diff --git a/client/CMakeLists.txt b/client/CMakeLists.txt
index 55fd02b23c3..4dfce2478cd 100644
--- a/client/CMakeLists.txt
+++ b/client/CMakeLists.txt
@@ -16,7 +16,7 @@
 
 INCLUDE_DIRECTORIES(
   ${CMAKE_SOURCE_DIR}/include
-  ${PCRE_INCLUDES}
+  ${PCRE_INCLUDE_DIRS}
   ${CMAKE_SOURCE_DIR}/mysys_ssl
   ${ZLIB_INCLUDE_DIR}
   ${SSL_INCLUDE_DIRS}
diff --git a/cmake/os/AIX.cmake b/cmake/os/AIX.cmake
index 299b79198c6..7513c4f42c2 100644
--- a/cmake/os/AIX.cmake
+++ b/cmake/os/AIX.cmake
@@ -34,5 +34,8 @@ ELSE()
   SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGE_FILES -maix64 -pthread -mcmodel=large")
 ENDIF()
 
+# fcntl(fd, F_SETFL, O_DIRECT) is not supported; O_DIRECT is an open(2) flag
+SET(HAVE_FCNTL_DIRECT 0 CACHE INTERNAL "")
+
 # make it WARN by default, not AUTO (that implies -Werror)
 SET(MYSQL_MAINTAINER_MODE "WARN" CACHE STRING "Enable MariaDB maintainer-specific warnings. One of: NO (warnings are disabled) WARN (warnings are enabled) ERR (warnings are errors) AUTO (warnings are errors in Debug only)")
diff --git a/cmake/os/SunOS.cmake b/cmake/os/SunOS.cmake
index 3a9d2dccb87..3d99d34789a 100644
--- a/cmake/os/SunOS.cmake
+++ b/cmake/os/SunOS.cmake
@@ -17,6 +17,10 @@ INCLUDE(CheckSymbolExists)
 INCLUDE(CheckCSourceRuns)
 INCLUDE(CheckCSourceCompiles) 
 
+# fcntl(fd, F_SETFL, O_DIRECT) is not supported,
+# and directio(3C) would only work on UFS or NFS, not ZFS.
+SET(HAVE_FCNTL_DIRECT 0 CACHE INTERNAL "")
+
 # Enable 64 bit file offsets
 SET(_FILE_OFFSET_BITS 64)
 
diff --git a/cmake/os/WindowsCache.cmake b/cmake/os/WindowsCache.cmake
index c1048661aaa..ceb4262730f 100644
--- a/cmake/os/WindowsCache.cmake
+++ b/cmake/os/WindowsCache.cmake
@@ -44,6 +44,7 @@ SET(HAVE_EXECINFO_H CACHE  INTERNAL "")
 SET(HAVE_FCHMOD CACHE  INTERNAL "")
 SET(HAVE_FCNTL CACHE  INTERNAL "")
 SET(HAVE_FCNTL_H 1 CACHE  INTERNAL "")
+SET(HAVE_FCNTL_DIRECT 0 CACHE  INTERNAL "")
 SET(HAVE_FCNTL_NONBLOCK CACHE  INTERNAL "")
 SET(HAVE_FDATASYNC CACHE  INTERNAL "")
 SET(HAVE_DECL_FDATASYNC CACHE INTERNAL "")
diff --git a/cmake/pcre.cmake b/cmake/pcre.cmake
index 65dc2ae28f6..c2eb26074ac 100644
--- a/cmake/pcre.cmake
+++ b/cmake/pcre.cmake
@@ -1,4 +1,3 @@
-INCLUDE (CheckCSourceRuns)
 INCLUDE (ExternalProject)
 
 SET(WITH_PCRE "auto" CACHE STRING
@@ -6,7 +5,8 @@ SET(WITH_PCRE "auto" CACHE STRING
 
 MACRO(BUNDLE_PCRE2)
   SET(dir "${CMAKE_BINARY_DIR}/extra/pcre2")
-  SET(PCRE_INCLUDES ${dir}/src/pcre2-build ${dir}/src/pcre2/src)
+  SET(PCRE_INCLUDE_DIRS ${dir}/src/pcre2-build ${dir}/src/pcre2/src)
+  MESSAGE(STATUS "Will download and bundle pcre2")
   SET(byproducts)
   FOREACH(lib pcre2-posix pcre2-8)
     ADD_LIBRARY(${lib} STATIC IMPORTED GLOBAL)
@@ -76,18 +76,26 @@ SET_TARGET_PROPERTIES(pcre2 PROPERTIES EXCLUDE_FROM_ALL TRUE)
 ENDMACRO()
 
 MACRO (CHECK_PCRE)
-  IF(WITH_PCRE STREQUAL "system" OR WITH_PCRE STREQUAL "auto")
-    CHECK_LIBRARY_EXISTS(pcre2-8 pcre2_match_8 "" HAVE_PCRE2)
-  ENDIF()
-  IF(NOT HAVE_PCRE2 OR WITH_PCRE STREQUAL "bundled")
-    IF (WITH_PCRE STREQUAL "system")
-      MESSAGE(FATAL_ERROR "system pcre2-8 library is not found or unusable")
+  IF (NOT TARGET pcre2 AND NOT PCRE_FOUND)
+    IF(WITH_PCRE STREQUAL "system" OR WITH_PCRE STREQUAL "auto")
+      FIND_PACKAGE(PkgConfig QUIET)
+      PKG_CHECK_MODULES(PCRE libpcre2-8)
+      # in case pkg-config or libpcre2-8.pc is not installed:
+      IF(NOT PCRE_FOUND)
+        UNSET(PCRE_FOUND CACHE)
+        CHECK_LIBRARY_EXISTS(pcre2-8 pcre2_match_8 "" PCRE_FOUND)
+      ENDIF()
     ENDIF()
-    BUNDLE_PCRE2()
-  ELSE()
-    CHECK_LIBRARY_EXISTS(pcre2-posix PCRE2regcomp "" NEEDS_PCRE2_DEBIAN_HACK)
-    IF(NEEDS_PCRE2_DEBIAN_HACK)
-      SET(PCRE2_DEBIAN_HACK "-Dregcomp=PCRE2regcomp -Dregexec=PCRE2regexec -Dregerror=PCRE2regerror -Dregfree=PCRE2regfree")
+    IF(NOT PCRE_FOUND OR WITH_PCRE STREQUAL "bundled")
+      IF (WITH_PCRE STREQUAL "system")
+        MESSAGE(FATAL_ERROR "system pcre2-8 library is not found or unusable")
+      ENDIF()
+      BUNDLE_PCRE2()
+    ELSE()
+      CHECK_LIBRARY_EXISTS(pcre2-posix PCRE2regcomp "" NEEDS_PCRE2_DEBIAN_HACK)
+      IF(NEEDS_PCRE2_DEBIAN_HACK)
+        SET(PCRE2_DEBIAN_HACK "-Dregcomp=PCRE2regcomp -Dregexec=PCRE2regexec -Dregerror=PCRE2regerror -Dregfree=PCRE2regfree")
+      ENDIF()
     ENDIF()
   ENDIF()
 ENDMACRO()
diff --git a/cmake/plugin.cmake b/cmake/plugin.cmake
index 813d8ef6e42..6efd40fd1bd 100644
--- a/cmake/plugin.cmake
+++ b/cmake/plugin.cmake
@@ -44,7 +44,7 @@ MACRO(MYSQL_ADD_PLUGIN)
   # Add common include directories
   INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/include 
                     ${CMAKE_SOURCE_DIR}/sql
-                    ${PCRE_INCLUDES}
+                    ${PCRE_INCLUDE_DIRS}
                     ${SSL_INCLUDE_DIRS}
                     ${ZLIB_INCLUDE_DIR})
 
diff --git a/config.h.cmake b/config.h.cmake
index 733c407af8e..47a87c201d4 100644
--- a/config.h.cmake
+++ b/config.h.cmake
@@ -30,6 +30,7 @@
 #cmakedefine HAVE_DLFCN_H 1
 #cmakedefine HAVE_EXECINFO_H 1
 #cmakedefine HAVE_FCNTL_H 1
+#cmakedefine HAVE_FCNTL_DIRECT 1
 #cmakedefine HAVE_FENV_H 1
 #cmakedefine HAVE_FLOAT_H 1
 #cmakedefine HAVE_FNMATCH_H 1
diff --git a/configure.cmake b/configure.cmake
index c2706b50502..061837c1226 100644
--- a/configure.cmake
+++ b/configure.cmake
@@ -706,6 +706,7 @@ CHECK_SYMBOL_EXISTS(O_NONBLOCK "unistd.h;fcntl.h" HAVE_FCNTL_NONBLOCK)
 IF(NOT HAVE_FCNTL_NONBLOCK)
  SET(NO_FCNTL_NONBLOCK 1)
 ENDIF()
+CHECK_SYMBOL_EXISTS(O_DIRECT "fcntl.h" HAVE_FCNTL_DIRECT)
 
 #
 # Test for how the C compiler does inline, if at all
diff --git a/extra/mariabackup/CMakeLists.txt b/extra/mariabackup/CMakeLists.txt
index 66293dac31b..f1c9dca7561 100644
--- a/extra/mariabackup/CMakeLists.txt
+++ b/extra/mariabackup/CMakeLists.txt
@@ -36,7 +36,7 @@ INCLUDE_DIRECTORIES(
   )
 
 IF(NOT HAVE_SYSTEM_REGEX)
-  INCLUDE_DIRECTORIES(${PCRE_INCLUDES})
+  INCLUDE_DIRECTORIES(${PCRE_INCLUDE_DIRS})
   ADD_DEFINITIONS(${PCRE2_DEBIAN_HACK})
 ENDIF()
 
diff --git a/extra/mariabackup/fil_cur.cc b/extra/mariabackup/fil_cur.cc
index e0a4711a2aa..4f5d67a5853 100644
--- a/extra/mariabackup/fil_cur.cc
+++ b/extra/mariabackup/fil_cur.cc
@@ -199,11 +199,13 @@ xb_fil_cur_open(
 		return(XB_FIL_CUR_SKIP);
 	}
 
+#ifdef HAVE_FCNTL_DIRECT
 	if (srv_file_flush_method == SRV_O_DIRECT
 	    || srv_file_flush_method == SRV_O_DIRECT_NO_FSYNC) {
 
 		os_file_set_nocache(cursor->file, node->name, "OPEN");
 	}
+#endif
 
 	posix_fadvise(cursor->file, 0, 0, POSIX_FADV_SEQUENTIAL);
 
diff --git a/libmariadb b/libmariadb
index 458a4396b44..26cef16b25f 160000
--- a/libmariadb
+++ b/libmariadb
@@ -1 +1 @@
-Subproject commit 458a4396b443dcefedcf464067560078aa09d8b4
+Subproject commit 26cef16b25f01c1b159b0c73e3f6d9bcfcac90d5
diff --git a/libmysqld/CMakeLists.txt b/libmysqld/CMakeLists.txt
index 04cc2159b87..63cdd03e368 100644
--- a/libmysqld/CMakeLists.txt
+++ b/libmysqld/CMakeLists.txt
@@ -23,7 +23,7 @@ ${CMAKE_SOURCE_DIR}/libmysqld
 ${CMAKE_SOURCE_DIR}/sql
 ${CMAKE_SOURCE_DIR}/tpool
 ${CMAKE_BINARY_DIR}/sql 
-${PCRE_INCLUDES}
+${PCRE_INCLUDE_DIRS}
 ${LIBFMT_INCLUDE_DIR}
 ${ZLIB_INCLUDE_DIR}
 ${SSL_INCLUDE_DIRS}
diff --git a/libmysqld/examples/CMakeLists.txt b/libmysqld/examples/CMakeLists.txt
index 2a10def8e2e..d6646a128ca 100644
--- a/libmysqld/examples/CMakeLists.txt
+++ b/libmysqld/examples/CMakeLists.txt
@@ -15,7 +15,7 @@
 
 INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/include
                     ${CMAKE_SOURCE_DIR}/libmysqld/include
-                    ${PCRE_INCLUDES}
+                    ${PCRE_INCLUDE_DIRS}
                     ${CMAKE_SOURCE_DIR}/sql
                     ${MY_READLINE_INCLUDE_DIR}
                     )
diff --git a/mysql-test/mariadb-test-run.pl b/mysql-test/mariadb-test-run.pl
index 1e868efa0b1..0853b6b1143 100755
--- a/mysql-test/mariadb-test-run.pl
+++ b/mysql-test/mariadb-test-run.pl
@@ -4506,7 +4506,7 @@ sub extract_warning_lines ($$) {
      qr|InnoDB: io_setup\(\) failed with EAGAIN|,
      qr|io_uring_queue_init\(\) failed with|,
      qr|InnoDB: liburing disabled|,
-     qr/InnoDB: Failed to set (O_DIRECT|DIRECTIO_ON) on file/,
+     qr/InnoDB: Failed to set O_DIRECT on file/,
      qr|setrlimit could not change the size of core files to 'infinity';|,
      qr|feedback plugin: failed to retrieve the MAC address|,
      qr|Plugin 'FEEDBACK' init function returned error|,
diff --git a/mysql-test/suite/innodb/t/doublewrite.test b/mysql-test/suite/innodb/t/doublewrite.test
index 541e4d23a19..7e38851facb 100644
--- a/mysql-test/suite/innodb/t/doublewrite.test
+++ b/mysql-test/suite/innodb/t/doublewrite.test
@@ -39,6 +39,9 @@ commit work;
 SET GLOBAL innodb_fast_shutdown = 0;
 let $shutdown_timeout=;
 --source include/restart_mysqld.inc
+# Ensure that buf_flush_page_cleaner() has woken up from its
+# first my_cond_timedwait() and gone idle.
+sleep 1;
 --source ../include/no_checkpoint_start.inc
 connect (dml,localhost,root,,);
 XA START 'x';
diff --git a/mysql-test/suite/perfschema/r/sxlock_func,debug.rdiff b/mysql-test/suite/perfschema/r/sxlock_func,debug.rdiff
deleted file mode 100644
index 0596810e553..00000000000
--- a/mysql-test/suite/perfschema/r/sxlock_func,debug.rdiff
+++ /dev/null
@@ -1,22 +0,0 @@
-@@ -7,7 +7,6 @@
- WHERE name LIKE 'wait/synch/rwlock/innodb/%'
- AND name!='wait/synch/rwlock/innodb/btr_search_latch' ORDER BY name;
- name
--wait/synch/rwlock/innodb/dict_operation_lock
- wait/synch/rwlock/innodb/fil_space_latch
- wait/synch/rwlock/innodb/lock_latch
- wait/synch/rwlock/innodb/trx_i_s_cache_lock
-@@ -19,11 +18,13 @@
- select name from performance_schema.setup_instruments
- where name like "wait/synch/sxlock/%" order by name;
- name
-+wait/synch/sxlock/innodb/dict_operation_lock
- wait/synch/sxlock/innodb/index_tree_rw_lock
- SELECT DISTINCT name FROM performance_schema.rwlock_instances
- WHERE name LIKE 'wait/synch/sxlock/innodb/%'
- ORDER BY name;
- name
-+wait/synch/sxlock/innodb/dict_operation_lock
- wait/synch/sxlock/innodb/index_tree_rw_lock
- create table t1(a int) engine=innodb;
- begin;
diff --git a/mysql-test/suite/perfschema/t/sxlock_func.test b/mysql-test/suite/perfschema/t/sxlock_func.test
index 24d0e07ca41..c43adc849d2 100644
--- a/mysql-test/suite/perfschema/t/sxlock_func.test
+++ b/mysql-test/suite/perfschema/t/sxlock_func.test
@@ -5,7 +5,6 @@
 --source include/not_embedded.inc
 --source include/have_perfschema.inc
 --source include/have_innodb.inc
---source include/maybe_debug.inc
 
 UPDATE performance_schema.setup_instruments SET enabled = 'NO', timed = 'YES';
 
diff --git a/plugin/feedback/CMakeLists.txt b/plugin/feedback/CMakeLists.txt
index 2103250e5a6..fc35cbadc31 100644
--- a/plugin/feedback/CMakeLists.txt
+++ b/plugin/feedback/CMakeLists.txt
@@ -1,5 +1,5 @@
 INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/sql
-                    ${PCRE_INCLUDES}
+                    ${PCRE_INCLUDE_DIRS}
                     ${SSL_INCLUDE_DIRS})
 
 SET(FEEDBACK_SOURCES feedback.cc sender_thread.cc
diff --git a/plugin/qc_info/CMakeLists.txt b/plugin/qc_info/CMakeLists.txt
index b8c5f926cff..329f49c1fc9 100644
--- a/plugin/qc_info/CMakeLists.txt
+++ b/plugin/qc_info/CMakeLists.txt
@@ -1,4 +1,4 @@
 INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/sql
-                    ${PCRE_INCLUDES})
+                    ${PCRE_INCLUDE_DIRS})
 
 MYSQL_ADD_PLUGIN(QUERY_CACHE_INFO qc_info.cc RECOMPILE_FOR_EMBEDDED)
diff --git a/scripts/mysql_install_db.sh b/scripts/mysql_install_db.sh
index 31557b60d5d..742eb1e17cf 100644
--- a/scripts/mysql_install_db.sh
+++ b/scripts/mysql_install_db.sh
@@ -695,7 +695,7 @@ then
   then
     echo
     echo "You can start the MariaDB daemon with:"
-    echo "cd '$basedir' ; $bindir/mariadb-safe --datadir='$ldata'"
+    echo "cd '$basedir' ; $bindir/mariadbd-safe --datadir='$ldata'"
     echo
     echo "You can test the MariaDB daemon with mysql-test-run.pl"
     echo "cd '$basedir/@INSTALL_MYSQLTESTDIR@' ; perl mariadb-test-run.pl"
diff --git a/sql/CMakeLists.txt b/sql/CMakeLists.txt
index 13d9d02cef5..8d8cec7f6a3 100644
--- a/sql/CMakeLists.txt
+++ b/sql/CMakeLists.txt
@@ -55,7 +55,7 @@ INCLUDE_DIRECTORIES(
 ${CMAKE_SOURCE_DIR}/include
 ${CMAKE_SOURCE_DIR}/sql
 ${LIBFMT_INCLUDE_DIR}
-${PCRE_INCLUDES}
+${PCRE_INCLUDE_DIRS}
 ${ZLIB_INCLUDE_DIR}
 ${SSL_INCLUDE_DIRS}
 ${CMAKE_BINARY_DIR}/sql
diff --git a/storage/innobase/buf/buf0dump.cc b/storage/innobase/buf/buf0dump.cc
index 769929642cd..cc51f8c6573 100644
--- a/storage/innobase/buf/buf0dump.cc
+++ b/storage/innobase/buf/buf0dump.cc
@@ -180,7 +180,7 @@ static void buf_dump_generate_path(char *path, size_t path_size)
 	char	buf[FN_REFLEN];
 
 	mysql_mutex_lock(&LOCK_global_system_variables);
-	snprintf(buf, sizeof buf, "%s/%s", get_buf_dump_dir(),
+	snprintf(buf, sizeof buf, "%s" FN_ROOTDIR "%s", get_buf_dump_dir(),
 		 srv_buf_dump_filename);
 	mysql_mutex_unlock(&LOCK_global_system_variables);
 
@@ -214,7 +214,7 @@ static void buf_dump_generate_path(char *path, size_t path_size)
 			format = "%s%s";
 			break;
 		default:
-			format = "%s/%s";
+			format = "%s" FN_ROOTDIR "%s";
 		}
 
 		snprintf(path, path_size, format,
diff --git a/storage/innobase/buf/buf0flu.cc b/storage/innobase/buf/buf0flu.cc
index 7df8db8da79..d4628985c1a 100644
--- a/storage/innobase/buf/buf0flu.cc
+++ b/storage/innobase/buf/buf0flu.cc
@@ -1759,6 +1759,28 @@ ulint buf_flush_LRU(ulint max_n, bool evict)
     buf_pool.try_LRU_scan= true;
     pthread_cond_broadcast(&buf_pool.done_free);
   }
+  else if (!pages && !buf_pool.try_LRU_scan &&
+           !buf_pool.LRU_warned.test_and_set(std::memory_order_acquire))
+  {
+    /* For example, with the minimum innodb_buffer_pool_size=5M and
+    the default innodb_page_size=16k there are only a little over 316
+    pages in the buffer pool. The buffer pool can easily be exhausted
+    by a workload of some dozen concurrent connections. The system could
+    reach a deadlock like the following:
+
+    (1) Many threads are waiting in buf_LRU_get_free_block()
+    for buf_pool.done_free.
+    (2) Some threads are waiting for a page latch which is held by
+    another thread that is waiting in buf_LRU_get_free_block().
+    (3) This thread is the only one that could make progress, but
+    we fail to do so because all the pages that we scanned are
+    buffer-fixed or latched by some thread. */
+    sql_print_warning("InnoDB: Could not free any blocks in the buffer pool!"
+                      " %zu blocks are in use and %zu free."
+                      " Consider increasing innodb_buffer_pool_size.",
+                      UT_LIST_GET_LEN(buf_pool.LRU),
+                      UT_LIST_GET_LEN(buf_pool.free));
+  }
 
   return pages;
 }
@@ -2391,11 +2413,19 @@ func_exit:
 	goto func_exit;
 }
 
+TPOOL_SUPPRESS_TSAN
+bool buf_pool_t::need_LRU_eviction() const
+{
+  /* try_LRU_scan==false means that buf_LRU_get_free_block() is waiting
+  for buf_flush_page_cleaner() to evict some blocks */
+  return UNIV_UNLIKELY(!try_LRU_scan ||
+                       (UT_LIST_GET_LEN(LRU) > BUF_LRU_MIN_LEN &&
+                        UT_LIST_GET_LEN(free) < srv_LRU_scan_depth / 2));
+}
+
 #if defined __aarch64__&&defined __GNUC__&&__GNUC__==4&&!defined __clang__
-/* Avoid GCC 4.8.5 internal compiler error "could not split insn".
-We would only need this for buf_flush_page_cleaner(),
-but GCC 4.8.5 does not support pop_options. */
-# pragma GCC optimize ("O0")
+/* Avoid GCC 4.8.5 internal compiler error "could not split insn". */
+__attribute__((optimize(0)))
 #endif
 /** page_cleaner thread tasked with flushing dirty pages from the buffer
 pools. As of now we'll have only one coordinator. */
@@ -2429,21 +2459,24 @@ static void buf_flush_page_cleaner()
     }
 
     mysql_mutex_lock(&buf_pool.flush_list_mutex);
-    if (buf_pool.ran_out())
-      goto no_wait;
-    else if (srv_shutdown_state > SRV_SHUTDOWN_INITIATED)
-      break;
+    if (!buf_pool.need_LRU_eviction())
+    {
+      if (srv_shutdown_state > SRV_SHUTDOWN_INITIATED)
+        break;
 
-    if (buf_pool.page_cleaner_idle() &&
-        (!UT_LIST_GET_LEN(buf_pool.flush_list) ||
-         srv_max_dirty_pages_pct_lwm == 0.0))
-      /* We are idle; wait for buf_pool.page_cleaner_wakeup() */
-      my_cond_wait(&buf_pool.do_flush_list,
-                   &buf_pool.flush_list_mutex.m_mutex);
-    else
-      my_cond_timedwait(&buf_pool.do_flush_list,
-                        &buf_pool.flush_list_mutex.m_mutex, &abstime);
-  no_wait:
+      if (buf_pool.page_cleaner_idle() &&
+          (!UT_LIST_GET_LEN(buf_pool.flush_list) ||
+           srv_max_dirty_pages_pct_lwm == 0.0))
+      {
+        buf_pool.LRU_warned.clear(std::memory_order_release);
+        /* We are idle; wait for buf_pool.page_cleaner_wakeup() */
+        my_cond_wait(&buf_pool.do_flush_list,
+                     &buf_pool.flush_list_mutex.m_mutex);
+      }
+      else
+        my_cond_timedwait(&buf_pool.do_flush_list,
+                          &buf_pool.flush_list_mutex.m_mutex, &abstime);
+    }
     set_timespec(abstime, 1);
 
     lsn_limit= buf_flush_sync_lsn;
@@ -2475,7 +2508,7 @@ static void buf_flush_page_cleaner()
       }
       while (false);
 
-      if (!buf_pool.ran_out())
+      if (!buf_pool.need_LRU_eviction())
         continue;
       mysql_mutex_lock(&buf_pool.flush_list_mutex);
       oldest_lsn= buf_pool.get_oldest_modification(0);
@@ -2504,7 +2537,7 @@ static void buf_flush_page_cleaner()
       if (oldest_lsn >= soft_lsn_limit)
         buf_flush_async_lsn= soft_lsn_limit= 0;
     }
-    else if (buf_pool.ran_out())
+    else if (buf_pool.need_LRU_eviction())
     {
       buf_pool.page_cleaner_set_idle(false);
       buf_pool.n_flush_inc();
@@ -2619,9 +2652,13 @@ static void buf_flush_page_cleaner()
                                    MONITOR_FLUSH_ADAPTIVE_PAGES,
                                    n_flushed);
     }
-    else if (buf_flush_async_lsn <= oldest_lsn)
+    else if (buf_flush_async_lsn <= oldest_lsn &&
+             !buf_pool.need_LRU_eviction())
       goto check_oldest_and_set_idle;
+    else
+      mysql_mutex_lock(&buf_pool.mutex);
 
+    n= srv_max_io_capacity;
     n= n >= n_flushed ? n - n_flushed : 0;
     goto LRU_flush;
   }
diff --git a/storage/innobase/buf/buf0lru.cc b/storage/innobase/buf/buf0lru.cc
index 662dacc8f13..2a8d6ff23b9 100644
--- a/storage/innobase/buf/buf0lru.cc
+++ b/storage/innobase/buf/buf0lru.cc
@@ -60,10 +60,6 @@ static constexpr ulint BUF_LRU_OLD_TOLERANCE = 20;
 frames in the buffer pool, we set this to TRUE */
 static bool buf_lru_switched_on_innodb_mon = false;
 
-/** True if diagnostic message about difficult to find free blocks
-in the buffer bool has already printed. */
-static bool	buf_lru_free_blocks_error_printed;
-
 /******************************************************************//**
 These statistics are not 'of' LRU but 'for' LRU.  We keep count of I/O
 and page_zip_decompress() operations.  Based on the statistics,
@@ -408,6 +404,7 @@ got_mutex:
 	buf_LRU_check_size_of_non_data_objects();
 	buf_block_t* block;
 
+	IF_DBUG(static bool buf_lru_free_blocks_error_printed,);
 	DBUG_EXECUTE_IF("ib_lru_force_no_free_page",
 		if (!buf_lru_free_blocks_error_printed) {
 			n_iterations = 21;
@@ -417,9 +414,25 @@ retry:
 	/* If there is a block in the free list, take it */
 	if ((block = buf_LRU_get_free_only()) != nullptr) {
 got_block:
+		const ulint LRU_size = UT_LIST_GET_LEN(buf_pool.LRU);
+		const ulint available = UT_LIST_GET_LEN(buf_pool.free);
+		const ulint scan_depth = srv_LRU_scan_depth / 2;
+		ut_ad(LRU_size <= BUF_LRU_MIN_LEN || available >= scan_depth
+		      || buf_pool.need_LRU_eviction());
+
 		if (!have_mutex) {
 			mysql_mutex_unlock(&buf_pool.mutex);
 		}
+
+		if (UNIV_UNLIKELY(available < scan_depth)
+		    && LRU_size > BUF_LRU_MIN_LEN) {
+			mysql_mutex_lock(&buf_pool.flush_list_mutex);
+			if (!buf_pool.page_cleaner_active()) {
+				buf_pool.page_cleaner_wakeup(true);
+			}
+			mysql_mutex_unlock(&buf_pool.flush_list_mutex);
+		}
+
 		block->page.zip.clear();
 		return block;
 	}
@@ -445,10 +458,11 @@ got_block:
 		if ((block = buf_LRU_get_free_only()) != nullptr) {
 			goto got_block;
 		}
+		const bool wake = buf_pool.need_LRU_eviction();
 		mysql_mutex_unlock(&buf_pool.mutex);
 		mysql_mutex_lock(&buf_pool.flush_list_mutex);
 		const auto n_flush = buf_pool.n_flush();
-		if (!buf_pool.try_LRU_scan) {
+		if (wake && !buf_pool.page_cleaner_active()) {
 			buf_pool.page_cleaner_wakeup(true);
 		}
 		mysql_mutex_unlock(&buf_pool.flush_list_mutex);
@@ -467,9 +481,10 @@ not_found:
 		MONITOR_INC( MONITOR_LRU_GET_FREE_WAITS );
 	}
 
-	if (n_iterations == 21 && !buf_lru_free_blocks_error_printed
-	    && srv_buf_pool_old_size == srv_buf_pool_size) {
-		buf_lru_free_blocks_error_printed = true;
+	if (n_iterations == 21
+	    && srv_buf_pool_old_size == srv_buf_pool_size
+	    && buf_pool.LRU_warned.test_and_set(std::memory_order_acquire)) {
+		IF_DBUG(buf_lru_free_blocks_error_printed = true,);
 		mysql_mutex_unlock(&buf_pool.mutex);
 		ib::warn() << "Difficult to find free blocks in the buffer pool"
 			" (" << n_iterations << " search iterations)! "
diff --git a/storage/innobase/dict/dict0dict.cc b/storage/innobase/dict/dict0dict.cc
index dfc41fcc7d5..5d3cab17ae1 100644
--- a/storage/innobase/dict/dict0dict.cc
+++ b/storage/innobase/dict/dict0dict.cc
@@ -958,12 +958,11 @@ void dict_sys_t::lock_wait(SRW_LOCK_ARGS(const char *file, unsigned line))
   if (latch_ex_wait_start.compare_exchange_strong
       (old, now, std::memory_order_relaxed, std::memory_order_relaxed))
   {
-#ifdef UNIV_DEBUG
-    latch.x_lock(SRW_LOCK_ARGS(file, line));
-#else
     latch.wr_lock(SRW_LOCK_ARGS(file, line));
-#endif
     latch_ex_wait_start.store(0, std::memory_order_relaxed);
+    ut_ad(!latch_readers);
+    ut_ad(!latch_ex);
+    ut_d(latch_ex= pthread_self());
     return;
   }
 
@@ -978,39 +977,33 @@ void dict_sys_t::lock_wait(SRW_LOCK_ARGS(const char *file, unsigned line))
   if (waited > threshold / 4)
     ib::warn() << "A long wait (" << waited
                << " seconds) was observed for dict_sys.latch";
-#ifdef UNIV_DEBUG
-  latch.x_lock(SRW_LOCK_ARGS(file, line));
-#else
   latch.wr_lock(SRW_LOCK_ARGS(file, line));
-#endif
+  ut_ad(!latch_readers);
+  ut_ad(!latch_ex);
+  ut_d(latch_ex= pthread_self());
 }
 
 #ifdef UNIV_PFS_RWLOCK
 ATTRIBUTE_NOINLINE void dict_sys_t::unlock()
 {
-# ifdef UNIV_DEBUG
-  latch.x_unlock();
-# else
+  ut_ad(latch_ex == pthread_self());
+  ut_ad(!latch_readers);
+  ut_d(latch_ex= 0);
   latch.wr_unlock();
-# endif
 }
 
 ATTRIBUTE_NOINLINE void dict_sys_t::freeze(const char *file, unsigned line)
 {
-# ifdef UNIV_DEBUG
-  latch.s_lock(file, line);
-# else
   latch.rd_lock(file, line);
-# endif
+  ut_ad(!latch_ex);
+  ut_d(latch_readers++);
 }
 
 ATTRIBUTE_NOINLINE void dict_sys_t::unfreeze()
 {
-# ifdef UNIV_DEBUG
-  latch.s_unlock();
-# else
+  ut_ad(!latch_ex);
+  ut_ad(latch_readers--);
   latch.rd_unlock();
-# endif
 }
 #endif /* UNIV_PFS_RWLOCK */
 
@@ -4550,11 +4543,7 @@ void dict_sys_t::close()
   temp_id_hash.free();
 
   unlock();
-#ifdef UNIV_DEBUG
-  latch.free();
-#else
   latch.destroy();
-#endif
 
   mysql_mutex_destroy(&dict_foreign_err_mutex);
 
diff --git a/storage/innobase/fil/fil0fil.cc b/storage/innobase/fil/fil0fil.cc
index 89d466a68f0..bd0ace7c429 100644
--- a/storage/innobase/fil/fil0fil.cc
+++ b/storage/innobase/fil/fil0fil.cc
@@ -341,8 +341,9 @@ static bool fil_node_open_file_low(fil_node_t *node)
   ut_ad(!node->is_open());
   ut_ad(node->space->is_closing());
   mysql_mutex_assert_owner(&fil_system.mutex);
-  ulint type;
   static_assert(((UNIV_ZIP_SIZE_MIN >> 1) << 3) == 4096, "compatibility");
+#if defined _WIN32 || defined HAVE_FCNTL_DIRECT
+  ulint type;
   switch (FSP_FLAGS_GET_ZIP_SSIZE(node->space->flags)) {
   case 1:
   case 2:
@@ -351,6 +352,9 @@ static bool fil_node_open_file_low(fil_node_t *node)
   default:
     type= OS_DATA_FILE;
   }
+#else
+  constexpr auto type= OS_DATA_FILE;
+#endif
 
   for (;;)
   {
@@ -1900,9 +1904,10 @@ fil_ibd_create(
 	mtr.flag_wr_unlock();
 	log_write_up_to(lsn, true);
 
-	ulint type;
 	static_assert(((UNIV_ZIP_SIZE_MIN >> 1) << 3) == 4096,
 		      "compatibility");
+#if defined _WIN32 || defined HAVE_FCNTL_DIRECT
+	ulint type;
 	switch (FSP_FLAGS_GET_ZIP_SSIZE(flags)) {
 	case 1:
 	case 2:
@@ -1911,6 +1916,9 @@ fil_ibd_create(
 	default:
 		type = OS_DATA_FILE;
 	}
+#else
+	constexpr auto type = OS_DATA_FILE;
+#endif
 
 	file = os_file_create(
 		innodb_data_file_key, path,
diff --git a/storage/innobase/fil/fil0pagecompress.cc b/storage/innobase/fil/fil0pagecompress.cc
index 16aea2a7e79..eaf4e04aa6b 100644
--- a/storage/innobase/fil/fil0pagecompress.cc
+++ b/storage/innobase/fil/fil0pagecompress.cc
@@ -49,11 +49,6 @@ Updated 14/02/2015
 #include "buf0lru.h"
 #include "ibuf0ibuf.h"
 #include "zlib.h"
-#ifdef __linux__
-#include <linux/fs.h>
-#include <sys/ioctl.h>
-#include <fcntl.h>
-#endif
 #include "row0mysql.h"
 #include "lz4.h"
 #include "lzo/lzo1x.h"
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index d76797037de..407834f2008 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -600,13 +600,7 @@ static PSI_rwlock_info all_innodb_rwlocks[] =
 #  ifdef BTR_CUR_HASH_ADAPT
   { &btr_search_latch_key, "btr_search_latch", 0 },
 #  endif
-  { &dict_operation_lock_key, "dict_operation_lock",
-#  ifdef UNIV_DEBUG
-    PSI_RWLOCK_FLAG_SX
-#  else
-    0
-#  endif
-  },
+  { &dict_operation_lock_key, "dict_operation_lock", 0 },
   { &fil_space_latch_key, "fil_space_latch", 0 },
   { &trx_i_s_cache_lock_key, "trx_i_s_cache_lock", 0 },
   { &trx_purge_latch_key, "trx_purge_latch", 0 },
@@ -4009,7 +4003,7 @@ static int innodb_init_params()
 
 	data_mysql_default_charset_coll = (ulint) default_charset_info->number;
 
-#ifndef _WIN32
+#ifdef HAVE_FCNTL_DIRECT
 	if (srv_use_atomic_writes && my_may_have_atomic_write) {
 		/*
                   Force O_DIRECT on Unixes (on Windows writes are always
@@ -4049,9 +4043,7 @@ static int innodb_init_params()
 	}
 #endif
 
-#ifndef _WIN32
-	ut_ad(srv_file_flush_method <= SRV_O_DIRECT_NO_FSYNC);
-#else
+#ifdef _WIN32
 	switch (srv_file_flush_method) {
 	case SRV_ALL_O_DIRECT_FSYNC + 1 /* "async_unbuffered"="unbuffered" */:
 		srv_file_flush_method = SRV_ALL_O_DIRECT_FSYNC;
@@ -4062,6 +4054,8 @@ static int innodb_init_params()
 	default:
 		ut_ad(srv_file_flush_method <= SRV_ALL_O_DIRECT_FSYNC);
 	}
+#else
+	ut_ad(srv_file_flush_method <= SRV_O_DIRECT_NO_FSYNC);
 #endif
 	innodb_buffer_pool_size_init();
 
@@ -13473,7 +13467,14 @@ int ha_innobase::delete_table(const char *name)
       /* FOREIGN KEY constraints cannot exist on partitioned tables. */;
 #endif
     else
-      err= lock_table_children(table, trx);
+    {
+      dict_sys.freeze(SRW_LOCK_CALL);
+      for (const dict_foreign_t* f : table->referenced_set)
+        if (dict_table_t* child= f->foreign_table)
+          if ((err= lock_table_for_trx(child, trx, LOCK_X)) != DB_SUCCESS)
+            break;
+      dict_sys.unfreeze();
+    }
   }
 
   dict_table_t *table_stats= nullptr, *index_stats= nullptr;
@@ -13871,7 +13872,14 @@ int ha_innobase::truncate()
   dict_table_t *table_stats = nullptr, *index_stats = nullptr;
   MDL_ticket *mdl_table = nullptr, *mdl_index = nullptr;
 
-  dberr_t error= lock_table_children(ib_table, trx);
+  dberr_t error= DB_SUCCESS;
+
+  dict_sys.freeze(SRW_LOCK_CALL);
+  for (const dict_foreign_t *f : ib_table->referenced_set)
+    if (dict_table_t *child= f->foreign_table)
+      if ((error= lock_table_for_trx(child, trx, LOCK_X)) != DB_SUCCESS)
+        break;
+  dict_sys.unfreeze();
 
   if (error == DB_SUCCESS)
     error= lock_table_for_trx(ib_table, trx, LOCK_X);
@@ -14062,7 +14070,16 @@ ha_innobase::rename_table(
 		/* There is no need to lock any FOREIGN KEY child tables. */
 	} else if (dict_table_t *table = dict_table_open_on_name(
 		    norm_from, false, DICT_ERR_IGNORE_FK_NOKEY)) {
-		error = lock_table_children(table, trx);
+		dict_sys.freeze(SRW_LOCK_CALL);
+		for (const dict_foreign_t* f : table->referenced_set) {
+			if (dict_table_t* child = f->foreign_table) {
+				error = lock_table_for_trx(child, trx, LOCK_X);
+				if (error != DB_SUCCESS) {
+					break;
+				}
+			}
+		}
+		dict_sys.unfreeze();
 		if (error == DB_SUCCESS) {
 			error = lock_table_for_trx(table, trx, LOCK_X);
 		}
diff --git a/storage/innobase/handler/handler0alter.cc b/storage/innobase/handler/handler0alter.cc
index 7fd4c3a30a2..1401136fba3 100644
--- a/storage/innobase/handler/handler0alter.cc
+++ b/storage/innobase/handler/handler0alter.cc
@@ -11224,7 +11224,16 @@ ha_innobase::commit_inplace_alter_table(
 			fts_optimize_remove_table(ctx->old_table);
 		}
 
-		error = lock_table_children(ctx->old_table, trx);
+		dict_sys.freeze(SRW_LOCK_CALL);
+		for (auto f : ctx->old_table->referenced_set) {
+			if (dict_table_t* child = f->foreign_table) {
+				error = lock_table_for_trx(child, trx, LOCK_X);
+				if (error != DB_SUCCESS) {
+					break;
+				}
+			}
+		}
+		dict_sys.unfreeze();
 
 		if (ctx->new_table->fts) {
 			ut_ad(!ctx->new_table->fts->add_wq);
diff --git a/storage/innobase/include/buf0buf.h b/storage/innobase/include/buf0buf.h
index 508b23c3b81..cd7cc294f16 100644
--- a/storage/innobase/include/buf0buf.h
+++ b/storage/innobase/include/buf0buf.h
@@ -1498,10 +1498,8 @@ public:
         n_chunks_new / 4 * chunks->size;
   }
 
-  /** @return whether the buffer pool has run out */
-  TPOOL_SUPPRESS_TSAN
-  bool ran_out() const
-  { return UNIV_UNLIKELY(!try_LRU_scan || !UT_LIST_GET_LEN(free)); }
+  /** @return whether the buffer pool is running low */
+  bool need_LRU_eviction() const;
 
   /** @return whether the buffer pool is shrinking */
   inline bool is_shrinking() const
@@ -1827,6 +1825,9 @@ public:
   Set whenever the free list grows, along with a broadcast of done_free.
   Protected by buf_pool.mutex. */
   Atomic_relaxed<bool> try_LRU_scan;
+  /** Whether we have warned to be running out of buffer pool */
+  std::atomic_flag LRU_warned;
+
 	/* @} */
 
 	/** @name LRU replacement algorithm fields */
diff --git a/storage/innobase/include/dict0dict.h b/storage/innobase/include/dict0dict.h
index 6e50c286df2..5fafb2c54e8 100644
--- a/storage/innobase/include/dict0dict.h
+++ b/storage/innobase/include/dict0dict.h
@@ -1313,14 +1313,14 @@ class dict_sys_t
   /** The my_hrtime_coarse().val of the oldest lock_wait() start, or 0 */
   std::atomic<ulonglong> latch_ex_wait_start;
 
-#ifdef UNIV_DEBUG
-  typedef index_lock dict_lock;
-#else
-  typedef srw_lock dict_lock;
-#endif
-
   /** the rw-latch protecting the data dictionary cache */
-  alignas(CPU_LEVEL1_DCACHE_LINESIZE) dict_lock latch;
+  alignas(CPU_LEVEL1_DCACHE_LINESIZE) srw_lock latch;
+#ifdef UNIV_DEBUG
+  /** whether latch is being held in exclusive mode (by any thread) */
+  Atomic_relaxed<pthread_t> latch_ex;
+  /** number of S-latch holders */
+  Atomic_counter<uint32_t> latch_readers;
+#endif
 public:
   /** Indexes of SYS_TABLE[] */
   enum
@@ -1488,12 +1488,15 @@ public:
   }
 
 #ifdef UNIV_DEBUG
-  /** @return whether the current thread is holding the latch */
-  bool frozen() const { return latch.have_any(); }
-  /** @return whether the current thread is holding a shared latch */
-  bool frozen_not_locked() const { return latch.have_s(); }
+  /** @return whether any thread (not necessarily the current thread)
+  is holding the latch; that is, this check may return false
+  positives */
+  bool frozen() const { return latch_readers || latch_ex; }
+  /** @return whether any thread (not necessarily the current thread)
+  is holding a shared latch */
+  bool frozen_not_locked() const { return latch_readers; }
   /** @return whether the current thread holds the exclusive latch */
-  bool locked() const { return latch.have_x(); }
+  bool locked() const { return latch_ex == pthread_self(); }
 #endif
 private:
   /** Acquire the exclusive latch */
@@ -1508,12 +1511,13 @@ public:
   /** Exclusively lock the dictionary cache. */
   void lock(SRW_LOCK_ARGS(const char *file, unsigned line))
   {
-#ifdef UNIV_DEBUG
-    ut_ad(!latch.have_any());
-    if (!latch.x_lock_try())
-#else
-    if (!latch.wr_lock_try())
-#endif
+    if (latch.wr_lock_try())
+    {
+      ut_ad(!latch_readers);
+      ut_ad(!latch_ex);
+      ut_d(latch_ex= pthread_self());
+    }
+    else
       lock_wait(SRW_LOCK_ARGS(file, line));
   }
 
@@ -1528,30 +1532,24 @@ public:
   /** Unlock the data dictionary cache. */
   void unlock()
   {
-# ifdef UNIV_DEBUG
-    latch.x_unlock();
-# else
+    ut_ad(latch_ex == pthread_self());
+    ut_ad(!latch_readers);
+    ut_d(latch_ex= 0);
     latch.wr_unlock();
-# endif
   }
   /** Acquire a shared lock on the dictionary cache. */
   void freeze()
   {
-# ifdef UNIV_DEBUG
-    ut_ad(!latch.have_any());
-    latch.s_lock();
-# else
     latch.rd_lock();
-# endif
+    ut_ad(!latch_ex);
+    ut_d(latch_readers++);
   }
   /** Release a shared lock on the dictionary cache. */
   void unfreeze()
   {
-# ifdef UNIV_DEBUG
-    latch.s_unlock();
-# else
+    ut_ad(!latch_ex);
+    ut_ad(latch_readers--);
     latch.rd_unlock();
-# endif
   }
 #endif
 
diff --git a/storage/innobase/include/lock0lock.h b/storage/innobase/include/lock0lock.h
index 65537859924..59ee7f551b4 100644
--- a/storage/innobase/include/lock0lock.h
+++ b/storage/innobase/include/lock0lock.h
@@ -438,13 +438,6 @@ dberr_t lock_table_for_trx(dict_table_t *table, trx_t *trx, lock_mode mode,
                            bool no_wait= false)
 	MY_ATTRIBUTE((nonnull, warn_unused_result));
 
-/** Lock the child tables of a table.
-@param table    parent table
-@param trx      transaction
-@return error code */
-dberr_t lock_table_children(dict_table_t *table, trx_t *trx)
-	MY_ATTRIBUTE((nonnull, warn_unused_result));
-
 /** Exclusively lock the data dictionary tables.
 @param trx  dictionary transaction
 @return error code
diff --git a/storage/innobase/include/os0file.h b/storage/innobase/include/os0file.h
index c9db6a1fb09..c8374515859 100644
--- a/storage/innobase/include/os0file.h
+++ b/storage/innobase/include/os0file.h
@@ -142,9 +142,11 @@ static const ulint OS_FILE_NORMAL = 62;
 /* @} */
 
 /** Types for file create @{ */
-static const ulint OS_DATA_FILE = 100;
-static const ulint OS_LOG_FILE = 101;
-static const ulint OS_DATA_FILE_NO_O_DIRECT = 103;
+static constexpr ulint OS_DATA_FILE = 100;
+static constexpr ulint OS_LOG_FILE = 101;
+#if defined _WIN32 || defined HAVE_FCNTL_DIRECT
+static constexpr ulint OS_DATA_FILE_NO_O_DIRECT = 103;
+#endif
 /* @} */
 
 /** Error codes from os_file_get_last_error @{ */
@@ -373,7 +375,7 @@ os_file_create_simple_no_error_handling_func(
 	bool*		success)
 	MY_ATTRIBUTE((warn_unused_result));
 
-#ifdef  _WIN32
+#ifndef HAVE_FCNTL_DIRECT
 #define os_file_set_nocache(fd, file_name, operation_name) do{}while(0)
 #else
 /** Tries to disable OS caching on an opened file descriptor.
diff --git a/storage/innobase/lock/lock0lock.cc b/storage/innobase/lock/lock0lock.cc
index c9072998e66..df51ceb16d8 100644
--- a/storage/innobase/lock/lock0lock.cc
+++ b/storage/innobase/lock/lock0lock.cc
@@ -3940,8 +3940,6 @@ static void lock_table_dequeue(lock_t *in_lock, bool owns_wait_mutex)
 dberr_t lock_table_for_trx(dict_table_t *table, trx_t *trx, lock_mode mode,
                            bool no_wait)
 {
-  ut_ad(!dict_sys.frozen());
-
   mem_heap_t *heap= mem_heap_create(512);
   sel_node_t *node= sel_node_create(heap);
   que_thr_t *thr= pars_complete_graph_for_exec(node, trx, heap, nullptr);
@@ -3978,36 +3976,6 @@ run_again:
   return err;
 }
 
-/** Lock the child tables of a table.
-@param table    parent table
-@param trx      transaction
-@return error code */
-dberr_t lock_table_children(dict_table_t *table, trx_t *trx)
-{
-  dict_sys.freeze(SRW_LOCK_CALL);
-  std::vector<dict_table_t*> children;
-
-  for (auto f : table->referenced_set)
-    if (dict_table_t *child= f->foreign_table)
-    {
-      child->acquire();
-      children.emplace_back(child);
-    }
-  dict_sys.unfreeze();
-
-  dberr_t err= DB_SUCCESS;
-
-  for (auto child : children)
-    if ((err= lock_table_for_trx(child, trx, LOCK_X)) != DB_SUCCESS)
-      break;
-
-  for (auto child : children)
-    child->release();
-
-  return err;
-}
-
-
 /** Exclusively lock the data dictionary tables.
 @param trx  dictionary transaction
 @return error code
diff --git a/storage/innobase/log/log0recv.cc b/storage/innobase/log/log0recv.cc
index 68d45fb1f90..e72f842f9a9 100644
--- a/storage/innobase/log/log0recv.cc
+++ b/storage/innobase/log/log0recv.cc
@@ -4910,16 +4910,20 @@ uint32_t recv_dblwr_t::find_first_page(const char *name, pfs_os_file_t file)
     for (const page_t *page : pages)
     {
       uint32_t space_id= page_get_space_id(page);
+      byte *read_page= nullptr;
       if (page_get_page_no(page) > 0 || space_id == 0)
+      {
 next_page:
+        aligned_free(read_page);
         continue;
+      }
       uint32_t flags= mach_read_from_4(
         FSP_HEADER_OFFSET + FSP_SPACE_FLAGS + page);
       page_id_t page_id(space_id, 0);
       size_t page_size= fil_space_t::physical_size(flags);
       if (file_size < 4 * page_size)
         goto next_page;
-      byte *read_page=
+      read_page=
         static_cast<byte*>(aligned_malloc(3 * page_size, page_size));
       /* Read 3 pages from the file and match the space id
       with the space id which is stored in
@@ -4931,7 +4935,10 @@ next_page:
       {
         byte *cur_page= read_page + j * page_size;
         if (buf_is_zeroes(span<const byte>(cur_page, page_size)))
-          return 0;
+        {
+          space_id= 0;
+          goto early_exit;
+        }
         if (mach_read_from_4(cur_page + FIL_PAGE_OFFSET) != j + 1 ||
             memcmp(cur_page + FIL_PAGE_SPACE_ID,
                    page + FIL_PAGE_SPACE_ID, 4) ||
@@ -4939,7 +4946,11 @@ next_page:
           goto next_page;
       }
       if (!restore_first_page(space_id, name, file))
+      {
+early_exit:
+        aligned_free(read_page);
         return space_id;
+      }
       break;
     }
   }
diff --git a/storage/innobase/os/os0file.cc b/storage/innobase/os/os0file.cc
index e8f533c2f89..afdc3522df0 100644
--- a/storage/innobase/os/os0file.cc
+++ b/storage/innobase/os/os0file.cc
@@ -975,7 +975,7 @@ os_file_create_simple_func(
 	*success = false;
 
 	int		create_flag;
-	const char*	mode_str	= NULL;
+	const char*	mode_str __attribute__((unused));
 
 	ut_a(!(create_mode & OS_FILE_ON_ERROR_SILENT));
 	ut_a(!(create_mode & OS_FILE_ON_ERROR_NO_EXIT));
@@ -1051,6 +1051,7 @@ os_file_create_simple_func(
 
 	} while (retry);
 
+#ifdef HAVE_FCNTL_DIRECT
 	/* This function is always called for data files, we should disable
 	OS caching (O_DIRECT) here as we do in os_file_create_func(), so
 	we open the same file in the same mode, see man page of open(2). */
@@ -1065,6 +1066,7 @@ os_file_create_simple_func(
 			break;
 		}
 	}
+#endif
 
 #ifndef _WIN32
 	if (!read_only
@@ -1150,7 +1152,7 @@ os_file_create_func(
 	);
 
 	int		create_flag;
-	const char*	mode_str	= NULL;
+	const char*	mode_str __attribute__((unused));
 
 	on_error_no_exit = create_mode & OS_FILE_ON_ERROR_NO_EXIT
 		? true : false;
@@ -1192,10 +1194,13 @@ os_file_create_func(
 		return(OS_FILE_CLOSED);
 	}
 
+#ifdef HAVE_FCNTL_DIRECT
 	ut_a(type == OS_LOG_FILE
 	     || type == OS_DATA_FILE
 	     || type == OS_DATA_FILE_NO_O_DIRECT);
-
+#else
+	ut_a(type == OS_LOG_FILE || type == OS_DATA_FILE);
+#endif
 	ut_a(purpose == OS_FILE_AIO || purpose == OS_FILE_NORMAL);
 
 	/* We let O_DSYNC only affect log files */
@@ -1241,7 +1246,7 @@ os_file_create_func(
 		return file;
 	}
 
-#if (defined __sun__ && defined DIRECTIO_ON) || defined O_DIRECT
+#ifdef HAVE_FCNTL_DIRECT
 	if (type == OS_DATA_FILE) {
 		switch (srv_file_flush_method) {
 		case SRV_O_DSYNC:
@@ -2175,10 +2180,8 @@ os_file_create_func(
 		if (srv_file_flush_method == SRV_O_DSYNC)
 			attributes|= FILE_FLAG_WRITE_THROUGH;
 	}
-	else if (type == OS_DATA_FILE)
-	{
-		switch (srv_file_flush_method)
-		{
+	else if (type == OS_DATA_FILE) {
+		switch (srv_file_flush_method) {
 		case SRV_FSYNC:
 		case SRV_LITTLESYNC:
 		case SRV_NOSYNC:
@@ -3042,30 +3045,15 @@ os_file_handle_error_cond_exit(
 	return(false);
 }
 
-#ifndef _WIN32
+#ifdef HAVE_FCNTL_DIRECT
 /** Tries to disable OS caching on an opened file descriptor.
 @param[in]	fd		file descriptor to alter
 @param[in]	file_name	file name, used in the diagnostic message
 @param[in]	name		"open" or "create"; used in the diagnostic
 				message */
 void
-os_file_set_nocache(
-	int	fd		MY_ATTRIBUTE((unused)),
-	const char*	file_name	MY_ATTRIBUTE((unused)),
-	const char*	operation_name	MY_ATTRIBUTE((unused)))
+os_file_set_nocache(int fd, const char *file_name, const char *operation_name)
 {
-	/* some versions of Solaris may not have DIRECTIO_ON */
-#if defined(__sun__) && defined(DIRECTIO_ON)
-	if (directio(fd, DIRECTIO_ON) == -1) {
-		int	errno_save = errno;
-
-		ib::error()
-			<< "Failed to set DIRECTIO_ON on file "
-			<< file_name << "; " << operation_name << ": "
-			<< strerror(errno_save) << ","
-			" continuing anyway.";
-	}
-#elif defined(O_DIRECT)
 	if (fcntl(fd, F_SETFL, O_DIRECT) == -1) {
 		int		errno_save = errno;
 		static bool	warning_message_printed = false;
@@ -3084,10 +3072,8 @@ os_file_set_nocache(
 				<< ", continuing anyway.";
 		}
 	}
-#endif /* defined(__sun__) && defined(DIRECTIO_ON) */
 }
-
-#endif /* _WIN32 */
+#endif /* HAVE_FCNTL_DIRECT */
 
 /** Check if the file system supports sparse files.
 @param fh	file handle
@@ -3457,7 +3443,7 @@ static void write_io_callback(void *c)
 
   if (UNIV_UNLIKELY(cb->m_err != 0))
     ib::info () << "IO Error: " << cb->m_err
-                << "during write of "
+                << " during write of "
                 << cb->m_len << " bytes, for file "
                 << request.node->name << "(" << cb->m_fh << "), returned "
                 << cb->m_ret_len;
diff --git a/storage/innobase/row/row0merge.cc b/storage/innobase/row/row0merge.cc
index c5b88538e7b..188d8ba5a96 100644
--- a/storage/innobase/row/row0merge.cc
+++ b/storage/innobase/row/row0merge.cc
@@ -4411,13 +4411,14 @@ row_merge_file_create(
 	merge_file->fd = row_merge_file_create_low(path);
 	merge_file->offset = 0;
 	merge_file->n_rec = 0;
-
+#ifdef HAVE_FCNTL_DIRECT
 	if (merge_file->fd != OS_FILE_CLOSED) {
 		if (srv_disable_sort_file_cache) {
 			os_file_set_nocache(merge_file->fd,
 				"row0merge.cc", "sort");
 		}
 	}
+#endif
 	return(merge_file->fd);
 }
 
diff --git a/storage/perfschema/CMakeLists.txt b/storage/perfschema/CMakeLists.txt
index b4f5e96b607..e703e43fe50 100644
--- a/storage/perfschema/CMakeLists.txt
+++ b/storage/perfschema/CMakeLists.txt
@@ -24,7 +24,7 @@ INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/include
                     ${CMAKE_SOURCE_DIR}/sql
                     ${CMAKE_BINARY_DIR}/sql
                     ${CMAKE_CURRENT_BINARY_DIR}
-                    ${PCRE_INCLUDES}
+                    ${PCRE_INCLUDE_DIRS}
                     ${SSL_INCLUDE_DIRS})
 
 ADD_DEFINITIONS(-DMYSQL_SERVER)
diff --git a/storage/perfschema/unittest/CMakeLists.txt b/storage/perfschema/unittest/CMakeLists.txt
index 2a22990f807..600795c78fc 100644
--- a/storage/perfschema/unittest/CMakeLists.txt
+++ b/storage/perfschema/unittest/CMakeLists.txt
@@ -22,7 +22,7 @@
 
 INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/include
                     ${CMAKE_SOURCE_DIR}/include/mysql
-                    ${PCRE_INCLUDES}
+                    ${PCRE_INCLUDE_DIRS}
                     ${CMAKE_SOURCE_DIR}/sql
                     ${SSL_INCLUDE_DIRS}
                     ${CMAKE_SOURCE_DIR}/unittest/mytap
diff --git a/storage/spider/mysql-test/spider/bugfix/t/perfschema.opt b/storage/spider/mysql-test/spider/bugfix/t/perfschema.opt
index 611d08f0c78..d2ed32ddf34 100644
--- a/storage/spider/mysql-test/spider/bugfix/t/perfschema.opt
+++ b/storage/spider/mysql-test/spider/bugfix/t/perfschema.opt
@@ -1 +1 @@
---performance-schema
+--loose-performance-schema
diff --git a/storage/spider/mysql-test/spider/bugfix/t/perfschema.test b/storage/spider/mysql-test/spider/bugfix/t/perfschema.test
index 2f1a961a513..9346d2b5aa3 100644
--- a/storage/spider/mysql-test/spider/bugfix/t/perfschema.test
+++ b/storage/spider/mysql-test/spider/bugfix/t/perfschema.test
@@ -1,3 +1,4 @@
+source include/have_perfschema.inc;
 disable_query_log;
 source ../../include/init_spider.inc;
 enable_query_log;
diff --git a/unittest/embedded/CMakeLists.txt b/unittest/embedded/CMakeLists.txt
index cf48550c377..428bb811de6 100644
--- a/unittest/embedded/CMakeLists.txt
+++ b/unittest/embedded/CMakeLists.txt
@@ -1,7 +1,7 @@
 
 INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/include
                     ${CMAKE_SOURCE_DIR}/libmysqld/include
-                    ${PCRE_INCLUDES}
+                    ${PCRE_INCLUDE_DIRS}
                     ${CMAKE_SOURCE_DIR}/sql
                     ${MY_READLINE_INCLUDE_DIR}
                     )