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27 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
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36 * Author: Eric Barton <eeb@clusterfs.com>
39 #define DEBUG_SUBSYSTEM S_LNET
41 #include <libcfs/libcfs.h>
47 lwt_cpu_t lwt_cpus[CFS_NR_CPUS];
50 int lwt_pages_per_cpu;
52 /* NB only root is allowed to retrieve LWT info; it's an open door into the
56 lwt_lookup_string (int *size, char *knl_ptr,
57 char *user_ptr, int user_size)
61 /* knl_ptr was retrieved from an LWT snapshot and the caller wants to
62 * turn it into a string. NB we can crash with an access violation
63 * trying to determine the string length, so we're trusting our
66 if (!cfs_capable(CFS_CAP_SYS_ADMIN))
73 *size = strnlen (knl_ptr, maxsize - 1) + 1;
75 if (user_ptr != NULL) {
79 if (cfs_copy_to_user (user_ptr, knl_ptr, *size))
82 /* Did I truncate the string? */
83 if (knl_ptr[*size - 1] != 0)
84 cfs_copy_to_user (user_ptr + *size - 4, "...", 4);
91 lwt_control (int enable, int clear)
97 if (!cfs_capable(CFS_CAP_SYS_ADMIN))
104 /* give people some time to stop adding traces */
105 cfs_schedule_timeout(10);
108 for (i = 0; i < cfs_num_online_cpus(); i++) {
109 p = lwt_cpus[i].lwtc_current_page;
117 for (j = 0; j < lwt_pages_per_cpu; j++) {
118 memset (p->lwtp_events, 0, CFS_PAGE_SIZE);
120 p = cfs_list_entry (p->lwtp_list.next,
121 lwt_page_t, lwtp_list);
135 lwt_snapshot (cfs_cycles_t *now, int *ncpu, int *total_size,
136 void *user_ptr, int user_size)
138 const int events_per_page = CFS_PAGE_SIZE / sizeof(lwt_event_t);
139 const int bytes_per_page = events_per_page * sizeof(lwt_event_t);
144 if (!cfs_capable(CFS_CAP_SYS_ADMIN))
147 *ncpu = cfs_num_online_cpus();
148 *total_size = cfs_num_online_cpus() * lwt_pages_per_cpu *
152 if (user_ptr == NULL)
155 for (i = 0; i < cfs_num_online_cpus(); i++) {
156 p = lwt_cpus[i].lwtc_current_page;
161 for (j = 0; j < lwt_pages_per_cpu; j++) {
162 if (cfs_copy_to_user(user_ptr, p->lwtp_events,
166 user_ptr = ((char *)user_ptr) + bytes_per_page;
167 p = cfs_list_entry(p->lwtp_list.next,
168 lwt_page_t, lwtp_list);
181 for (i = 0; i < cfs_num_online_cpus(); i++)
182 if (lwt_cpus[i].lwtc_current_page != NULL)
185 LASSERT (!lwt_enabled);
187 /* NULL pointers, zero scalars */
188 memset (lwt_cpus, 0, sizeof (lwt_cpus));
190 LWT_MEMORY / (cfs_num_online_cpus() * CFS_PAGE_SIZE);
192 for (i = 0; i < cfs_num_online_cpus(); i++)
193 for (j = 0; j < lwt_pages_per_cpu; j++) {
194 struct page *page = alloc_page (GFP_KERNEL);
198 CERROR ("Can't allocate page\n");
203 LIBCFS_ALLOC(lwtp, sizeof (*lwtp));
205 CERROR ("Can't allocate lwtp\n");
211 lwtp->lwtp_page = page;
212 lwtp->lwtp_events = page_address(page);
213 memset (lwtp->lwtp_events, 0, CFS_PAGE_SIZE);
216 CFS_INIT_LIST_HEAD (&lwtp->lwtp_list);
217 lwt_cpus[i].lwtc_current_page = lwtp;
219 cfs_list_add (&lwtp->lwtp_list,
220 &lwt_cpus[i].lwtc_current_page->lwtp_list);
239 for (i = 0; i < cfs_num_online_cpus(); i++)
240 while (lwt_cpus[i].lwtc_current_page != NULL) {
241 lwt_page_t *lwtp = lwt_cpus[i].lwtc_current_page;
243 if (cfs_list_empty (&lwtp->lwtp_list)) {
244 lwt_cpus[i].lwtc_current_page = NULL;
246 lwt_cpus[i].lwtc_current_page =
247 cfs_list_entry (lwtp->lwtp_list.next,
248 lwt_page_t, lwtp_list);
250 cfs_list_del (&lwtp->lwtp_list);
253 __free_page (lwtp->lwtp_page);
254 LIBCFS_FREE (lwtp, sizeof (*lwtp));
258 EXPORT_SYMBOL(lwt_enabled);
259 EXPORT_SYMBOL(lwt_cpus);
261 EXPORT_SYMBOL(lwt_init);
262 EXPORT_SYMBOL(lwt_fini);
263 EXPORT_SYMBOL(lwt_lookup_string);
264 EXPORT_SYMBOL(lwt_control);
265 EXPORT_SYMBOL(lwt_snapshot);