| Title | Collection start reason hard to analyze |
| Status | suspended |
| Priority | nice |
| Assigned user | Gareth Rees |
| Organization | Ravenbrook |
| Description | The function mps_message_gc_start_why [1] returns an English-language description of why the collection started. This is hard to analyze programmatically: (a) have to do string match; (b) no definitive list of reasons. Also needlessly hard to internationalize. |
| Analysis | Internally to the MPS this is just an enumerated number, so we could expose it somehow. GDR 2013-03-08: I propose adding the following to the public interface: /* Garbage collection causes. * Keep in sync with TraceStartWhy* in mpmtypes.h. * Not meant to be used by clients. They should use the macros below. */ enum { _mps_GC_CAUSE_NURSERY_FULL = 1, _mps_GC_CAUSE_DYNAMIC, _mps_GC_CAUSE_OPPORTUNISM, _mps_GC_CAUSE_CLIENT_INCREMENTAL, _mps_GC_CAUSE_CLIENT_BLOCK, _mps_GC_CAUSE_WALK, _mps_GC_CAUSE_EXTENSION, _mps_GC_CAUSE_UNKNOWN }; /* Garbage collection causes. * These are what clients should use. */ #define mps_gc_cause_nursery_full() _mps_GC_CAUSE_NURSERY_FULL #define mps_gc_cause_dynamic() _mps_GC_CAUSE_DYNAMIC #define mps_gc_cause_opportunism() _mps_GC_CAUSE_OPPORTUNISM #define mps_gc_cause_client_incremental() _mps_GC_CAUSE_CLIENT_INCREMENTAL #define mps_gc_cause_client_block() _mps_GC_CAUSE_CLIENT_BLOCK #define mps_gc_cause_walk() _mps_GC_CAUSE_WALK #define mps_gc_cause_extension() _mps_GC_CAUSE_EXTENSION #define mps_gc_cause_unknown() _mps_GC_CAUSE_UNKNOWN typedef int mps_gc_cause_t; /* a garbage collection cause */ extern mps_gc_cause_t mps_message_gc_start_cause(mps_arena_t, mps_message_t); GDR 2013-03-12: RB suggests [2] that we "Defer this until there's a clear requirement" which seems sensible. |
| How found | inspection |
| Evidence | [1] <https://info.ravenbrook.com/project/mp...ollection.html#mps_message_gc_start_why>[2] < https://info.ravenbrook.com/mail/2013/03/12/13-03-07/0/> |
| Observed in | 1.110.0 |
| Created by | Gareth Rees |
| Created on | 2012-10-31 17:10:23 |
| Last modified by | Gareth Rees |
| Last modified on | 2018-07-15 19:18:55 |
| History | 2012-10-31 GDR Created. 2013-03-08 GDR Added proposal. 2013-03-12 GDR Suspend it. |