diff options
Diffstat (limited to 'erts/emulator/sys/common')
| -rw-r--r-- | erts/emulator/sys/common/erl_check_io.c | 78 | ||||
| -rw-r--r-- | erts/emulator/sys/common/erl_mmap.h | 57 |
2 files changed, 106 insertions, 29 deletions
diff --git a/erts/emulator/sys/common/erl_check_io.c b/erts/emulator/sys/common/erl_check_io.c index c681fa481f..b4609007c9 100644 --- a/erts/emulator/sys/common/erl_check_io.c +++ b/erts/emulator/sys/common/erl_check_io.c @@ -993,7 +993,7 @@ enif_select(ErlNifEnv* env, ctl_op = ERTS_POLL_OP_DEL; } else { - on = 1; + on = !(mode & ERL_NIF_SELECT_CANCEL); ASSERT(mode); if (mode & ERL_DRV_READ) { ctl_events |= ERTS_POLL_EV_IN; @@ -1119,38 +1119,51 @@ enif_select(ErlNifEnv* env, ret = 0; } else { /* off */ + ret = 0; if (state->type == ERTS_EV_TYPE_NIF) { - state->driver.nif->in.pid = NIL; - state->driver.nif->out.pid = NIL; - } - ASSERT(state->events==0); - if (!wake_poller) { - /* - * Safe to close fd now as it is not in pollset - * or there was no need to eject fd (kernel poll) - */ - if (state->type == ERTS_EV_TYPE_NIF) { - ASSERT(state->driver.stop.resource == resource); - call_stop = CALL_STOP_AND_RELEASE; - state->driver.stop.resource = NULL; + if (mode & ERL_NIF_SELECT_READ + && is_not_nil(state->driver.nif->in.pid)) { + state->driver.nif->in.pid = NIL; + ret |= ERL_NIF_SELECT_READ_CANCELLED; } - else { - ASSERT(!state->driver.stop.resource); - call_stop = CALL_STOP; + if (mode & ERL_NIF_SELECT_WRITE + && is_not_nil(state->driver.nif->out.pid)) { + state->driver.nif->out.pid = NIL; + ret |= ERL_NIF_SELECT_WRITE_CANCELLED; } - state->type = ERTS_EV_TYPE_NONE; - ret = ERL_NIF_SELECT_STOP_CALLED; } - else { - /* Not safe to close fd, postpone stop_select callback. */ - if (state->type == ERTS_EV_TYPE_NONE) { - ASSERT(!state->driver.stop.resource); - state->driver.stop.resource = resource; - enif_keep_resource(resource); + if (mode & ERL_NIF_SELECT_STOP) { + ASSERT(state->events==0); + if (!wake_poller) { + /* + * Safe to close fd now as it is not in pollset + * or there was no need to eject fd (kernel poll) + */ + if (state->type == ERTS_EV_TYPE_NIF) { + ASSERT(state->driver.stop.resource == resource); + call_stop = CALL_STOP_AND_RELEASE; + state->driver.stop.resource = NULL; + } + else { + ASSERT(!state->driver.stop.resource); + call_stop = CALL_STOP; + } + state->type = ERTS_EV_TYPE_NONE; + ret |= ERL_NIF_SELECT_STOP_CALLED; + } + else { + /* Not safe to close fd, postpone stop_select callback. */ + if (state->type == ERTS_EV_TYPE_NONE) { + ASSERT(!state->driver.stop.resource); + state->driver.stop.resource = resource; + enif_keep_resource(resource); + } + state->type = ERTS_EV_TYPE_STOP_NIF; + ret |= ERL_NIF_SELECT_STOP_SCHEDULED; } - state->type = ERTS_EV_TYPE_STOP_NIF; - ret = ERL_NIF_SELECT_STOP_SCHEDULED; } + else + ASSERT(mode & ERL_NIF_SELECT_CANCEL); } done: @@ -1328,7 +1341,8 @@ print_nif_select_op(erts_dsprintf_buf_t *dsbufp, (int) fd, mode & ERL_NIF_SELECT_READ ? " READ" : "", mode & ERL_NIF_SELECT_WRITE ? " WRITE" : "", - mode & ERL_NIF_SELECT_STOP ? " STOP" : "", + (mode & ERL_NIF_SELECT_STOP ? " STOP" + : (mode & ERL_NIF_SELECT_CANCEL ? " CANCEL" : "")), resource->type->module, resource->type->name, ref); @@ -2448,10 +2462,16 @@ drvmode2str(int mode) { static ERTS_INLINE char * nifmode2str(enum ErlNifSelectFlags mode) { + if (mode & ERL_NIF_SELECT_STOP) + return "STOP"; switch (mode) { case ERL_NIF_SELECT_READ: return "READ"; case ERL_NIF_SELECT_WRITE: return "WRITE"; - case ERL_NIF_SELECT_STOP: return "STOP"; + case ERL_NIF_SELECT_READ|ERL_NIF_SELECT_WRITE: return "READ|WRITE"; + case ERL_NIF_SELECT_CANCEL|ERL_NIF_SELECT_READ: return "CANCEL|READ"; + case ERL_NIF_SELECT_CANCEL|ERL_NIF_SELECT_WRITE: return "CANCEL|WRITE"; + case ERL_NIF_SELECT_CANCEL|ERL_NIF_SELECT_READ|ERL_NIF_SELECT_WRITE: + return "CANCEL|READ|WRITE"; default: return "UNKNOWN"; } } diff --git a/erts/emulator/sys/common/erl_mmap.h b/erts/emulator/sys/common/erl_mmap.h index 539daea419..e1ff0fe80a 100644 --- a/erts/emulator/sys/common/erl_mmap.h +++ b/erts/emulator/sys/common/erl_mmap.h @@ -176,4 +176,61 @@ void hard_dbg_remove_mseg(void* seg, UWord sz); #endif /* HAVE_ERTS_MMAP */ +/* Marks the given memory region as unused without freeing it, letting the OS + * reclaim its physical memory with the promise that we'll get it back (without + * its contents) the next time it's accessed. */ +ERTS_GLB_INLINE void erts_mem_discard(void *p, UWord size); + +#if ERTS_GLB_INLINE_INCL_FUNC_DEF + +#ifdef VALGRIND + #include <valgrind/memcheck.h> + + ERTS_GLB_INLINE void erts_mem_discard(void *ptr, UWord size) { + VALGRIND_MAKE_MEM_UNDEFINED(ptr, size); + } +#elif defined(DEBUG) + /* Try to provoke crashes by filling the discard region with garbage. It's + * extremely hard to find bugs where we've discarded too much, as the + * region often retains its old contents if it's accessed before the OS + * reclaims it. */ + ERTS_GLB_INLINE void erts_mem_discard(void *ptr, UWord size) { + static const char pattern[] = "DISCARDED"; + char *data; + int i; + + for(i = 0, data = ptr; i < size; i++) { + data[i] = pattern[i % sizeof(pattern)]; + } + } +#elif defined(HAVE_SYS_MMAN_H) + #include <sys/mman.h> + + ERTS_GLB_INLINE void erts_mem_discard(void *ptr, UWord size) { + #ifdef MADV_FREE + /* This is preferred as it doesn't necessarily free the pages right + * away, which is a bit faster than MADV_DONTNEED. */ + madvise(ptr, size, MADV_FREE); + #else + madvise(ptr, size, MADV_DONTNEED); + #endif + } +#elif defined(_WIN32) + #include <winbase.h> + + /* MEM_RESET is defined on all supported versions of Windows, and has the + * same semantics as MADV_FREE. */ + ERTS_GLB_INLINE void erts_mem_discard(void *ptr, UWord size) { + VirtualAlloc(ptr, size, MEM_RESET, PAGE_READWRITE); + } +#else + /* Dummy implementation. */ + ERTS_GLB_INLINE void erts_mem_discard(void *ptr, UWord size) { + (void)ptr; + (void)size; + } +#endif + +#endif /* ERTS_GLB_INLINE_INCL_FUNC_DEF */ + #endif /* ERL_MMAP_H__ */ |