[Xen-changelog] [xen stable-4.4] oxenstored: only process domain connections that notify us by events

[patchbot@xxxxxxx]

commit 04386b51c65088e306bf8b199a8bab3a2c196a1a
Author:     Zheng Li <dev@xxxxxxxx>
AuthorDate: Fri Mar 24 17:03:31 2017 +0000
Commit:     Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CommitDate: Wed Apr 5 15:26:37 2017 +0100

    oxenstored: only process domain connections that notify us by events
    
    Currently, upon receiving an event, oxenstored will always scan/process all
    the domain connections (xs rings), disregarding which domain sent that 
event.
    This is rather costy and inefficient. It also shadows and indulges client
    for not correctly communicating with us on message/space availability.
    
    With this patch, oxenstore will only scan/process the domain connections
    that have correctly notified us by events or have IO actions leftover from
    previous communication.
    
    Reported-by: Juergen Gross <jgross@xxxxxxxx>
    Signed-off-by: Zheng Li <dev@xxxxxxxx>
    Reviewed-by: David Scott <dave.scott@xxxxxxxxxx>
---
 tools/ocaml/xenstored/connection.ml  |  4 ++++
 tools/ocaml/xenstored/connections.ml |  9 ++++-----
 tools/ocaml/xenstored/xenstored.ml   | 13 ++++++++++---
 3 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/tools/ocaml/xenstored/connection.ml 
b/tools/ocaml/xenstored/connection.ml
index 47695f8..807fc00 100644
--- a/tools/ocaml/xenstored/connection.ml
+++ b/tools/ocaml/xenstored/connection.ml
@@ -223,10 +223,14 @@ let pop_in con = Xenbus.Xb.get_in_packet con.xb
 let has_more_input con = Xenbus.Xb.has_more_input con.xb
 
 let has_output con = Xenbus.Xb.has_output con.xb
+let has_old_output con = Xenbus.Xb.has_old_output con.xb
 let has_new_output con = Xenbus.Xb.has_new_output con.xb
 let peek_output con = Xenbus.Xb.peek_output con.xb
 let do_output con = Xenbus.Xb.output con.xb
 
+let has_more_work con =
+       has_more_input con || not (has_old_output con) && has_new_output con
+
 let incr_ops con = con.stat_nb_ops <- con.stat_nb_ops + 1
 
 let mark_symbols con =
diff --git a/tools/ocaml/xenstored/connections.ml 
b/tools/ocaml/xenstored/connections.ml
index 1c8d911..f9bc225 100644
--- a/tools/ocaml/xenstored/connections.ml
+++ b/tools/ocaml/xenstored/connections.ml
@@ -98,11 +98,10 @@ let iter cons fct =
        iter_domains cons fct; iter_anonymous cons fct
 
 let has_more_work cons =
-       Hashtbl.fold (fun id con acc ->
-               if Connection.has_more_input con then
-                       con :: acc
-               else
-                       acc) cons.domains []
+       Hashtbl.fold
+               (fun id con acc ->
+                if Connection.has_more_work con then con :: acc else acc)
+               cons.domains []
 
 let key_of_str path =
        if path.[0] = '@'
diff --git a/tools/ocaml/xenstored/xenstored.ml 
b/tools/ocaml/xenstored/xenstored.ml
index d74846c..4a1d027 100644
--- a/tools/ocaml/xenstored/xenstored.ml
+++ b/tools/ocaml/xenstored/xenstored.ml
@@ -57,7 +57,10 @@ let process_domains store cons domains =
                        let con = Connections.find_domain cons (Domain.get_id 
domain) in
                                Process.do_input store cons domains con;
                                Process.do_output store cons domains con in
-       Domains.iter domains do_io_domain
+       List.iter
+               (fun c ->
+                match Connection.get_domain c with
+                | Some d -> do_io_domain d | _ -> ())
 
 let sigusr1_handler store =
        try
@@ -303,6 +306,7 @@ let _ =
                        Connections.add_anonymous cons cfd can_write
                and handle_eventchn fd =
                        let port = Event.pending eventchn in
+                       debug "pending port %d" (Xeneventchn.to_int port);
                        finally (fun () ->
                                if Some port = eventchn.Event.virq_port then (
                                        let (notify, deaddom) = Domains.cleanup 
xc domains in
@@ -310,7 +314,10 @@ let _ =
                                        if deaddom <> [] || notify then
                                                Connections.fire_spec_watches 
cons "@releaseDomain"
                                )
-                       ) (fun () -> Event.unmask eventchn port);
+                               else
+                                       let c = Connections.find_domain_by_port 
cons port in
+                                       process_domains store cons domains [c]
+                               ) (fun () -> Event.unmask eventchn port)
                and do_if_set fd set fct =
                        if List.mem fd set then
                                fct fd in
@@ -380,7 +387,7 @@ let _ =
                        process_special_fds sfds;
                if List.length cfds > 0 || List.length wset > 0 then
                        process_connection_fds store cons domains cfds wset;
-               process_domains store cons domains
+               process_domains store cons domains mw
                in
 
        while not !quit
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.4

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxx
https://lists.xenproject.org/xen-changelog