diff options
| author | Jemma Issroff <[email protected]> | 2022-10-03 13:52:40 -0400 |
|---|---|---|
| committer | Aaron Patterson <[email protected]> | 2022-10-11 08:40:56 -0700 |
| commit | 913979bede2a1b79109fa2072352882560d55fe0 () | |
| tree | b039ef9760ff7b1bf397fd9cac648cc219032cd6 /vm_callinfo.h | |
| parent | ad63b668e22e21c352b852f3119ae98a7acf99f1 (diff) | |
Make inline cache reads / writes atomic with object shapes
Prior to this commit, we were reading and writing ivar index and shape ID in inline caches in two separate instructions when getting and setting ivars. This meant there was a race condition with ractors and these caches where one ractor could change a value in the cache while another was still reading from it. This commit instead reads and writes shape ID and ivar index to inline caches atomically so there is no longer a race condition. Co-Authored-By: Aaron Patterson <[email protected]> Co-Authored-By: John Hawthorn <[email protected]>
| -rw-r--r-- | vm_callinfo.h | 81 |
1 files changed, 22 insertions, 59 deletions
@@ -286,8 +286,7 @@ struct rb_callcache { union { struct { - const attr_index_t index; - shape_id_t dest_shape_id; } attr; const enum method_missing_reason method_missing_reason; /* used by method_missing */ VALUE v; @@ -307,9 +306,7 @@ vm_cc_attr_index_initialize(const struct rb_callcache *cc, shape_id_t shape_id) { VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache)); VM_ASSERT(cc != vm_cc_empty()); - IMEMO_SET_CACHED_SHAPE_ID((VALUE)cc, shape_id); - *(attr_index_t *)&cc->aux_.attr.index = 0; - *(shape_id_t *)&cc->aux_.attr.dest_shape_id = shape_id; } static inline const struct rb_callcache * @@ -374,29 +371,7 @@ static inline attr_index_t vm_cc_attr_index(const struct rb_callcache *cc) { VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache)); - return cc->aux_.attr.index - 1; -} - -static inline bool -vm_cc_attr_index_p(const struct rb_callcache *cc) -{ - VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache)); - return cc->aux_.attr.index != 0; -} - -static inline shape_id_t -vm_cc_attr_index_source_shape_id(const struct rb_callcache *cc) -{ - VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache)); - - return IMEMO_CACHED_SHAPE_ID((VALUE)cc); -} - -static inline shape_id_t -vm_cc_attr_shape_id(const struct rb_callcache *cc) -{ - VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache)); - return vm_cc_attr_index_source_shape_id(cc); } static inline shape_id_t @@ -404,37 +379,31 @@ vm_cc_attr_index_dest_shape_id(const struct rb_callcache *cc) { VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache)); - return cc->aux_.attr.dest_shape_id; -} - -static inline attr_index_t -vm_ic_attr_index(const struct iseq_inline_iv_cache_entry *ic) -{ - return ic->attr_index - 1; -} - -static inline bool -vm_ic_attr_index_p(const struct iseq_inline_iv_cache_entry *ic) -{ - return ic->attr_index > 0; } -static inline shape_id_t -vm_ic_attr_shape_id(const struct iseq_inline_iv_cache_entry *ic) { - return ic->source_shape_id; } -static inline shape_id_t -vm_ic_attr_index_source_shape_id(const struct iseq_inline_iv_cache_entry *ic) { - return ic->source_shape_id; } static inline shape_id_t vm_ic_attr_index_dest_shape_id(const struct iseq_inline_iv_cache_entry *ic) { - return ic->dest_shape_id; } static inline unsigned int @@ -479,29 +448,23 @@ vm_cc_call_set(const struct rb_callcache *cc, vm_call_handler call) } static inline void -vm_cc_attr_index_set(const struct rb_callcache *cc, attr_index_t index, shape_id_t source_shape_id, shape_id_t dest_shape_id) { VM_ASSERT(IMEMO_TYPE_P(cc, imemo_callcache)); VM_ASSERT(cc != vm_cc_empty()); - IMEMO_SET_CACHED_SHAPE_ID((VALUE)cc, source_shape_id); - *(attr_index_t *)&cc->aux_.attr.index = (index + 1); - *(shape_id_t *)&cc->aux_.attr.dest_shape_id = dest_shape_id; } static inline void -vm_ic_attr_index_set(const rb_iseq_t *iseq, const struct iseq_inline_iv_cache_entry *ic, attr_index_t index, shape_id_t source_shape_id, shape_id_t dest_shape_id) { - *(shape_id_t *)&ic->source_shape_id = source_shape_id; - *(shape_id_t *)&ic->dest_shape_id = dest_shape_id; - *(attr_index_t *)&ic->attr_index = index + 1; } static inline void vm_ic_attr_index_initialize(const struct iseq_inline_iv_cache_entry *ic, shape_id_t shape_id) { - *(shape_id_t *)&ic->source_shape_id = shape_id; - *(shape_id_t *)&ic->dest_shape_id = shape_id; - *(attr_index_t *)&ic->attr_index = 0; } static inline void |