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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[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 (copy_to_user(user_ptr, knl_ptr, *size))
82 /* Did I truncate the string? */
83 if (knl_ptr[*size - 1] != 0)
84 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 schedule_timeout(10);
108 for (i = 0; i < 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, PAGE_CACHE_SIZE);
120 p = 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 = PAGE_CACHE_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 = num_online_cpus();
148 *total_size = num_online_cpus() * lwt_pages_per_cpu * bytes_per_page;
151 if (user_ptr == NULL)
154 for (i = 0; i < num_online_cpus(); i++) {
155 p = lwt_cpus[i].lwtc_current_page;
160 for (j = 0; j < lwt_pages_per_cpu; j++) {
161 if (copy_to_user(user_ptr, p->lwtp_events,
165 user_ptr = ((char *)user_ptr) + bytes_per_page;
166 p = list_entry(p->lwtp_list.next,
167 lwt_page_t, lwtp_list);
178 for (i = 0; i < num_online_cpus(); i++)
179 if (lwt_cpus[i].lwtc_current_page != NULL)
182 LASSERT (!lwt_enabled);
184 /* NULL pointers, zero scalars */
185 memset (lwt_cpus, 0, sizeof (lwt_cpus));
186 lwt_pages_per_cpu = LWT_MEMORY / (num_online_cpus() * PAGE_CACHE_SIZE);
188 for (i = 0; i < num_online_cpus(); i++)
189 for (j = 0; j < lwt_pages_per_cpu; j++) {
190 struct page *page = alloc_page(GFP_KERNEL);
194 CERROR ("Can't allocate page\n");
199 LIBCFS_ALLOC(lwtp, sizeof (*lwtp));
201 CERROR ("Can't allocate lwtp\n");
207 lwtp->lwtp_page = page;
208 lwtp->lwtp_events = page_address(page);
209 memset(lwtp->lwtp_events, 0, PAGE_CACHE_SIZE);
212 INIT_LIST_HEAD (&lwtp->lwtp_list);
213 lwt_cpus[i].lwtc_current_page = lwtp;
215 list_add(&lwtp->lwtp_list,
216 &lwt_cpus[i].lwtc_current_page->lwtp_list);
234 for (i = 0; i < num_online_cpus(); i++)
235 while (lwt_cpus[i].lwtc_current_page != NULL) {
236 lwt_page_t *lwtp = lwt_cpus[i].lwtc_current_page;
238 if (list_empty (&lwtp->lwtp_list)) {
239 lwt_cpus[i].lwtc_current_page = NULL;
241 lwt_cpus[i].lwtc_current_page =
242 list_entry(lwtp->lwtp_list.next,
243 lwt_page_t, lwtp_list);
244 list_del (&lwtp->lwtp_list);
246 __free_page (lwtp->lwtp_page);
247 LIBCFS_FREE (lwtp, sizeof (*lwtp));
251 EXPORT_SYMBOL(lwt_enabled);
252 EXPORT_SYMBOL(lwt_cpus);
254 EXPORT_SYMBOL(lwt_init);
255 EXPORT_SYMBOL(lwt_fini);
256 EXPORT_SYMBOL(lwt_lookup_string);
257 EXPORT_SYMBOL(lwt_control);
258 EXPORT_SYMBOL(lwt_snapshot);