From 11721fb29b88d633c7b26e62ceb17a68ff4a870d Mon Sep 17 00:00:00 2001
From: "Peter (Stig) Edwards" <thatsafunnyname@gmail.com>
Date: Thu, 11 Jan 2024 13:52:18 +0000
Subject: [PATCH 1/2] Increase connection.wbuf size from 64k to 1m

This is to support setting keys with value_size 1047552 (1023k) as done in conf/set_big_values.

https://github.com/memcached/mc-crusher/issues/10
---
 mc-crusher.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/mc-crusher.c b/mc-crusher.c
index b4a13d0..d6cdd43 100644
--- a/mc-crusher.c
+++ b/mc-crusher.c
@@ -53,6 +53,8 @@
 
 #define SHARED_RBUF_SIZE 1024 * 64
 #define SHARED_VALUE_SIZE 1024 * 1024
+// Big enough for conf/set_big_values and below valgrind max-stackframe
+#define WBUF_SIZE 1024 * 1024
 // avoiding some hacks for finding member size.
 #define SOCK_MAX 100
 
@@ -152,7 +154,7 @@ struct connection {
     int (*ascii_format)(struct connection *c);
     int (*bin_format)(struct connection *c);
     int (*bin_prep_cmd)(struct connection *c);
-    unsigned char wbuf[65536]; // putting this at the end to get more of the above into fewer cachelines.
+    unsigned char wbuf[WBUF_SIZE]; // putting this at the end to get more of the above into fewer cachelines.
 };
 
 static void client_handler(const int fd, const short which, void *arg);
@@ -915,6 +917,13 @@ static void parse_config_line(mc_thread *main_thread, char *line, bool use_sock)
             break;
         case VALUE_SIZE:
             template.value_size = atoi(value);
+            if(template.value_size > WBUF_SIZE){
+                fprintf(stderr, "Error, value_size (%i) too large, WBUF_SIZE is %i\n", template.value_size, WBUF_SIZE);
+                exit(-1);
+            }
+            if( (template.value_size + 1024) > WBUF_SIZE){ // allow 1024 bytes for command, key and metadata
+                fprintf(stderr, "Warning, value_size (%i + 1024) may be too large, WBUF_SIZE is %i\n", template.value_size, WBUF_SIZE);
+            }
             break;
         case VALUE:
             strcpy(template.s->value, value);

From 616d999e56d7b80b6e9c8dc88c3a1b1fc2a1febf Mon Sep 17 00:00:00 2001
From: "Peter (Stig) Edwards" <thatsafunnyname@gmail.com>
Date: Fri, 12 Jan 2024 12:26:19 +0000
Subject: [PATCH 2/2] Support value_size > 64k

connection.wbuf is changed from a static sized array on the stack to a pointer to a dynamically sized heap allocation.
  So that configs with many connections do not over allocate memory for wbuf, while also now supporting value_size > 64k
---
 mc-crusher.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/mc-crusher.c b/mc-crusher.c
index d6cdd43..5214e6d 100644
--- a/mc-crusher.c
+++ b/mc-crusher.c
@@ -53,8 +53,7 @@
 
 #define SHARED_RBUF_SIZE 1024 * 64
 #define SHARED_VALUE_SIZE 1024 * 1024
-// Big enough for conf/set_big_values and below valgrind max-stackframe
-#define WBUF_SIZE 1024 * 1024
+#define MIN_WBUF_SIZE 65536
 // avoiding some hacks for finding member size.
 #define SOCK_MAX 100
 
@@ -154,7 +153,7 @@ struct connection {
     int (*ascii_format)(struct connection *c);
     int (*bin_format)(struct connection *c);
     int (*bin_prep_cmd)(struct connection *c);
-    unsigned char wbuf[WBUF_SIZE]; // putting this at the end to get more of the above into fewer cachelines.
+    unsigned char *wbuf;
 };
 
 static void client_handler(const int fd, const short which, void *arg);
@@ -546,7 +545,7 @@ static inline void run_write(struct connection *c) {
     }
     {
         // not using iovecs, save some libc/kernel looping.
-        c->wbuf_towrite = c->wbuf_pos - (unsigned char *)&c->wbuf;
+        c->wbuf_towrite = c->wbuf_pos - c->wbuf;
         c->wbuf_written = 0;
         //fprintf(stderr, "WBUF towrite: %d\n", c->wbuf_towrite);
         write_flat(c, c->next_state);
@@ -917,13 +916,6 @@ static void parse_config_line(mc_thread *main_thread, char *line, bool use_sock)
             break;
         case VALUE_SIZE:
             template.value_size = atoi(value);
-            if(template.value_size > WBUF_SIZE){
-                fprintf(stderr, "Error, value_size (%i) too large, WBUF_SIZE is %i\n", template.value_size, WBUF_SIZE);
-                exit(-1);
-            }
-            if( (template.value_size + 1024) > WBUF_SIZE){ // allow 1024 bytes for command, key and metadata
-                fprintf(stderr, "Warning, value_size (%i + 1024) may be too large, WBUF_SIZE is %i\n", template.value_size, WBUF_SIZE);
-            }
             break;
         case VALUE:
             strcpy(template.s->value, value);
@@ -1049,6 +1041,13 @@ static void start_template(struct connection *template, int conns_tomake, bool u
     *template->cur_key = 0;
     *template->write_count = 0;
 
+    size_t wbuf_size = template->value_size + 1024; // space for op, key and metadata
+    if( wbuf_size < MIN_WBUF_SIZE ){
+        wbuf_size = MIN_WBUF_SIZE;
+    }
+    template->wbuf = (unsigned char*)malloc(wbuf_size);
+    memset(template->wbuf, 0, wbuf_size);
+
     int i, newsock;
     for (i = 0; i < conns_tomake; i++) {
         if (use_sock) {