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ruby--ruby/ccan/container_of/container_of.h
normal f11db2a605 vm*: doubly-linked list from ccan to manage vm->living_threads
A doubly-linked list for tracking living threads guarantees
constant-time insert/delete performance with no corner cases of a
hash table.  I chose this ccan implementation of doubly-linked
lists over the BSD sys/queue.h implementation since:

1) insertion and removal are both branchless
2) locality is improved if a struct may be a member of multiple lists
   (0002 patch in Feature 9632 will introduce a secondary list
   for waiting FDs)

This also increases cache locality during iteration: improving
performance in a new IO#close benchmark with many sleeping threads
while still scanning the same number of threads.

	vm_thread_close 1.762

* vm_core.h (rb_vm_t): list_head and counter for living_threads
  (rb_thread_t): vmlt_node for living_threads linkage
  (rb_vm_living_threads_init): new function wrapper
  (rb_vm_living_threads_insert): ditto
  (rb_vm_living_threads_remove): ditto
* vm.c (rb_vm_living_threads_foreach): new function wrapper
* thread.c (terminate_i, thread_start_func_2, thread_create_core,
  thread_fd_close_i, thread_fd_close): update to use new APIs
* vm.c (vm_mark_each_thread_func, rb_vm_mark, ruby_vm_destruct,
  vm_memsize, vm_init2, Init_VM): ditto
* vm_trace.c (clear_trace_func_i, rb_clear_trace_func): ditto
* benchmark/bm_vm_thread_close.rb: added to show improvement
* ccan/build_assert/build_assert.h: added as a dependency of list.h
* ccan/check_type/check_type.h: ditto
* ccan/container_of/container_of.h: ditto
* ccan/licenses/BSD-MIT: ditto
* ccan/licenses/CC0: ditto
* ccan/str/str.h: ditto (stripped of unused macros)
* ccan/list/list.h: ditto
* common.mk: add CCAN_LIST_INCLUDES
  [ruby-core:61871][Feature 9632 (part 1)]

Apologies for the size of this commit, but I think a good
doubly-linked list will be useful for future features, too.
This may be used to add ordering to a container_of-based hash
table to preserve compatibility if required (e.g. feature 9614).

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45913 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
2014-05-10 23:48:51 +00:00

106 lines
3 KiB
C

/* CC0 (Public domain) - see ccan/licenses/CC0 file for details */
#ifndef CCAN_CONTAINER_OF_H
#define CCAN_CONTAINER_OF_H
#include "ccan/check_type/check_type.h"
/**
* container_of - get pointer to enclosing structure
* @member_ptr: pointer to the structure member
* @containing_type: the type this member is within
* @member: the name of this member within the structure.
*
* Given a pointer to a member of a structure, this macro does pointer
* subtraction to return the pointer to the enclosing type.
*
* Example:
* struct foo {
* int fielda, fieldb;
* // ...
* };
* struct info {
* int some_other_field;
* struct foo my_foo;
* };
*
* static struct info *foo_to_info(struct foo *foo)
* {
* return container_of(foo, struct info, my_foo);
* }
*/
#define container_of(member_ptr, containing_type, member) \
((containing_type *) \
((char *)(member_ptr) \
- container_off(containing_type, member)) \
+ check_types_match(*(member_ptr), ((containing_type *)0)->member))
/**
* container_off - get offset to enclosing structure
* @containing_type: the type this member is within
* @member: the name of this member within the structure.
*
* Given a pointer to a member of a structure, this macro does
* typechecking and figures out the offset to the enclosing type.
*
* Example:
* struct foo {
* int fielda, fieldb;
* // ...
* };
* struct info {
* int some_other_field;
* struct foo my_foo;
* };
*
* static struct info *foo_to_info(struct foo *foo)
* {
* size_t off = container_off(struct info, my_foo);
* return (void *)((char *)foo - off);
* }
*/
#define container_off(containing_type, member) \
offsetof(containing_type, member)
/**
* container_of_var - get pointer to enclosing structure using a variable
* @member_ptr: pointer to the structure member
* @container_var: a pointer of same type as this member's container
* @member: the name of this member within the structure.
*
* Given a pointer to a member of a structure, this macro does pointer
* subtraction to return the pointer to the enclosing type.
*
* Example:
* static struct info *foo_to_i(struct foo *foo)
* {
* struct info *i = container_of_var(foo, i, my_foo);
* return i;
* }
*/
#if HAVE_TYPEOF
#define container_of_var(member_ptr, container_var, member) \
container_of(member_ptr, typeof(*container_var), member)
#else
#define container_of_var(member_ptr, container_var, member) \
((void *)((char *)(member_ptr) - \
container_off_var(container_var, member)))
#endif
/**
* container_off_var - get offset of a field in enclosing structure
* @container_var: a pointer to a container structure
* @member: the name of a member within the structure.
*
* Given (any) pointer to a structure and a its member name, this
* macro does pointer subtraction to return offset of member in a
* structure memory layout.
*
*/
#if HAVE_TYPEOF
#define container_off_var(var, member) \
container_off(typeof(*var), member)
#else
#define container_off_var(var, member) \
((char *)&(var)->member - (char *)(var))
#endif
#endif /* CCAN_CONTAINER_OF_H */