MINOR: pool: move pool declarations to read_mostly

All pool heads are accessed via a pointer and should not be shared with
highly written variables. Move them to the read_mostly section.
diff --git a/src/chunk.c b/src/chunk.c
index ade0323..5c720c1 100644
--- a/src/chunk.c
+++ b/src/chunk.c
@@ -26,12 +26,12 @@
 static THREAD_LOCAL struct buffer trash_chunk2;
 
 /* trash buffers used for various conversions */
-static int trash_size;
+static int trash_size __read_mostly;
 static THREAD_LOCAL char *trash_buf1;
 static THREAD_LOCAL char *trash_buf2;
 
 /* the trash pool for reentrant allocations */
-struct pool_head *pool_head_trash = NULL;
+struct pool_head *pool_head_trash __read_mostly = NULL;
 
 /* this is used to drain data, and as a temporary buffer for sprintf()... */
 THREAD_LOCAL struct buffer trash = { };
diff --git a/src/compression.c b/src/compression.c
index da6213e..1d275ed 100644
--- a/src/compression.c
+++ b/src/compression.c
@@ -48,11 +48,11 @@
 static void free_zlib(void *opaque, void *ptr);
 
 /* zlib allocation  */
-static struct pool_head *zlib_pool_deflate_state = NULL;
-static struct pool_head *zlib_pool_window = NULL;
-static struct pool_head *zlib_pool_prev = NULL;
-static struct pool_head *zlib_pool_head = NULL;
-static struct pool_head *zlib_pool_pending_buf = NULL;
+static struct pool_head *zlib_pool_deflate_state __read_mostly = NULL;
+static struct pool_head *zlib_pool_window __read_mostly = NULL;
+static struct pool_head *zlib_pool_prev __read_mostly = NULL;
+static struct pool_head *zlib_pool_head __read_mostly = NULL;
+static struct pool_head *zlib_pool_pending_buf __read_mostly = NULL;
 
 long zlib_used_memory = 0;
 
diff --git a/src/dynbuf.c b/src/dynbuf.c
index 8b492e2..fcbb8fa 100644
--- a/src/dynbuf.c
+++ b/src/dynbuf.c
@@ -20,7 +20,7 @@
 #include <haproxy/list.h>
 #include <haproxy/pool.h>
 
-struct pool_head *pool_head_buffer;
+struct pool_head *pool_head_buffer __read_mostly;
 
 /* perform minimal intializations, report 0 in case of error, 1 if OK. */
 int init_buffer()
diff --git a/src/extcheck.c b/src/extcheck.c
index 79a63b2..808b4bb 100644
--- a/src/extcheck.c
+++ b/src/extcheck.c
@@ -43,7 +43,7 @@
 
 
 static struct list pid_list = LIST_HEAD_INIT(pid_list);
-static struct pool_head *pool_head_pid_list;
+static struct pool_head *pool_head_pid_list __read_mostly;
 __decl_spinlock(pid_list_lock);
 
 struct extcheck_env {
diff --git a/src/hpack-tbl.c b/src/hpack-tbl.c
index da81d29..8df1031 100644
--- a/src/hpack-tbl.c
+++ b/src/hpack-tbl.c
@@ -99,7 +99,7 @@
 	[61] = { .n = IST("www-authenticate"),             .v = IST("")              },
 };
 
-struct pool_head *pool_head_hpack_tbl = NULL;
+struct pool_head *pool_head_hpack_tbl __read_mostly = NULL;
 
 #ifdef DEBUG_HPACK
 /* dump the whole dynamic header table */
diff --git a/src/http_ana.c b/src/http_ana.c
index f49d07f..0a32107 100644
--- a/src/http_ana.c
+++ b/src/http_ana.c
@@ -42,8 +42,8 @@
 
 extern const char *stat_status_codes[];
 
-struct pool_head *pool_head_requri = NULL;
-struct pool_head *pool_head_capture = NULL;
+struct pool_head *pool_head_requri __read_mostly = NULL;
+struct pool_head *pool_head_capture __read_mostly = NULL;
 
 
 static void http_end_request(struct stream *s);
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index f1b0668..d3e5931 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -482,14 +482,14 @@
 	return ca_e->ca_list;
 }
 
-struct pool_head *pool_head_ssl_capture = NULL;
+struct pool_head *pool_head_ssl_capture __read_mostly = NULL;
 int ssl_capture_ptr_index = -1;
 int ssl_app_data_index = -1;
 
 #ifdef HAVE_OPENSSL_KEYLOG
 int ssl_keylog_index = -1;
-struct pool_head *pool_head_ssl_keylog = NULL;
-struct pool_head *pool_head_ssl_keylog_str = NULL;
+struct pool_head *pool_head_ssl_keylog __read_mostly = NULL;
+struct pool_head *pool_head_ssl_keylog_str __read_mostly = NULL;
 #endif
 
 #if (defined SSL_CTRL_SET_TLSEXT_TICKET_KEY_CB && TLS_TICKETS_NO > 0)