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authorBjörn Gustavsson <[email protected]>2018-10-05 13:15:49 +0200
committerBjörn Gustavsson <[email protected]>2018-10-24 12:59:48 +0200
commitd6e8bddde0887894ae70cc2c6d4230532801bf97 (patch)
tree6361b3a9a813c467c639ac94c53cad7121931e5f
parentc37f7a2215646c85c1ae12303f07bc9bc27b75ae (diff)
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Extend the sharing-preserving routines to optionally copy literals
In the implementation of the zero-copying term storage, we want to preserve sharing, but not copy literals because the modules holding the literals could be unloaded under our feet.
-rw-r--r--erts/emulator/beam/copy.c10
-rw-r--r--erts/emulator/beam/global.h2
2 files changed, 8 insertions, 4 deletions
diff --git a/erts/emulator/beam/copy.c b/erts/emulator/beam/copy.c
index e7bfd04b73..e7bd046e18 100644
--- a/erts/emulator/beam/copy.c
+++ b/erts/emulator/beam/copy.c
@@ -1074,6 +1074,7 @@ Uint copy_shared_calculate(Eterm obj, erts_shcopy_t *info)
Eterm* ptr;
Eterm *lit_purge_ptr = info->lit_purge_ptr;
Uint lit_purge_sz = info->lit_purge_sz;
+ int copy_literals = info->copy_literals;
#ifdef DEBUG
Eterm mypid = erts_get_current_pid();
#endif
@@ -1119,7 +1120,7 @@ Uint copy_shared_calculate(Eterm obj, erts_shcopy_t *info)
/* off heap list pointers are copied verbatim */
if (erts_is_literal(obj,ptr)) {
VERBOSE(DEBUG_SHCOPY, ("[pid=%T] bypassed copying %p is %T\n", mypid, ptr, obj));
- if (in_literal_purge_area(ptr))
+ if (copy_literals || in_literal_purge_area(ptr))
info->literal_size += size_object(obj);
goto pop_next;
}
@@ -1170,7 +1171,7 @@ Uint copy_shared_calculate(Eterm obj, erts_shcopy_t *info)
/* off heap pointers to boxes are copied verbatim */
if (erts_is_literal(obj,ptr)) {
VERBOSE(DEBUG_SHCOPY, ("[pid=%T] bypassed copying %p is %T\n", mypid, ptr, obj));
- if (in_literal_purge_area(ptr))
+ if (copy_literals || in_literal_purge_area(ptr))
info->literal_size += size_object(obj);
goto pop_next;
}
@@ -1338,6 +1339,7 @@ Uint copy_shared_perform(Eterm obj, Uint size, erts_shcopy_t *info,
unsigned remaining;
Eterm *lit_purge_ptr = info->lit_purge_ptr;
Uint lit_purge_sz = info->lit_purge_sz;
+ int copy_literals = info->copy_literals;
#ifdef DEBUG
Eterm mypid = erts_get_current_pid();
Eterm saved_obj = obj;
@@ -1387,7 +1389,7 @@ Uint copy_shared_perform(Eterm obj, Uint size, erts_shcopy_t *info,
ptr = list_val(obj);
/* off heap list pointers are copied verbatim */
if (erts_is_literal(obj,ptr)) {
- if (!in_literal_purge_area(ptr)) {
+ if (!(copy_literals || in_literal_purge_area(ptr))) {
*resp = obj;
} else {
Uint bsz = 0;
@@ -1455,7 +1457,7 @@ Uint copy_shared_perform(Eterm obj, Uint size, erts_shcopy_t *info,
ptr = boxed_val(obj);
/* off heap pointers to boxes are copied verbatim */
if (erts_is_literal(obj,ptr)) {
- if (!in_literal_purge_area(ptr)) {
+ if (!(copy_literals || in_literal_purge_area(ptr))) {
*resp = obj;
} else {
Uint bsz = 0;
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 21ae205237..9fc5abbf68 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -1001,6 +1001,7 @@ typedef struct {
Uint literal_size;
Eterm *lit_purge_ptr;
Uint lit_purge_sz;
+ int copy_literals;
} erts_shcopy_t;
#define INITIALIZE_SHCOPY(info) \
@@ -1010,6 +1011,7 @@ typedef struct {
info.bitstore_start = info.bitstore_default; \
info.shtable_start = info.shtable_default; \
info.literal_size = 0; \
+ info.copy_literals = 0; \
if (larea__) { \
info.lit_purge_ptr = &larea__->start[0]; \
info.lit_purge_sz = larea__->end - info.lit_purge_ptr; \