Xen 4.16.4-pre-patchset-04.16.4-pre-patchset-0

Signed-off-by: Tomáš Mózes <hydrapolic@gmail.com>

1 files changed, 0 insertions, 126 deletions

diff --git a/0064-tools-ocaml-GC-parameter-tuning.patch b/0064-tools-ocaml-GC-parameter-tuning.patch
deleted file mode 100644
index 6c80e2d..0000000
--- a/0064-tools-ocaml-GC-parameter-tuning.patch
+++ /dev/null
@@ -1,126 +0,0 @@
-From a63bbcf5318b487ca86574d7fcf916958af5ed02 Mon Sep 17 00:00:00 2001
-From: =?UTF-8?q?Edwin=20T=C3=B6r=C3=B6k?= <edvin.torok@citrix.com>
-Date: Wed, 12 Oct 2022 19:13:07 +0100
-Subject: [PATCH 64/87] tools/ocaml: GC parameter tuning
-MIME-Version: 1.0
-Content-Type: text/plain; charset=UTF-8
-Content-Transfer-Encoding: 8bit
-
-By default the OCaml garbage collector would return memory to the OS only
-after unused memory is 5x live memory.  Tweak this to 120% instead, which
-would match the major GC speed.
-
-This is part of XSA-326.
-
-Signed-off-by: Edwin Török <edvin.torok@citrix.com>
-Acked-by: Christian Lindig <christian.lindig@citrix.com>
-(cherry picked from commit 4a8bacff20b857ca0d628ef5525877ade11f2a42)
----
- tools/ocaml/xenstored/define.ml    |  1 +
- tools/ocaml/xenstored/xenstored.ml | 64 ++++++++++++++++++++++++++++++
- 2 files changed, 65 insertions(+)
-
-diff --git a/tools/ocaml/xenstored/define.ml b/tools/ocaml/xenstored/define.ml
-index 6b06f808595b..ba63a8147e09 100644
---- a/tools/ocaml/xenstored/define.ml
-+++ b/tools/ocaml/xenstored/define.ml
-@@ -25,6 +25,7 @@ let maxwatch = ref (100)
- let maxtransaction = ref (10)
- let maxrequests = ref (1024)   (* maximum requests per transaction *)
- 
-+let gc_max_overhead = ref 120 (* 120% see comment in xenstored.ml *)
- let conflict_burst_limit = ref 5.0
- let conflict_max_history_seconds = ref 0.05
- let conflict_rate_limit_is_aggregate = ref true
-diff --git a/tools/ocaml/xenstored/xenstored.ml b/tools/ocaml/xenstored/xenstored.ml
-index d44ae673c42a..3b57ad016dfb 100644
---- a/tools/ocaml/xenstored/xenstored.ml
-+++ b/tools/ocaml/xenstored/xenstored.ml
-@@ -104,6 +104,7 @@ let parse_config filename =
- 		("quota-maxsize", Config.Set_int Quota.maxsize);
- 		("quota-maxrequests", Config.Set_int Define.maxrequests);
- 		("quota-path-max", Config.Set_int Define.path_max);
-+		("gc-max-overhead", Config.Set_int Define.gc_max_overhead);
- 		("test-eagain", Config.Set_bool Transaction.test_eagain);
- 		("persistent", Config.Set_bool Disk.enable);
- 		("xenstored-log-file", Config.String Logging.set_xenstored_log_destination);
-@@ -265,6 +266,67 @@ let to_file store cons fds file =
- 	        (fun () -> close_out channel)
- end
- 
-+(*
-+	By default OCaml's GC only returns memory to the OS when it exceeds a
-+	configurable 'max overhead' setting.
-+	The default is 500%, that is 5/6th of the OCaml heap needs to be free
-+	and only 1/6th live for a compaction to be triggerred that would
-+	release memory back to the OS.
-+	If the limit is not hit then the OCaml process can reuse that memory
-+	for its own purposes, but other processes won't be able to use it.
-+
-+	There is also a 'space overhead' setting that controls how much work
-+	each major GC slice does, and by default aims at having no more than
-+	80% or 120% (depending on version) garbage values compared to live
-+	values.
-+	This doesn't have as much relevance to memory returned to the OS as
-+	long as space_overhead <= max_overhead, because compaction is only
-+	triggerred at the end of major GC cycles.
-+
-+	The defaults are too large once the program starts using ~100MiB of
-+	memory, at which point ~500MiB would be unavailable to other processes
-+	(which would be fine if this was the main process in this VM, but it is
-+	not).
-+
-+	Max overhead can also be set to 0, however this is for testing purposes
-+	only (setting it lower than 'space overhead' wouldn't help because the
-+	major GC wouldn't run fast enough, and compaction does have a
-+	performance cost: we can only compact contiguous regions, so memory has
-+	to be moved around).
-+
-+	Max overhead controls how often the heap is compacted, which is useful
-+	if there are burst of activity followed by long periods of idle state,
-+	or if a domain quits, etc. Compaction returns memory to the OS.
-+
-+	wasted = live * space_overhead / 100
-+
-+	For globally overriding the GC settings one can use OCAMLRUNPARAM,
-+	however we provide a config file override to be consistent with other
-+	oxenstored settings.
-+
-+	One might want to dynamically adjust the overhead setting based on used
-+	memory, i.e. to use a fixed upper bound in bytes, not percentage. However
-+	measurements show that such adjustments increase GC overhead massively,
-+	while still not guaranteeing that memory is returned any more quickly
-+	than with a percentage based setting.
-+
-+	The allocation policy could also be tweaked, e.g. first fit would reduce
-+	fragmentation and thus memory usage, but the documentation warns that it
-+	can be sensibly slower, and indeed one of our own testcases can trigger
-+	such a corner case where it is multiple times slower, so it is best to keep
-+	the default allocation policy (next-fit/best-fit depending on version).
-+
-+	There are other tweaks that can be attempted in the future, e.g. setting
-+	'ulimit -v' to 75% of RAM, however getting the kernel to actually return
-+	NULL from allocations is difficult even with that setting, and without a
-+	NULL the emergency GC won't be triggerred.
-+	Perhaps cgroup limits could help, but for now tweak the safest only.
-+*)
-+
-+let tweak_gc () =
-+	Gc.set { (Gc.get ()) with Gc.max_overhead = !Define.gc_max_overhead }
-+
-+
- let _ =
- 	let cf = do_argv in
- 	let pidfile =
-@@ -274,6 +336,8 @@ let _ =
- 			default_pidfile
- 		in
- 
-+	tweak_gc ();
-+
- 	(try
- 		Unixext.mkdir_rec (Filename.dirname pidfile) 0o755
- 	with _ ->
--- 
-2.37.4
-