From 316095eb41ed22da808b5826404c398917c83c89 Mon Sep 17 00:00:00 2001 From: Ruifeng Wang Date: Thu, 18 Jul 2019 14:22:30 +0800 Subject: [PATCH] lpm: use atomic store to avoid partial update Compiler could generate non-atomic stores for whole table entry updating. This may cause incorrect nexthop to be returned, if the byte with valid flag is updated prior to the byte with nexthop is updated. Besides, field by field updating of table entries follow read-modify-write sequences. The operations are not atomic, nor efficient. And could cause entries out of synchronization. Changed to use atomic store to update whole table entry. Suggested-by: Vladimir Medvedkin Suggested-by: Gavin Hu Signed-off-by: Ruifeng Wang Reviewed-by: Gavin Hu Acked-by: Vladimir Medvedkin --- lib/librte_lpm/rte_lpm.c | 138 +++++++++++++++++++++++++++++---------- 1 file changed, 104 insertions(+), 34 deletions(-) diff --git a/lib/librte_lpm/rte_lpm.c b/lib/librte_lpm/rte_lpm.c index 5bd8ab9360..3a929a1b16 100644 --- a/lib/librte_lpm/rte_lpm.c +++ b/lib/librte_lpm/rte_lpm.c @@ -655,11 +655,19 @@ tbl8_alloc_v20(struct rte_lpm_tbl_entry_v20 *tbl8) tbl8_entry = &tbl8[group_idx * RTE_LPM_TBL8_GROUP_NUM_ENTRIES]; /* If a free tbl8 group is found clean it and set as VALID. */ if (!tbl8_entry->valid_group) { + struct rte_lpm_tbl_entry_v20 new_tbl8_entry = { + .valid = INVALID, + .depth = 0, + .valid_group = VALID, + }; + new_tbl8_entry.next_hop = 0; + memset(&tbl8_entry[0], 0, RTE_LPM_TBL8_GROUP_NUM_ENTRIES * sizeof(tbl8_entry[0])); - tbl8_entry->valid_group = VALID; + __atomic_store(tbl8_entry, &new_tbl8_entry, + __ATOMIC_RELAXED); /* Return group index for allocated tbl8 group. */ return group_idx; @@ -681,11 +689,19 @@ tbl8_alloc_v1604(struct rte_lpm_tbl_entry *tbl8, uint32_t number_tbl8s) tbl8_entry = &tbl8[group_idx * RTE_LPM_TBL8_GROUP_NUM_ENTRIES]; /* If a free tbl8 group is found clean it and set as VALID. */ if (!tbl8_entry->valid_group) { + struct rte_lpm_tbl_entry new_tbl8_entry = { + .next_hop = 0, + .valid = INVALID, + .depth = 0, + .valid_group = VALID, + }; + memset(&tbl8_entry[0], 0, RTE_LPM_TBL8_GROUP_NUM_ENTRIES * sizeof(tbl8_entry[0])); - tbl8_entry->valid_group = VALID; + __atomic_store(tbl8_entry, &new_tbl8_entry, + __ATOMIC_RELAXED); /* Return group index for allocated tbl8 group. */ return group_idx; @@ -700,14 +716,25 @@ static void tbl8_free_v20(struct rte_lpm_tbl_entry_v20 *tbl8, uint32_t tbl8_group_start) { /* Set tbl8 group invalid*/ - tbl8[tbl8_group_start].valid_group = INVALID; + struct rte_lpm_tbl_entry_v20 zero_tbl8_entry = { + .valid = INVALID, + .depth = 0, + .valid_group = INVALID, + }; + zero_tbl8_entry.next_hop = 0; + + __atomic_store(&tbl8[tbl8_group_start], &zero_tbl8_entry, + __ATOMIC_RELAXED); } static void tbl8_free_v1604(struct rte_lpm_tbl_entry *tbl8, uint32_t tbl8_group_start) { /* Set tbl8 group invalid*/ - tbl8[tbl8_group_start].valid_group = INVALID; + struct rte_lpm_tbl_entry zero_tbl8_entry = {0}; + + __atomic_store(&tbl8[tbl8_group_start], &zero_tbl8_entry, + __ATOMIC_RELAXED); } static __rte_noinline int32_t @@ -768,7 +795,9 @@ add_depth_small_v20(struct rte_lpm_v20 *lpm, uint32_t ip, uint8_t depth, * Setting tbl8 entry in one go to avoid * race conditions */ - lpm->tbl8[j] = new_tbl8_entry; + __atomic_store(&lpm->tbl8[j], + &new_tbl8_entry, + __ATOMIC_RELAXED); continue; } @@ -838,7 +867,9 @@ add_depth_small_v1604(struct rte_lpm *lpm, uint32_t ip, uint8_t depth, * Setting tbl8 entry in one go to avoid * race conditions */ - lpm->tbl8[j] = new_tbl8_entry; + __atomic_store(&lpm->tbl8[j], + &new_tbl8_entry, + __ATOMIC_RELAXED); continue; } @@ -876,9 +907,14 @@ add_depth_big_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked, uint8_t depth, /* Set tbl8 entry. */ for (i = tbl8_index; i < (tbl8_index + tbl8_range); i++) { - lpm->tbl8[i].depth = depth; - lpm->tbl8[i].next_hop = next_hop; - lpm->tbl8[i].valid = VALID; + struct rte_lpm_tbl_entry_v20 new_tbl8_entry = { + .valid = VALID, + .depth = depth, + .valid_group = lpm->tbl8[i].valid_group, + }; + new_tbl8_entry.next_hop = next_hop; + __atomic_store(&lpm->tbl8[i], &new_tbl8_entry, + __ATOMIC_RELAXED); } /* @@ -913,19 +949,29 @@ add_depth_big_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked, uint8_t depth, /* Populate new tbl8 with tbl24 value. */ for (i = tbl8_group_start; i < tbl8_group_end; i++) { - lpm->tbl8[i].valid = VALID; - lpm->tbl8[i].depth = lpm->tbl24[tbl24_index].depth; - lpm->tbl8[i].next_hop = - lpm->tbl24[tbl24_index].next_hop; + struct rte_lpm_tbl_entry_v20 new_tbl8_entry = { + .valid = VALID, + .depth = lpm->tbl24[tbl24_index].depth, + .valid_group = lpm->tbl8[i].valid_group, + }; + new_tbl8_entry.next_hop = + lpm->tbl24[tbl24_index].next_hop; + __atomic_store(&lpm->tbl8[i], &new_tbl8_entry, + __ATOMIC_RELAXED); } tbl8_index = tbl8_group_start + (ip_masked & 0xFF); /* Insert new rule into the tbl8 entry. */ for (i = tbl8_index; i < tbl8_index + tbl8_range; i++) { - lpm->tbl8[i].valid = VALID; - lpm->tbl8[i].depth = depth; - lpm->tbl8[i].next_hop = next_hop; + struct rte_lpm_tbl_entry_v20 new_tbl8_entry = { + .valid = VALID, + .depth = depth, + .valid_group = lpm->tbl8[i].valid_group, + }; + new_tbl8_entry.next_hop = next_hop; + __atomic_store(&lpm->tbl8[i], &new_tbl8_entry, + __ATOMIC_RELAXED); } /* @@ -966,7 +1012,8 @@ add_depth_big_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked, uint8_t depth, * Setting tbl8 entry in one go to avoid race * condition */ - lpm->tbl8[i] = new_tbl8_entry; + __atomic_store(&lpm->tbl8[i], &new_tbl8_entry, + __ATOMIC_RELAXED); continue; } @@ -1004,9 +1051,14 @@ add_depth_big_v1604(struct rte_lpm *lpm, uint32_t ip_masked, uint8_t depth, /* Set tbl8 entry. */ for (i = tbl8_index; i < (tbl8_index + tbl8_range); i++) { - lpm->tbl8[i].depth = depth; - lpm->tbl8[i].next_hop = next_hop; - lpm->tbl8[i].valid = VALID; + struct rte_lpm_tbl_entry new_tbl8_entry = { + .valid = VALID, + .depth = depth, + .valid_group = lpm->tbl8[i].valid_group, + .next_hop = next_hop, + }; + __atomic_store(&lpm->tbl8[i], &new_tbl8_entry, + __ATOMIC_RELAXED); } /* @@ -1044,19 +1096,28 @@ add_depth_big_v1604(struct rte_lpm *lpm, uint32_t ip_masked, uint8_t depth, /* Populate new tbl8 with tbl24 value. */ for (i = tbl8_group_start; i < tbl8_group_end; i++) { - lpm->tbl8[i].valid = VALID; - lpm->tbl8[i].depth = lpm->tbl24[tbl24_index].depth; - lpm->tbl8[i].next_hop = - lpm->tbl24[tbl24_index].next_hop; + struct rte_lpm_tbl_entry new_tbl8_entry = { + .valid = VALID, + .depth = lpm->tbl24[tbl24_index].depth, + .valid_group = lpm->tbl8[i].valid_group, + .next_hop = lpm->tbl24[tbl24_index].next_hop, + }; + __atomic_store(&lpm->tbl8[i], &new_tbl8_entry, + __ATOMIC_RELAXED); } tbl8_index = tbl8_group_start + (ip_masked & 0xFF); /* Insert new rule into the tbl8 entry. */ for (i = tbl8_index; i < tbl8_index + tbl8_range; i++) { - lpm->tbl8[i].valid = VALID; - lpm->tbl8[i].depth = depth; - lpm->tbl8[i].next_hop = next_hop; + struct rte_lpm_tbl_entry new_tbl8_entry = { + .valid = VALID, + .depth = depth, + .valid_group = lpm->tbl8[i].valid_group, + .next_hop = next_hop, + }; + __atomic_store(&lpm->tbl8[i], &new_tbl8_entry, + __ATOMIC_RELAXED); } /* @@ -1101,7 +1162,8 @@ add_depth_big_v1604(struct rte_lpm *lpm, uint32_t ip_masked, uint8_t depth, * Setting tbl8 entry in one go to avoid race * condition */ - lpm->tbl8[i] = new_tbl8_entry; + __atomic_store(&lpm->tbl8[i], &new_tbl8_entry, + __ATOMIC_RELAXED); continue; } @@ -1394,7 +1456,9 @@ delete_depth_small_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked, RTE_LPM_TBL8_GROUP_NUM_ENTRIES); j++) { if (lpm->tbl8[j].depth <= depth) - lpm->tbl8[j] = new_tbl8_entry; + __atomic_store(&lpm->tbl8[j], + &new_tbl8_entry, + __ATOMIC_RELAXED); } } } @@ -1491,7 +1555,9 @@ delete_depth_small_v1604(struct rte_lpm *lpm, uint32_t ip_masked, RTE_LPM_TBL8_GROUP_NUM_ENTRIES); j++) { if (lpm->tbl8[j].depth <= depth) - lpm->tbl8[j] = new_tbl8_entry; + __atomic_store(&lpm->tbl8[j], + &new_tbl8_entry, + __ATOMIC_RELAXED); } } } @@ -1647,7 +1713,8 @@ delete_depth_big_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked, */ for (i = tbl8_index; i < (tbl8_index + tbl8_range); i++) { if (lpm->tbl8[i].depth <= depth) - lpm->tbl8[i] = new_tbl8_entry; + __atomic_store(&lpm->tbl8[i], &new_tbl8_entry, + __ATOMIC_RELAXED); } } @@ -1678,7 +1745,8 @@ delete_depth_big_v20(struct rte_lpm_v20 *lpm, uint32_t ip_masked, /* Set tbl24 before freeing tbl8 to avoid race condition. * Prevent the free of the tbl8 group from hoisting. */ - lpm->tbl24[tbl24_index] = new_tbl24_entry; + __atomic_store(&lpm->tbl24[tbl24_index], &new_tbl24_entry, + __ATOMIC_RELAXED); __atomic_thread_fence(__ATOMIC_RELEASE); tbl8_free_v20(lpm->tbl8, tbl8_group_start); } @@ -1731,7 +1799,8 @@ delete_depth_big_v1604(struct rte_lpm *lpm, uint32_t ip_masked, */ for (i = tbl8_index; i < (tbl8_index + tbl8_range); i++) { if (lpm->tbl8[i].depth <= depth) - lpm->tbl8[i] = new_tbl8_entry; + __atomic_store(&lpm->tbl8[i], &new_tbl8_entry, + __ATOMIC_RELAXED); } } @@ -1762,7 +1831,8 @@ delete_depth_big_v1604(struct rte_lpm *lpm, uint32_t ip_masked, /* Set tbl24 before freeing tbl8 to avoid race condition. * Prevent the free of the tbl8 group from hoisting. */ - lpm->tbl24[tbl24_index] = new_tbl24_entry; + __atomic_store(&lpm->tbl24[tbl24_index], &new_tbl24_entry, + __ATOMIC_RELAXED); __atomic_thread_fence(__ATOMIC_RELEASE); tbl8_free_v1604(lpm->tbl8, tbl8_group_start); }