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Mallctl: Add arenas.lookup

Implement a new mallctl operation that allows looking up the arena a
region of memory belongs to.
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Latchesar Ionkov authored and interwq committed May 1, 2018
1 parent 6df9060 commit a32b7bd5676e669821d15d319f686c3add451f4b
Showing with 59 additions and 1 deletion.
  1. +9 −0 doc/jemalloc.xml.in
  2. +33 −1 src/ctl.c
  3. +17 −0 test/unit/mallctl.c
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@@ -2130,6 +2130,15 @@ struct extent_hooks_s {
and return the new arena index.</para></listitem>
</varlistentry>
<varlistentry id="arenas.lookup">
<term>
<mallctl>arenas.lookup</mallctl>
(<type>unsigned</type>, <type>void*</type>)
<literal>rw</literal>
</term>
<listitem><para>Index of the arena to which an allocation belongs to.</para></listitem>
</varlistentry>
<varlistentry id="prof.thread_active_init">
<term>
<mallctl>prof.thread_active_init</mallctl>
View
@@ -139,6 +139,7 @@ CTL_PROTO(arenas_nbins)
CTL_PROTO(arenas_nhbins)
CTL_PROTO(arenas_nlextents)
CTL_PROTO(arenas_create)
CTL_PROTO(arenas_lookup)
CTL_PROTO(prof_thread_active_init)
CTL_PROTO(prof_active)
CTL_PROTO(prof_dump)
@@ -373,7 +374,8 @@ static const ctl_named_node_t arenas_node[] = {
{NAME("bin"), CHILD(indexed, arenas_bin)},
{NAME("nlextents"), CTL(arenas_nlextents)},
{NAME("lextent"), CHILD(indexed, arenas_lextent)},
{NAME("create"), CTL(arenas_create)}
{NAME("create"), CTL(arenas_create)},
{NAME("lookup"), CTL(arenas_lookup)}
};
static const ctl_named_node_t prof_node[] = {
@@ -2471,6 +2473,36 @@ arenas_create_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
return ret;
}
static int
arenas_lookup_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
size_t *oldlenp, void *newp, size_t newlen) {
int ret;
unsigned arena_ind;
void *ptr;
extent_t *extent;
arena_t *arena;
ptr = NULL;
ret = EINVAL;
malloc_mutex_lock(tsd_tsdn(tsd), &ctl_mtx);
WRITE(ptr, void *);
extent = iealloc(tsd_tsdn(tsd), ptr);
if (extent == NULL)
goto label_return;
arena = extent_arena_get(extent);
if (arena == NULL)
goto label_return;
arena_ind = arena_ind_get(arena);
READ(arena_ind, unsigned);
ret = 0;
label_return:
malloc_mutex_unlock(tsd_tsdn(tsd), &ctl_mtx);
return ret;
}
/******************************************************************************/
static int
View
@@ -738,6 +738,22 @@ TEST_BEGIN(test_arenas_create) {
}
TEST_END
TEST_BEGIN(test_arenas_lookup) {
unsigned arena, arena1;
void *ptr;
size_t sz = sizeof(unsigned);
assert_d_eq(mallctl("arenas.create", (void *)&arena, &sz, NULL, 0), 0,
"Unexpected mallctl() failure");
ptr = mallocx(42, MALLOCX_ARENA(arena) | MALLOCX_TCACHE_NONE);
assert_ptr_not_null(ptr, "Unexpected mallocx() failure");
assert_d_eq(mallctl("arenas.lookup", &arena1, &sz, &ptr, sizeof(ptr)),
0, "Unexpected mallctl() failure");
assert_u_eq(arena, arena1, "Unexpected arena index");
dallocx(ptr, 0);
}
TEST_END
TEST_BEGIN(test_stats_arenas) {
#define TEST_STATS_ARENAS(t, name) do { \
t name; \
@@ -784,5 +800,6 @@ main(void) {
test_arenas_bin_constants,
test_arenas_lextent_constants,
test_arenas_create,
test_arenas_lookup,
test_stats_arenas);
}

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