X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-context-vtid.c;h=36e5695daf89143e1b28f01f600759d5adda5ab0;hb=HEAD;hp=80661f632d8c0305ad059706e8d6528668420a0c;hpb=70b36cd63f75c305d948bbce2177d834df5d8323;p=lttng-ust.git diff --git a/liblttng-ust/lttng-context-vtid.c b/liblttng-ust/lttng-context-vtid.c deleted file mode 100644 index 80661f63..00000000 --- a/liblttng-ust/lttng-context-vtid.c +++ /dev/null @@ -1,122 +0,0 @@ -/* - * lttng-context-vtid.c - * - * LTTng UST vtid context. - * - * Copyright (C) 2009-2012 Mathieu Desnoyers - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; only - * version 2.1 of the License. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - */ - -#define _LGPL_SOURCE -#include -#include -#include -#include -#include -#include -#include -#include "lttng-tracer-core.h" - -/* - * We cache the result to ensure we don't trigger a system call for - * each event. - */ -static DEFINE_URCU_TLS(pid_t, cached_vtid); - -/* - * Upon fork or clone, the TID assigned to our thread is not the same as - * we kept in cache. Luckily, we are the only thread surviving in the - * child process, so we can simply clear our cached version. - */ -void lttng_context_vtid_reset(void) -{ - CMM_STORE_SHARED(URCU_TLS(cached_vtid), 0); -} - -static -size_t vtid_get_size(struct lttng_ctx_field *field, size_t offset) -{ - size_t size = 0; - - size += lib_ring_buffer_align(offset, lttng_alignof(pid_t)); - size += sizeof(pid_t); - return size; -} - -static inline -pid_t wrapper_getvtid(void) -{ - pid_t vtid; - - vtid = CMM_LOAD_SHARED(URCU_TLS(cached_vtid)); - if (caa_unlikely(!vtid)) { - vtid = gettid(); - CMM_STORE_SHARED(URCU_TLS(cached_vtid), vtid); - } - return vtid; -} - -static -void vtid_record(struct lttng_ctx_field *field, - struct lttng_ust_lib_ring_buffer_ctx *ctx, - struct lttng_channel *chan) -{ - pid_t vtid = wrapper_getvtid(); - - lib_ring_buffer_align_ctx(ctx, lttng_alignof(vtid)); - chan->ops->event_write(ctx, &vtid, sizeof(vtid)); -} - -static -void vtid_get_value(struct lttng_ctx_field *field, - struct lttng_ctx_value *value) -{ - value->u.s64 = wrapper_getvtid(); -} - -int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx) -{ - struct lttng_ctx_field *field; - - field = lttng_append_context(ctx); - if (!field) - return -ENOMEM; - if (lttng_find_context(*ctx, "vtid")) { - lttng_remove_context_field(ctx, field); - return -EEXIST; - } - field->event_field.name = "vtid"; - field->event_field.type.atype = atype_integer; - field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT; - field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT; - field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t); - field->event_field.type.u.basic.integer.reverse_byte_order = 0; - field->event_field.type.u.basic.integer.base = 10; - field->event_field.type.u.basic.integer.encoding = lttng_encode_none; - field->get_size = vtid_get_size; - field->record = vtid_record; - field->get_value = vtid_get_value; - lttng_context_update(*ctx); - return 0; -} - -/* - * Force a read (imply TLS fixup for dlopen) of TLS variables. - */ -void lttng_fixup_vtid_tls(void) -{ - asm volatile ("" : : "m" (URCU_TLS(cached_vtid))); -}