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author | normal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2014-05-10 23:48:51 +0000 |
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committer | normal <normal@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2014-05-10 23:48:51 +0000 |
commit | f11db2a605d99ef6a0943eba34db355188f8efcb (patch) | |
tree | 277ff70e7cc260d26f3028d89f25d5b4603675b4 /ccan/check_type | |
parent | 3771a370ad64aae87f751751e80d52d02a1735a9 (diff) |
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
Diffstat (limited to 'ccan/check_type')
-rw-r--r-- | ccan/check_type/check_type.h | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/ccan/check_type/check_type.h b/ccan/check_type/check_type.h new file mode 100644 index 0000000000..1f77a535e4 --- /dev/null +++ b/ccan/check_type/check_type.h @@ -0,0 +1,63 @@ +/* CC0 (Public domain) - see ccan/licenses/CC0 file for details */ +#ifndef CCAN_CHECK_TYPE_H +#define CCAN_CHECK_TYPE_H + +/** + * check_type - issue a warning or build failure if type is not correct. + * @expr: the expression whose type we should check (not evaluated). + * @type: the exact type we expect the expression to be. + * + * This macro is usually used within other macros to try to ensure that a macro + * argument is of the expected type. No type promotion of the expression is + * done: an unsigned int is not the same as an int! + * + * check_type() always evaluates to 0. + * + * If your compiler does not support typeof, then the best we can do is fail + * to compile if the sizes of the types are unequal (a less complete check). + * + * Example: + * // They should always pass a 64-bit value to _set_some_value! + * #define set_some_value(expr) \ + * _set_some_value((check_type((expr), uint64_t), (expr))) + */ + +/** + * check_types_match - issue a warning or build failure if types are not same. + * @expr1: the first expression (not evaluated). + * @expr2: the second expression (not evaluated). + * + * This macro is usually used within other macros to try to ensure that + * arguments are of identical types. No type promotion of the expressions is + * done: an unsigned int is not the same as an int! + * + * check_types_match() always evaluates to 0. + * + * If your compiler does not support typeof, then the best we can do is fail + * to compile if the sizes of the types are unequal (a less complete check). + * + * Example: + * // Do subtraction to get to enclosing type, but make sure that + * // pointer is of correct type for that member. + * #define container_of(mbr_ptr, encl_type, mbr) \ + * (check_types_match((mbr_ptr), &((encl_type *)0)->mbr), \ + * ((encl_type *) \ + * ((char *)(mbr_ptr) - offsetof(enclosing_type, mbr)))) + */ +#if HAVE_TYPEOF +#define check_type(expr, type) \ + ((typeof(expr) *)0 != (type *)0) + +#define check_types_match(expr1, expr2) \ + ((typeof(expr1) *)0 != (typeof(expr2) *)0) +#else +#include "ccan/build_assert/build_assert.h" +/* Without typeof, we can only test the sizes. */ +#define check_type(expr, type) \ + BUILD_ASSERT_OR_ZERO(sizeof(expr) == sizeof(type)) + +#define check_types_match(expr1, expr2) \ + BUILD_ASSERT_OR_ZERO(sizeof(expr1) == sizeof(expr2)) +#endif /* HAVE_TYPEOF */ + +#endif /* CCAN_CHECK_TYPE_H */ |