Lazily initialize dns_compress->table only when compression is enabled (#41189)

diff --git a/CHANGES b/CHANGES
index 0708de06fc0ef803cc1a2d9628585aa3e0b7f4c6..1f0d2cb9ddcd9d27522fc499569a7dc0b18f8e6d 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+4275.  [performance]   Lazily initialize dns_compress->table only when
+                       compression is enabled. [RT #41189]
+
 4274.  [performance]   Speed up typemap processing from text. [RT #41196]
 
 4273.  [bug]           Only call dns_test_begin() and dns_test_end() once each

diff --git a/lib/dns/compress.c b/lib/dns/compress.c
index d826de4fb7ceb489100e698a1f4efba541992f3b..7a2ad36155cbfee44883f474f5d3924a09faae5d 100644 (file)
--- a/lib/dns/compress.c
+++ b/lib/dns/compress.c
@@ -36,25 +36,31 @@
 #define DCTX_MAGIC     ISC_MAGIC('D', 'C', 'T', 'X')
 #define VALID_DCTX(x)  ISC_MAGIC_VALID(x, DCTX_MAGIC)
 
+#define TABLE_READY                                                    \
+       do {                                                            \
+               unsigned int i;                                         \
+                                                                       \
+               if ((cctx->allowed & DNS_COMPRESS_READY) == 0) {        \
+                       cctx->allowed |= DNS_COMPRESS_READY;            \
+                       for (i = 0; i < DNS_COMPRESS_TABLESIZE; i++)    \
+                               cctx->table[i] = NULL;                  \
+               }                                                       \
+       } while (0)
+
 /***
  ***   Compression
  ***/
 
 isc_result_t
 dns_compress_init(dns_compress_t *cctx, int edns, isc_mem_t *mctx) {
-       unsigned int i;
-
        REQUIRE(cctx != NULL);
        REQUIRE(mctx != NULL);  /* See: rdataset.c:towiresorted(). */
 
-       cctx->allowed = 0;
        cctx->edns = edns;
-       for (i = 0; i < DNS_COMPRESS_TABLESIZE; i++)
-               cctx->table[i] = NULL;
        cctx->mctx = mctx;
        cctx->count = 0;
+       cctx->allowed = DNS_COMPRESS_ENABLED;
        cctx->magic = CCTX_MAGIC;
-       cctx->enabled = ISC_TRUE;
        return (ISC_R_SUCCESS);
 }
 
@@ -65,19 +71,21 @@ dns_compress_invalidate(dns_compress_t *cctx) {
 
        REQUIRE(VALID_CCTX(cctx));
 
-       cctx->magic = 0;
-       for (i = 0; i < DNS_COMPRESS_TABLESIZE; i++) {
-               while (cctx->table[i] != NULL) {
-                       node = cctx->table[i];
-                       cctx->table[i] = cctx->table[i]->next;
-                       if ((node->offset & 0x8000) != 0)
-                               isc_mem_put(cctx->mctx, node->r.base,
-                                           node->r.length);
-                       if (node->count < DNS_COMPRESS_INITIALNODES)
-                               continue;
-                       isc_mem_put(cctx->mctx, node, sizeof(*node));
+       if ((cctx->allowed & DNS_COMPRESS_READY) != 0) {
+               for (i = 0; i < DNS_COMPRESS_TABLESIZE; i++) {
+                       while (cctx->table[i] != NULL) {
+                               node = cctx->table[i];
+                               cctx->table[i] = cctx->table[i]->next;
+                               if ((node->offset & 0x8000) != 0)
+                                       isc_mem_put(cctx->mctx, node->r.base,
+                                                   node->r.length);
+                               if (node->count < DNS_COMPRESS_INITIALNODES)
+                                       continue;
+                               isc_mem_put(cctx->mctx, node, sizeof(*node));
+                       }
                }
        }
+       cctx->magic = 0;
        cctx->allowed = 0;
        cctx->edns = -1;
 }
@@ -99,7 +107,7 @@ dns_compress_getmethods(dns_compress_t *cctx) {
 void
 dns_compress_disable(dns_compress_t *cctx) {
        REQUIRE(VALID_CCTX(cctx));
-       cctx->enabled = ISC_FALSE;
+       cctx->allowed &= ~DNS_COMPRESS_ENABLED;
 }
 
 void
@@ -150,9 +158,11 @@ dns_compress_findglobal(dns_compress_t *cctx, const dns_name_t *name,
        REQUIRE(dns_name_isabsolute(name) == ISC_TRUE);
        REQUIRE(offset != NULL);
 
-       if (cctx->enabled == ISC_FALSE)
+       if ((cctx->allowed & DNS_COMPRESS_ENABLED) == 0)
                return (ISC_FALSE);
 
+       TABLE_READY;
+
        if (cctx->count == 0)
                return (ISC_FALSE);
 
@@ -222,9 +232,11 @@ dns_compress_add(dns_compress_t *cctx, const dns_name_t *name,
        REQUIRE(VALID_CCTX(cctx));
        REQUIRE(dns_name_isabsolute(name));
 
-       if (cctx->enabled == ISC_FALSE)
+       if ((cctx->allowed & DNS_COMPRESS_ENABLED) == 0)
                return;
 
+       TABLE_READY;
+
        if (offset >= 0x4000)
                return;
        dns_name_init(&tname, NULL);
@@ -296,6 +308,12 @@ dns_compress_rollback(dns_compress_t *cctx, isc_uint16_t offset) {
 
        REQUIRE(VALID_CCTX(cctx));
 
+       if ((cctx->allowed & DNS_COMPRESS_ENABLED) == 0)
+               return;
+
+       if ((cctx->allowed & DNS_COMPRESS_READY) == 0)
+               return;
+
        for (i = 0; i < DNS_COMPRESS_TABLESIZE; i++) {
                node = cctx->table[i];
                /*

diff --git a/lib/dns/include/dns/compress.h b/lib/dns/include/dns/compress.h
index 1b9f22c6d22068193d7ade8ee21f300d47b965b3..97d820f78e44c0f3ba51f1b41542e8ea4a38d36b 100644 (file)
--- a/lib/dns/include/dns/compress.h
+++ b/lib/dns/include/dns/compress.h
@@ -44,6 +44,9 @@ ISC_LANG_BEGINDECLS
 #define DNS_COMPRESS_GLOBAL14          0x01    /*%< "normal" compression. */
 #define DNS_COMPRESS_ALL               0x01    /*%< all compression. */
 #define DNS_COMPRESS_CASESENSITIVE     0x02    /*%< case sensitive compression. */
+#define DNS_COMPRESS_ENABLED           0x04
+
+#define DNS_COMPRESS_READY             0x80000000
 
 #define DNS_COMPRESS_TABLESIZE 64
 #define DNS_COMPRESS_INITIALNODES 16
@@ -61,7 +64,6 @@ struct dns_compressnode {
 struct dns_compress {
        unsigned int            magic;          /*%< Magic number. */
        unsigned int            allowed;        /*%< Allowed methods. */
-       isc_boolean_t           enabled;        /*%< If the compression is enabled at all. */
        int                     edns;           /*%< Edns version or -1. */
        /*% Global compression table. */
        dns_compressnode_t      *table[DNS_COMPRESS_TABLESIZE];