-       }
-}
-
-static void put_pages_on_daemon_list(struct page_collection *pc)
-{
-        struct cfs_trace_cpu_data *tcd;
-        int i, cpu;
-
-        cfs_for_each_possible_cpu(cpu) {
-                cfs_tcd_for_each_type_lock(tcd, i, cpu)
-                        put_pages_on_tcd_daemon_list(pc, tcd);
-        }
-}
-
+#ifdef LNET_DUMP_ON_PANIC
 void cfs_trace_debug_print(void)
 {
        struct page_collection pc;
        struct cfs_trace_page *tage;
        struct cfs_trace_page *tmp;
+       struct page *page;
 
-       pc.pc_want_daemon_pages = 1;
        collect_pages(&pc);
        list_for_each_entry_safe(tage, tmp, &pc.pc_pages, linkage) {
                char *p, *file, *fn;
-               struct page *page;
 
                __LASSERT_TAGE_INVARIANT(tage);
 
                page = tage->page;
                p = page_address(page);
                while (p < ((char *)page_address(page) + tage->used)) {
-                        struct ptldebug_header *hdr;
-                        int len;
-                        hdr = (void *)p;
-                        p += sizeof(*hdr);
-                        file = p;
-                        p += strlen(file) + 1;
-                        fn = p;
-                        p += strlen(fn) + 1;
-                        len = hdr->ph_len - (int)(p - (char *)hdr);
-
-                        cfs_print_to_console(hdr, D_EMERG, p, len, file, fn);
-
-                        p += len;
-                }
+                       struct ptldebug_header *hdr;
+                       int len;
+                       hdr = (void *)p;
+                       p += sizeof(*hdr);
+                       file = p;
+                       p += strlen(file) + 1;
+                       fn = p;
+                       p += strlen(fn) + 1;
+                       len = hdr->ph_len - (int)(p - (char *)hdr);
+
+                       cfs_print_to_console(hdr, D_EMERG, file, fn,
+                                            "%.*s", len, p);
+
+                       p += len;
+               }
 
                list_del(&tage->linkage);
                cfs_tage_free(tage);
        }
+       down_write(&cfs_tracefile_sem);
+       while ((page = list_first_entry_or_null(&daemon_pages,
+                                               struct page, lru)) != NULL) {
+               char *p, *file, *fn;
+
+               p = page_address(page);
+               while (p < ((char *)page_address(page) + page->private)) {
+                       struct ptldebug_header *hdr;
+                       int len;
+
+                       hdr = (void *)p;
+                       p += sizeof(*hdr);
+                       file = p;
+                       p += strlen(file) + 1;
+                       fn = p;
+                       p += strlen(fn) + 1;
+                       len = hdr->ph_len - (int)(p - (char *)hdr);
+
+                       cfs_print_to_console(hdr, D_EMERG, file, fn,
+                                            "%.*s", len, p);
+
+                       p += len;
+               }
+               list_del_init(&page->lru);
+               daemon_pages_count -= 1;
+               put_page(page);
+       }
+       up_write(&cfs_tracefile_sem);
 }
+#endif /* LNET_DUMP_ON_PANIC */
 
 int cfs_tracefile_dump_all_pages(char *filename)
 {
-       struct page_collection  pc;
-       struct file             *filp;
-       struct cfs_trace_page   *tage;
-       struct cfs_trace_page   *tmp;
+       struct page_collection pc;
+       struct file *filp;
+       struct cfs_trace_page *tage;
+       struct cfs_trace_page *tmp;
+       char *buf;
+       struct page *page;
        int rc;
 
-       DECL_MMSPACE;
-
-       cfs_tracefile_write_lock();
+       down_write(&cfs_tracefile_sem);
 
        filp = filp_open(filename, O_CREAT|O_EXCL|O_WRONLY|O_LARGEFILE, 0600);
        if (IS_ERR(filp)) {
                rc = PTR_ERR(filp);
                filp = NULL;
-               printk(KERN_ERR "LustreError: can't open %s for dump: rc %d\n",
-                     filename, rc);
+               pr_err("LustreError: can't open %s for dump: rc = %d\n",
+                      filename, rc);
                goto out;
        }
 
-        pc.pc_want_daemon_pages = 1;
-        collect_pages(&pc);
+       collect_pages(&pc);
        if (list_empty(&pc.pc_pages)) {
-                rc = 0;
-                goto close;
-        }
+               rc = 0;
+               goto close;
+       }
 
-        /* ok, for now, just write the pages.  in the future we'll be building
-         * iobufs with the pages and calling generic_direct_IO */
-       MMSPACE_OPEN;
+       /* ok, for now, just write the pages.  in the future we'll be building
+        * iobufs with the pages and calling generic_direct_IO */
        list_for_each_entry_safe(tage, tmp, &pc.pc_pages, linkage) {
 
-                __LASSERT_TAGE_INVARIANT(tage);
+               __LASSERT_TAGE_INVARIANT(tage);
 
-               rc = filp_write(filp, page_address(tage->page),
-                               tage->used, filp_poff(filp));
+               buf = kmap(tage->page);
+               rc = cfs_kernel_write(filp, buf, tage->used, &filp->f_pos);
+               kunmap(tage->page);
                if (rc != (int)tage->used) {
-                       printk(KERN_WARNING "wanted to write %u but wrote "
-                              "%d\n", tage->used, rc);
+                       pr_warn("Lustre: wanted to write %u but wrote %d\n",
+                               tage->used, rc);
                        put_pages_back(&pc);
                        __LASSERT(list_empty(&pc.pc_pages));
                        break;
                }
                list_del(&tage->linkage);
-                cfs_tage_free(tage);
-        }
-       MMSPACE_CLOSE;
-       rc = filp_fsync(filp, 0, LLONG_MAX);
+               cfs_tage_free(tage);
+       }
+       while ((page = list_first_entry_or_null(&daemon_pages,
+                                               struct page, lru)) != NULL) {
+               buf = page_address(page);
+               rc = cfs_kernel_write(filp, buf, page->private, &filp->f_pos);
+               if (rc != (int)page->private) {
+                       pr_warn("Lustre: wanted to write %u but wrote %d\n",
+                               (int)page->private, rc);
+                       break;
+               }
+               list_del(&page->lru);
+               daemon_pages_count -= 1;
+               put_page(page);
+       }
+       rc = vfs_fsync_range(filp, 0, LLONG_MAX, 1);
        if (rc)
-               printk(KERN_ERR "sync returns %d\n", rc);
+               pr_err("LustreError: sync returns: rc = %d\n", rc);
 close:
        filp_close(filp, NULL);
 out:
-       cfs_tracefile_write_unlock();
+       up_write(&cfs_tracefile_sem);
        return rc;
 }
 
@@ -727,48 +797,29 @@ void cfs_trace_flush_pages(void)
 {
        struct page_collection pc;
        struct cfs_trace_page *tage;
-       struct cfs_trace_page *tmp;
+       struct page *page;
 
-       pc.pc_want_daemon_pages = 1;
        collect_pages(&pc);
-       list_for_each_entry_safe(tage, tmp, &pc.pc_pages, linkage) {
-
+       while (!list_empty(&pc.pc_pages)) {
+               tage = list_first_entry(&pc.pc_pages,
+                                       struct cfs_trace_page, linkage);
                __LASSERT_TAGE_INVARIANT(tage);
 
                list_del(&tage->linkage);
                cfs_tage_free(tage);
        }
-}
-
-int cfs_trace_copyin_string(char *knl_buffer, int knl_buffer_nob,
-                            const char *usr_buffer, int usr_buffer_nob)
-{
-        int    nob;
-
-        if (usr_buffer_nob > knl_buffer_nob)
-                return -EOVERFLOW;
-
-       if (copy_from_user((void *)knl_buffer,
-                           (void *)usr_buffer, usr_buffer_nob))
-                return -EFAULT;
-
-        nob = strnlen(knl_buffer, usr_buffer_nob);
-        while (nob-- >= 0)                      /* strip trailing whitespace */
-                if (!isspace(knl_buffer[nob]))
-                        break;
 
-        if (nob < 0)                            /* empty string */
-                return -EINVAL;
-
-        if (nob == knl_buffer_nob)              /* no space to terminate */
-                return -EOVERFLOW;
-
-        knl_buffer[nob + 1] = 0;                /* terminate */
-        return 0;
+       down_write(&cfs_tracefile_sem);
+       while ((page = list_first_entry_or_null(&daemon_pages,
+                                               struct page, lru)) != NULL) {
+               list_del(&page->lru);
+               daemon_pages_count -= 1;
+               put_page(page);
+       }
+       up_write(&cfs_tracefile_sem);
 }
-EXPORT_SYMBOL(cfs_trace_copyin_string);
 
-int cfs_trace_copyout_string(char *usr_buffer, int usr_buffer_nob,
+int cfs_trace_copyout_string(char __user *usr_buffer, int usr_buffer_nob,
                              const char *knl_buffer, char *append)
 {
         /* NB if 'append' != NULL, it's a single character to append to the
@@ -793,66 +844,48 @@ int cfs_trace_copyout_string(char *usr_buffer, int usr_buffer_nob,
 }
 EXPORT_SYMBOL(cfs_trace_copyout_string);
 
-int cfs_trace_allocate_string_buffer(char **str, int nob)
+int cfs_trace_dump_debug_buffer_usrstr(void __user *usr_str, int usr_str_nob)
 {
-       if (nob > 2 * PAGE_CACHE_SIZE)  /* string must be "sensible" */
-                return -EINVAL;
-
-       *str = kmalloc(nob, GFP_IOFS | __GFP_ZERO);
-        if (*str == NULL)
-                return -ENOMEM;
+       char *str;
+       char *path;
+       int rc;
 
-        return 0;
-}
+       str = memdup_user_nul(usr_str, usr_str_nob);
+       if (IS_ERR(str))
+               return PTR_ERR(str);
 
-void cfs_trace_free_string_buffer(char *str, int nob)
-{
+       path = strim(str);
+       if (path[0] != '/')
+               rc = -EINVAL;
+       else
+               rc = cfs_tracefile_dump_all_pages(path);
        kfree(str);
-}
-
-int cfs_trace_dump_debug_buffer_usrstr(void *usr_str, int usr_str_nob)
-{
-        char         *str;
-        int           rc;
 
-        rc = cfs_trace_allocate_string_buffer(&str, usr_str_nob + 1);
-        if (rc != 0)
-                return rc;
-
-        rc = cfs_trace_copyin_string(str, usr_str_nob + 1,
-                                     usr_str, usr_str_nob);
-        if (rc != 0)
-                goto out;
-
-        if (str[0] != '/') {
-                rc = -EINVAL;
-                goto out;
-        }
-        rc = cfs_tracefile_dump_all_pages(str);
-out:
-        cfs_trace_free_string_buffer(str, usr_str_nob + 1);
-        return rc;
+       return rc;
 }
 
 int cfs_trace_daemon_command(char *str)
 {
         int       rc = 0;
 
-        cfs_tracefile_write_lock();
+       down_write(&cfs_tracefile_sem);
 
         if (strcmp(str, "stop") == 0) {
-                cfs_tracefile_write_unlock();
+               up_write(&cfs_tracefile_sem);
                 cfs_trace_stop_thread();
-                cfs_tracefile_write_lock();
+               down_write(&cfs_tracefile_sem);
                 memset(cfs_tracefile, 0, sizeof(cfs_tracefile));
 
-        } else if (strncmp(str, "size=", 5) == 0) {
-                cfs_tracefile_size = simple_strtoul(str + 5, NULL, 0);
-                if (cfs_tracefile_size < 10 || cfs_tracefile_size > 20480)
-                        cfs_tracefile_size = CFS_TRACEFILE_SIZE;
-                else
-                        cfs_tracefile_size <<= 20;
+       } else if (strncmp(str, "size=", 5) == 0) {
+               unsigned long tmp;
 
+               rc = kstrtoul(str + 5, 10, &tmp);
+               if (!rc) {
+                       if (tmp < 10 || tmp > 20480)
+                               cfs_tracefile_size = CFS_TRACEFILE_SIZE;
+                       else
+                               cfs_tracefile_size = tmp << 20;
+               }
         } else if (strlen(str) >= sizeof(cfs_tracefile)) {
                 rc = -ENAMETOOLONG;
         } else if (str[0] != '/') {
@@ -860,81 +893,64 @@ int cfs_trace_daemon_command(char *str)
         } else {
                strcpy(cfs_tracefile, str);
 
-               printk(KERN_INFO
-                      "Lustre: debug daemon will attempt to start writing "
-                      "to %s (%lukB max)\n", cfs_tracefile,
-                      (long)(cfs_tracefile_size >> 10));
+               pr_info("Lustre: debug daemon will attempt to start writing to %s (%lukB max)\n",
+                       cfs_tracefile, (long)(cfs_tracefile_size >> 10));
 
                cfs_trace_start_thread();
         }
 
-        cfs_tracefile_write_unlock();
+       up_write(&cfs_tracefile_sem);
         return rc;
 }
 
-int cfs_trace_daemon_command_usrstr(void *usr_str, int usr_str_nob)
+int cfs_trace_daemon_command_usrstr(void __user *usr_str, int usr_str_nob)
 {
-        char *str;
-        int   rc;
+       char *str;
+       int   rc;
 
-        rc = cfs_trace_allocate_string_buffer(&str, usr_str_nob + 1);
-        if (rc != 0)
-                return rc;
+       str = memdup_user_nul(usr_str, usr_str_nob);
+       if (IS_ERR(str))
+               return PTR_ERR(str);
 
-        rc = cfs_trace_copyin_string(str, usr_str_nob + 1,
-                                 usr_str, usr_str_nob);
-        if (rc == 0)
-                rc = cfs_trace_daemon_command(str);
+       rc = cfs_trace_daemon_command(strim(str));
+       kfree(str);
 
-        cfs_trace_free_string_buffer(str, usr_str_nob + 1);
-        return rc;
+       return rc;
 }
 
 int cfs_trace_set_debug_mb(int mb)
 {
        int i;
        int j;
-       int pages;
-       int limit = cfs_trace_max_debug_mb();
+       unsigned long pages;
+       unsigned long total_mb = (cfs_totalram_pages() >> (20 - PAGE_SHIFT));
+       unsigned long limit = max_t(unsigned long, 512, (total_mb * 4) / 5);
        struct cfs_trace_cpu_data *tcd;
 
        if (mb < num_possible_cpus()) {
-               printk(KERN_WARNING
-                      "Lustre: %d MB is too small for debug buffer size, "
-                      "setting it to %d MB.\n", mb, num_possible_cpus());
+               pr_warn("Lustre: %d MB is too small for debug buffer size, setting it to %d MB.\n",
+                       mb, num_possible_cpus());
                mb = num_possible_cpus();
        }
 
        if (mb > limit) {
-               printk(KERN_WARNING
-                      "Lustre: %d MB is too large for debug buffer size, "
-                      "setting it to %d MB.\n", mb, limit);
+               pr_warn("Lustre: %d MB is too large for debug buffer size, setting it to %lu MB.\n",
+                       mb, limit);
                mb = limit;
        }
 
        mb /= num_possible_cpus();
-       pages = mb << (20 - PAGE_CACHE_SHIFT);
+       pages = mb << (20 - PAGE_SHIFT);
 
-       cfs_tracefile_write_lock();
+       down_write(&cfs_tracefile_sem);
 
        cfs_tcd_for_each(tcd, i, j)
                tcd->tcd_max_pages = (pages * tcd->tcd_pages_factor) / 100;
 
-       cfs_tracefile_write_unlock();
+       daemon_pages_max = pages;
+       up_write(&cfs_tracefile_sem);
 
-       return 0;
-}
-
-int cfs_trace_set_debug_mb_usrstr(void *usr_str, int usr_str_nob)
-{
-        char     str[32];
-        int      rc;
-
-        rc = cfs_trace_copyin_string(str, sizeof(str), usr_str, usr_str_nob);
-        if (rc < 0)
-                return rc;
-
-        return cfs_trace_set_debug_mb(simple_strtoul(str, NULL, 0));
+       return mb;
 }
 
 int cfs_trace_get_debug_mb(void)
@@ -944,211 +960,226 @@ int cfs_trace_get_debug_mb(void)
         struct cfs_trace_cpu_data *tcd;
         int total_pages = 0;
 
-        cfs_tracefile_read_lock();
+       down_read(&cfs_tracefile_sem);
 
         cfs_tcd_for_each(tcd, i, j)
                 total_pages += tcd->tcd_max_pages;
 
-        cfs_tracefile_read_unlock();
+       up_read(&cfs_tracefile_sem);
 
-       return (total_pages >> (20 - PAGE_CACHE_SHIFT)) + 1;
+       return (total_pages >> (20 - PAGE_SHIFT)) + 1;
 }
 
 static int tracefiled(void *arg)
 {
        struct page_collection pc;
-       struct tracefiled_ctl *tctl = arg;
        struct cfs_trace_page *tage;
        struct cfs_trace_page *tmp;
        struct file *filp;
+       char *buf;
        int last_loop = 0;
        int rc;
 
-       DECL_MMSPACE;
-
-       /* we're started late enough that we pick up init's fs context */
-       /* this is so broken in uml?  what on earth is going on? */
-
-       complete(&tctl->tctl_start);
-
-       while (1) {
-               wait_queue_t __wait;
-
-                pc.pc_want_daemon_pages = 0;
-                collect_pages(&pc);
+       while (!last_loop) {
+               LIST_HEAD(for_daemon_pages);
+               int for_daemon_pages_count = 0;
+               schedule_timeout_interruptible(cfs_time_seconds(1));
+               if (kthread_should_stop())
+                       last_loop = 1;
+               collect_pages(&pc);
                if (list_empty(&pc.pc_pages))
-                        goto end_loop;
+                       continue;
 
-                filp = NULL;
-                cfs_tracefile_read_lock();
-                if (cfs_tracefile[0] != 0) {
+               filp = NULL;
+               down_read(&cfs_tracefile_sem);
+               if (cfs_tracefile[0] != 0) {
                        filp = filp_open(cfs_tracefile,
                                         O_CREAT | O_RDWR | O_LARGEFILE,
                                         0600);
                        if (IS_ERR(filp)) {
                                rc = PTR_ERR(filp);
                                filp = NULL;
-                               printk(KERN_WARNING "couldn't open %s: "
-                                      "%d\n", cfs_tracefile, rc);
+                               pr_warn("Lustre: couldn't open %s: rc = %d\n",
+                                       cfs_tracefile, rc);
                        }
                }
-                cfs_tracefile_read_unlock();
-                if (filp == NULL) {
-                        put_pages_on_daemon_list(&pc);
-                       __LASSERT(list_empty(&pc.pc_pages));
-                        goto end_loop;
-                }
-
-               MMSPACE_OPEN;
+               up_read(&cfs_tracefile_sem);
 
                list_for_each_entry_safe(tage, tmp, &pc.pc_pages, linkage) {
-                        static loff_t f_pos;
-
-                        __LASSERT_TAGE_INVARIANT(tage);
-
-                        if (f_pos >= (off_t)cfs_tracefile_size)
-                                f_pos = 0;
-                       else if (f_pos > (off_t)filp_size(filp))
-                               f_pos = filp_size(filp);
-
-                       rc = filp_write(filp, page_address(tage->page),
-                                       tage->used, &f_pos);
-                       if (rc != (int)tage->used) {
-                               printk(KERN_WARNING "wanted to write %u "
-                                      "but wrote %d\n", tage->used, rc);
-                               put_pages_back(&pc);
-                               __LASSERT(list_empty(&pc.pc_pages));
-                               break;
+                       __LASSERT_TAGE_INVARIANT(tage);
+
+                       if (filp) {
+                               struct dentry *de = file_dentry(filp);
+                               static loff_t f_pos;
+
+                               if (f_pos >= (off_t)cfs_tracefile_size)
+                                       f_pos = 0;
+                               else if (f_pos > i_size_read(de->d_inode))
+                                       f_pos = i_size_read(de->d_inode);
+
+                               buf = kmap(tage->page);
+                               rc = cfs_kernel_write(filp, buf, tage->used,
+                                                     &f_pos);
+                               kunmap(tage->page);
+                               if (rc != (int)tage->used) {
+                                       pr_warn("Lustre: wanted to write %u but wrote %d\n",
+                                               tage->used, rc);
+                                       put_pages_back(&pc);
+                                       __LASSERT(list_empty(&pc.pc_pages));
+                                       break;
+                               }
                        }
-                }
-               MMSPACE_CLOSE;
+                       list_del_init(&tage->linkage);
+                       list_add_tail(&tage->page->lru, &for_daemon_pages);
+                       for_daemon_pages_count += 1;
+
+                       tage->page->private = (int)tage->used;
+                       kfree(tage);
+                       atomic_dec(&cfs_tage_allocated);
+               }
+
+               if (filp)
+                       filp_close(filp, NULL);
+
+               down_write(&cfs_tracefile_sem);
+               list_splice_tail(&for_daemon_pages, &daemon_pages);
+               daemon_pages_count += for_daemon_pages_count;
+               while (daemon_pages_count > daemon_pages_max) {
+                       struct page *p = list_first_entry(&daemon_pages,
+                                                         struct page, lru);
+                       list_del(&p->lru);
+                       put_page(p);
+                       daemon_pages_count -= 1;
+               }
+               up_write(&cfs_tracefile_sem);
 
-               filp_close(filp, NULL);
-                put_pages_on_daemon_list(&pc);
                if (!list_empty(&pc.pc_pages)) {
-                        int i;
+                       int i;
 
-                       printk(KERN_ALERT "Lustre: trace pages aren't "
-                              " empty\n");
-                       printk(KERN_ERR "total cpus(%d): ",
-                              num_possible_cpus());
+                       pr_alert("Lustre: trace pages aren't empty\n");
+                       pr_err("Lustre: total cpus(%d): ", num_possible_cpus());
                        for (i = 0; i < num_possible_cpus(); i++)
                                if (cpu_online(i))
-                                       printk(KERN_ERR "%d(on) ", i);
+                                       pr_cont("%d(on) ", i);
                                else
-                                       printk(KERN_ERR "%d(off) ", i);
-                       printk(KERN_ERR "\n");
+                                       pr_cont("%d(off) ", i);
+                       pr_cont("\n");
 
                        i = 0;
                        list_for_each_entry_safe(tage, tmp, &pc.pc_pages,
-                                                    linkage)
-                               printk(KERN_ERR "page %d belongs to cpu "
-                                      "%d\n", ++i, tage->cpu);
-                       printk(KERN_ERR "There are %d pages unwritten\n",
-                              i);
+                                                linkage)
+                               pr_err("Lustre: page %d belongs to cpu %d\n",
+                                      ++i, tage->cpu);
+                       pr_err("Lustre: There are %d pages unwritten\n", i);
                }
                __LASSERT(list_empty(&pc.pc_pages));
-end_loop:
-               if (atomic_read(&tctl->tctl_shutdown)) {
-                       if (last_loop == 0) {
-                               last_loop = 1;
-                               continue;
-                       } else {
-                               break;
-                       }
-               }
-               init_waitqueue_entry_current(&__wait);
-               add_wait_queue(&tctl->tctl_waitq, &__wait);
-               set_current_state(TASK_INTERRUPTIBLE);
-               waitq_timedwait(&__wait, TASK_INTERRUPTIBLE,
-                               cfs_time_seconds(1));
-               remove_wait_queue(&tctl->tctl_waitq, &__wait);
-        }
-       complete(&tctl->tctl_stop);
-        return 0;
+       }
+
+       return 0;
 }
 
 int cfs_trace_start_thread(void)
 {
-        struct tracefiled_ctl *tctl = &trace_tctl;
-        int rc = 0;
+       struct task_struct *tsk;
+       int rc = 0;
 
-       mutex_lock(&cfs_trace_thread_mutex);
-        if (thread_running)
-                goto out;
+       if (tctl_task)
+               return 0;
 
-       init_completion(&tctl->tctl_start);
-       init_completion(&tctl->tctl_stop);
-       init_waitqueue_head(&tctl->tctl_waitq);
-       atomic_set(&tctl->tctl_shutdown, 0);
-
-       if (IS_ERR(kthread_run(tracefiled, tctl, "ktracefiled"))) {
+       tsk = kthread_create(tracefiled, NULL, "ktracefiled");
+       if (IS_ERR(tsk))
                rc = -ECHILD;
-               goto out;
-       }
+       else if (cmpxchg(&tctl_task, NULL, tsk) != NULL)
+               /* already running */
+               kthread_stop(tsk);
+       else
+               wake_up_process(tsk);
 
-       wait_for_completion(&tctl->tctl_start);
-       thread_running = 1;
-out:
-       mutex_unlock(&cfs_trace_thread_mutex);
-        return rc;
+       return rc;
 }
 
 void cfs_trace_stop_thread(void)
 {
-       struct tracefiled_ctl *tctl = &trace_tctl;
-
-       mutex_lock(&cfs_trace_thread_mutex);
-       if (thread_running) {
-               printk(KERN_INFO
-                      "Lustre: shutting down debug daemon thread...\n");
-               atomic_set(&tctl->tctl_shutdown, 1);
-               wait_for_completion(&tctl->tctl_stop);
-               thread_running = 0;
+       struct task_struct *tsk;
+
+       tsk = xchg(&tctl_task, NULL);
+       if (tsk) {
+               pr_info("Lustre: shutting down debug daemon thread...\n");
+               kthread_stop(tsk);
        }
-       mutex_unlock(&cfs_trace_thread_mutex);
 }
 
+/* percents to share the total debug memory for each type */
+static unsigned int pages_factor[CFS_TCD_TYPE_CNT] = {
+       80, /* 80% pages for CFS_TCD_TYPE_PROC */
+       10, /* 10% pages for CFS_TCD_TYPE_SOFTIRQ */
+       10  /* 10% pages for CFS_TCD_TYPE_IRQ */
+};
+
 int cfs_tracefile_init(int max_pages)
 {
        struct cfs_trace_cpu_data *tcd;
-       int     i;
-       int     j;
-       int     rc;
-       int     factor;
+       int i;
+       int j;
 
-       rc = cfs_tracefile_init_arch();
-       if (rc != 0)
-               return rc;
+       /* initialize trace_data */
+       memset(cfs_trace_data, 0, sizeof(cfs_trace_data));
+       for (i = 0; i < CFS_TCD_TYPE_CNT; i++) {
+               cfs_trace_data[i] =
+                       kmalloc_array(num_possible_cpus(),
+                                     sizeof(union cfs_trace_data_union),
+                                     GFP_KERNEL);
+               if (!cfs_trace_data[i])
+                       goto out_trace_data;
+       }
 
+       /* arch related info initialized */
        cfs_tcd_for_each(tcd, i, j) {
-               /* tcd_pages_factor is initialized int tracefile_init_arch. */
-               factor = tcd->tcd_pages_factor;
+               int factor = pages_factor[i];
+
+               spin_lock_init(&tcd->tcd_lock);
+               tcd->tcd_pages_factor = factor;
+               tcd->tcd_type = i;
+               tcd->tcd_cpu = j;
+
                INIT_LIST_HEAD(&tcd->tcd_pages);
                INIT_LIST_HEAD(&tcd->tcd_stock_pages);
-               INIT_LIST_HEAD(&tcd->tcd_daemon_pages);
                tcd->tcd_cur_pages = 0;
                tcd->tcd_cur_stock_pages = 0;
-               tcd->tcd_cur_daemon_pages = 0;
                tcd->tcd_max_pages = (max_pages * factor) / 100;
                LASSERT(tcd->tcd_max_pages > 0);
                tcd->tcd_shutting_down = 0;
        }
+       daemon_pages_max = max_pages;
+
        return 0;
+
+out_trace_data:
+       for (i = 0; cfs_trace_data[i]; i++) {
+               kfree(cfs_trace_data[i]);
+               cfs_trace_data[i] = NULL;
+       }
+       pr_err("lnet: Not enough memory\n");
+       return -ENOMEM;
 }
 
 static void trace_cleanup_on_all_cpus(void)
 {
        struct cfs_trace_cpu_data *tcd;
        struct cfs_trace_page *tage;
-       struct cfs_trace_page *tmp;
        int i, cpu;
 
-       cfs_for_each_possible_cpu(cpu) {
+       for_each_possible_cpu(cpu) {
                cfs_tcd_for_each_type_lock(tcd, i, cpu) {
+                       if (!tcd->tcd_pages_factor)
+                               /* Not initialised */
+                               continue;
                        tcd->tcd_shutting_down = 1;
 
-                       list_for_each_entry_safe(tage, tmp, &tcd->tcd_pages, linkage) {
+                       while (!list_empty(&tcd->tcd_pages)) {
+                               tage = list_first_entry(&tcd->tcd_pages,
+                                                       struct cfs_trace_page,
+                                                       linkage);
                                __LASSERT_TAGE_INVARIANT(tage);
 
                                list_del(&tage->linkage);
@@ -1162,16 +1193,21 @@ static void trace_cleanup_on_all_cpus(void)
 static void cfs_trace_cleanup(void)
 {
        struct page_collection pc;
+       int i;
 
        INIT_LIST_HEAD(&pc.pc_pages);
 
        trace_cleanup_on_all_cpus();
 
-       cfs_tracefile_fini_arch();
+       for (i = 0; i < CFS_TCD_TYPE_CNT && cfs_trace_data[i]; i++) {
+               kfree(cfs_trace_data[i]);
+               cfs_trace_data[i] = NULL;
+       }
 }
 
 void cfs_tracefile_exit(void)
 {
-        cfs_trace_stop_thread();
-        cfs_trace_cleanup();
+       cfs_trace_stop_thread();
+       cfs_trace_flush_pages();
+       cfs_trace_cleanup();
 }