diff options
Diffstat (limited to 'system/xen/xsa/xsa206-4.8-0009-oxenstored-discard-old-commit-history-on-txn-end.patch')
| -rw-r--r-- | system/xen/xsa/xsa206-4.8-0009-oxenstored-discard-old-commit-history-on-txn-end.patch | 141 |
1 files changed, 0 insertions, 141 deletions
diff --git a/system/xen/xsa/xsa206-4.8-0009-oxenstored-discard-old-commit-history-on-txn-end.patch b/system/xen/xsa/xsa206-4.8-0009-oxenstored-discard-old-commit-history-on-txn-end.patch deleted file mode 100644 index f1734c8375..0000000000 --- a/system/xen/xsa/xsa206-4.8-0009-oxenstored-discard-old-commit-history-on-txn-end.patch +++ /dev/null @@ -1,141 +0,0 @@ -From 66bdbbc41a45d2bf59ddb4ff26c52c1cc546f720 Mon Sep 17 00:00:00 2001 -From: Thomas Sanders <thomas.sanders@citrix.com> -Date: Thu, 23 Mar 2017 14:25:16 +0000 -Subject: [PATCH 09/15] oxenstored: discard old commit-history on txn end - -The history of commits is to be used for working out which historical -commit(s) (including atomic writes) caused conflicts with a -currently-failing commit of a transaction. Any commit that was made -before the current transaction started cannot be relevant. Therefore -we never need to keep history from before the start of the -longest-running transaction that is open at any given time: whenever a -transaction ends (with or without a commit) then if it was the -longest-running open transaction we can delete history up until start -of the the next-longest-running open transaction. - -Some transactions might stay open for a very long time, so if any -transaction exceeds conflict_max_history_seconds then we remove it -from consideration in this context, and will not guarantee to keep -remembering about historical commits made during such a transaction. - -We implement this by keeping a list of all open transactions that have -not been open too long. When a transaction ends, we remove it from the -list, along with any that have been open longer than the maximum; then -we delete any history from before the start of the longest-running -transaction remaining in the list. - -Reported-by: Juergen Gross <jgross@suse.com> -Signed-off-by: Thomas Sanders <thomas.sanders@citrix.com> -Reviewed-by: Jonathan Davies <jonathan.davies@citrix.com> -Reviewed-by: Christian Lindig <christian.lindig@citrix.com> ---- - tools/ocaml/xenstored/history.ml | 17 +++++++++++++++++ - tools/ocaml/xenstored/process.ml | 4 ++-- - tools/ocaml/xenstored/transaction.ml | 29 +++++++++++++++++++++++++---- - 3 files changed, 44 insertions(+), 6 deletions(-) - -diff --git a/tools/ocaml/xenstored/history.ml b/tools/ocaml/xenstored/history.ml -index e4b4d70..6f7a282 100644 ---- a/tools/ocaml/xenstored/history.ml -+++ b/tools/ocaml/xenstored/history.ml -@@ -36,6 +36,23 @@ let mark_symbols () = - ) - !history - -+(* Keep only enough commit-history to protect the running transactions that we are still tracking *) -+(* There is scope for optimisation here, replacing List.filter with something more efficient, -+ * probably on a different list-like structure. *) -+let trim () = -+ history := match Transaction.oldest_short_running_transaction () with -+ | None -> [] (* We have no open transaction, so no history is needed *) -+ | Some (_, txn) -> ( -+ (* keep records with finish_count recent enough to be relevant *) -+ List.filter (fun r -> r.finish_count > txn.Transaction.start_count) !history -+ ) -+ -+let end_transaction txn con tid commit = -+ let success = Connection.end_transaction con tid commit in -+ Transaction.end_transaction txn; -+ trim (); -+ success -+ - let push (x: history_record) = - let dom = x.con.Connection.dom in - match dom with -diff --git a/tools/ocaml/xenstored/process.ml b/tools/ocaml/xenstored/process.ml -index b435a4a..6f4d118 100644 ---- a/tools/ocaml/xenstored/process.ml -+++ b/tools/ocaml/xenstored/process.ml -@@ -313,7 +313,7 @@ let transaction_replay c t doms cons = - false - | Transaction.Full(id, oldstore, cstore) -> - let tid = Connection.start_transaction c cstore in -- let new_t = Transaction.make tid cstore in -+ let new_t = Transaction.make ~internal:true tid cstore in - let con = sprintf "r(%d):%s" id (Connection.get_domstr c) in - let perform_exn (request, response) = - write_access_log ~ty:request.Packet.ty ~tid ~con ~data:request.Packet.data; -@@ -370,7 +370,7 @@ let do_transaction_end con t domains cons data = - in - let success = - let commit = if commit then Some (fun con trans -> transaction_replay con trans domains cons) else None in -- Connection.end_transaction con (Transaction.get_id t) commit in -+ History.end_transaction t con (Transaction.get_id t) commit in - if not success then - raise Transaction_again; - if commit then begin -diff --git a/tools/ocaml/xenstored/transaction.ml b/tools/ocaml/xenstored/transaction.ml -index b1791b3..edd1178 100644 ---- a/tools/ocaml/xenstored/transaction.ml -+++ b/tools/ocaml/xenstored/transaction.ml -@@ -87,12 +87,29 @@ type t = { - mutable read_lowpath: Store.Path.t option; - mutable write_lowpath: Store.Path.t option; - } -+let get_id t = match t.ty with No -> none | Full (id, _, _) -> id - - let counter = ref 0L - --let make id store = -+(* Scope for optimisation: different data-structure and functions to search/filter it *) -+let short_running_txns = ref [] -+ -+let oldest_short_running_transaction () = -+ let rec last = function -+ | [] -> None -+ | [x] -> Some x -+ | x :: xs -> last xs -+ in last !short_running_txns -+ -+let end_transaction txn = -+ let cutoff = Unix.gettimeofday () -. !Define.conflict_max_history_seconds in -+ short_running_txns := List.filter -+ (function (start_time, tx) -> start_time >= cutoff && tx != txn) -+ !short_running_txns -+ -+let make ?(internal=false) id store = - let ty = if id = none then No else Full(id, Store.copy store, store) in -- { -+ let txn = { - ty = ty; - start_count = !counter; - store = if id = none then store else Store.copy store; -@@ -101,9 +118,13 @@ let make id store = - operations = []; - read_lowpath = None; - write_lowpath = None; -- } -+ } in -+ if id <> none && not internal then ( -+ let now = Unix.gettimeofday () in -+ short_running_txns := (now, txn) :: !short_running_txns -+ ); -+ txn - --let get_id t = match t.ty with No -> none | Full (id, _, _) -> id - let get_store t = t.store - let get_paths t = t.paths - --- -2.1.4 - |