Add summary of changes regarding 'max_threads' to ChangeLog.rst

Update the change log file with the summary of API changes related
to the 'max_threads' changes.

diff --git a/ChangeLog.rst b/ChangeLog.rst
index f4cb07ce6ac745efcd0995f164851efd0452a94b..08df4a88548cc37ffd0c24d596c9c656a99c36e2 100644 (file)
--- a/ChangeLog.rst
+++ b/ChangeLog.rst
@@ -1,3 +1,58 @@
+libfuse 3.12.0 (<unreleased>)
+===========================
+* The 'max_idle_threads' parameter has performance implication
+  due to run time thread creation and destruction per request
+  and it is deprecated in favor of the new max_threads parameter.
+
+  * API changes:
+    In order to avoid future version symboling and also to
+    allow to set fuse_loop_config defaults an API change has been
+    introduced beginning with API version (FUSE_USE_VERSION) 312.
+    'struct fuse_loop_config' is now private and has to be
+    constructed using fuse_loop_cfg_create(). Besides allocating
+    memory this function also sets struct member default.
+    Desctruction (free) is done through fuse_loop_cfg_destroy().
+    Struct parameters can be changed using fuse_loop_cfg_set_*()
+    functions.
+    New  functions regarding the fuse-loop configuration are:
+      fuse_loop_cfg_create
+      fuse_loop_cfg_destroy
+      fuse_loop_cfg_set_idle_threads
+      fuse_loop_cfg_set_max_threads
+      fuse_loop_cfg_set_clone_fd
+      fuse_loop_cfg_convert (internal for API/ABI compatibility)
+    Functions details can be found in fuse_common.h
+
+    In API version 312 the fuse_session_loop_mt() function now
+    also accepts struct fuse_loop_config * as NULL pointer and
+    uses defaults then.
+
+  * Users of fuse_parse_cmdline() get the new option
+    'max_threads' with API version 312.
+
+  * File system conversion help:
+    - See example/passthrough_hp.cc
+
+    #define FUSE_USE_VERSION FUSE_MAKE_VERSION(3, 12)
+
+    ...
+    main(int argc, char *argv[])
+    ...
+    struct fuse_loop_config *loop_config;
+    ...
+    loop_config = fuse_loop_cfg_create();
+    ...
+    ret = fuse_session_loop_mt(se, loop_config);
+    ...
+    fuse_loop_cfg_destroy(loop_config);
+
+  * Further notes:
+    Using max_threads == 1 and calling fuse_session_loop_mt() works,
+    it will run single threaded similar to fuse_session_loop(). In
+    fact, fuse_session_loop() might get deprecated in future
+    versions.
+
+
 libfuse 3.11.0 (2022-05-02)
 ===========================