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author | Eric Wong <mwrap-perl@80x24.org> | 2022-09-03 11:18:28 +0000 |
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committer | Eric Wong <e@80x24.org> | 2022-09-04 07:02:13 +0000 |
commit | e701ba4399d3ed2c71d3bff0af285011b3c301d5 (patch) | |
tree | 07734f586613135e7f1e57ae51270deb68fccc7f | |
parent | 4d6a5b449896cefae1406f1a042e6308c47a9d8b (diff) | |
download | mwrap-e701ba4399d3ed2c71d3bff0af285011b3c301d5.tar.gz |
urcu v0.11.4+ introduced commit 7ca7fe9c03 (Make temporary variable in _rcu_dereference non-const, 2021-07-29) which conflicts with our use of _LGPL_SOURCE. In retrospect, CMM_LOAD_SHARED and CMM_STORE_SHARED seem sufficient for our use of the `totals' cds_lfht pointer since the constructur should always fire before any threads are running. This is fixed in urcu v0.12.4 and v0.13.2 (released 2022-08-18) but I suspect older versions will live on in enterprise/LTS distros for a long while. Link: https://lore.kernel.org/lttng-dev/20220809181927.GA3718@dcvr/
-rw-r--r-- | Mwrap.xs | 16 |
1 files changed, 8 insertions, 8 deletions
@@ -298,7 +298,7 @@ static struct src_loc *totals_add_rcu(struct src_loc *k) struct cds_lfht *t; again: - t = rcu_dereference(totals); + t = CMM_LOAD_SHARED(totals); if (!t) goto out_unlock; cds_lfht_lookup(t, k->hval, loc_eq, k, &iter); cur = cds_lfht_iter_get_node(&iter); @@ -341,7 +341,7 @@ update_stats_rcu_lock(size_t *generation, size_t size, uintptr_t caller) static const size_t xlen = sizeof(caller); char *dst; const COP *cop; - struct cds_lfht *t = rcu_dereference(totals); + struct cds_lfht *t = CMM_LOAD_SHARED(totals); if (caa_unlikely(!t)) return 0; if (locating++) goto out; /* do not recurse into another *alloc */ @@ -684,7 +684,7 @@ static void *dump_to_file(struct dump_arg *a) ++locating; rcu_read_lock(); - t = rcu_dereference(totals); + t = CMM_LOAD_SHARED(totals); if (!t) goto out_unlock; cds_lfht_for_each_entry(t, &iter, l, hnode) { @@ -805,8 +805,8 @@ BOOT: #ifndef PERL_IMPLICIT_CONTEXT root_locating = &locating; #endif - totals = lfht_new(); - if (!totals) + CMM_STORE_SHARED(totals, lfht_new()); + if (!CMM_LOAD_SHARED(totals)) fprintf(stderr, "failed to allocate totals table\n"); PROTOTYPES: ENABLE @@ -851,7 +851,7 @@ PREINIT: CODE: ++locating; rcu_read_lock(); - t = rcu_dereference(totals); + t = CMM_LOAD_SHARED(totals); if (t) { bool err = false; @@ -903,7 +903,7 @@ CODE: uatomic_set(&total_bytes_dec, 0); rcu_read_lock(); - t = rcu_dereference(totals); + t = CMM_LOAD_SHARED(totals); cds_lfht_for_each_entry(t, &iter, l, hnode) { uatomic_set(&l->total, 0); uatomic_set(&l->allocations, 0); @@ -949,7 +949,7 @@ CODE: XSRETURN_UNDEF; rcu_read_lock(); - t = rcu_dereference(totals); + t = CMM_LOAD_SHARED(totals); if (!t) goto out_unlock; cds_lfht_lookup(t, k->hval, loc_eq, k, &iter); |