diff options
Diffstat (limited to '0048-tools-xenstore-reduce-number-of-watch-events.patch')
| -rw-r--r-- | 0048-tools-xenstore-reduce-number-of-watch-events.patch | 201 |
1 files changed, 0 insertions, 201 deletions
diff --git a/0048-tools-xenstore-reduce-number-of-watch-events.patch b/0048-tools-xenstore-reduce-number-of-watch-events.patch deleted file mode 100644 index 3a080fb..0000000 --- a/0048-tools-xenstore-reduce-number-of-watch-events.patch +++ /dev/null @@ -1,201 +0,0 @@ -From e26d6f4d1b389b859fb5a6570421e80e0213f92b Mon Sep 17 00:00:00 2001 -From: Juergen Gross <jgross@suse.com> -Date: Tue, 13 Sep 2022 07:35:07 +0200 -Subject: [PATCH 48/87] tools/xenstore: reduce number of watch events - -When removing a watched node outside of a transaction, two watch events -are being produced instead of just a single one. - -When finalizing a transaction watch events can be generated for each -node which is being modified, even if outside a transaction such -modifications might not have resulted in a watch event. - -This happens e.g.: - -- for nodes which are only modified due to added/removed child entries -- for nodes being removed or created implicitly (e.g. creation of a/b/c - is implicitly creating a/b, resulting in watch events for a, a/b and - a/b/c instead of a/b/c only) - -Avoid these additional watch events, in order to reduce the needed -memory inside Xenstore for queueing them. - -This is being achieved by adding event flags to struct accessed_node -specifying whether an event should be triggered, and whether it should -be an exact match of the modified path. Both flags can be set from -fire_watches() instead of implying them only. - -This is part of XSA-326. - -Signed-off-by: Juergen Gross <jgross@suse.com> -Reviewed-by: Julien Grall <jgrall@amazon.com> -(cherry picked from commit 3a96013a3e17baa07410b1b9776225d1d9a74297) ---- - tools/xenstore/xenstored_core.c | 19 ++++++------ - tools/xenstore/xenstored_transaction.c | 41 +++++++++++++++++++++----- - tools/xenstore/xenstored_transaction.h | 3 ++ - tools/xenstore/xenstored_watch.c | 7 +++-- - 4 files changed, 51 insertions(+), 19 deletions(-) - -diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c -index 527a1ebdeded..bf2243873901 100644 ---- a/tools/xenstore/xenstored_core.c -+++ b/tools/xenstore/xenstored_core.c -@@ -1295,7 +1295,7 @@ static void delete_child(struct connection *conn, - } - - static int delete_node(struct connection *conn, const void *ctx, -- struct node *parent, struct node *node) -+ struct node *parent, struct node *node, bool watch_exact) - { - char *name; - -@@ -1307,7 +1307,7 @@ static int delete_node(struct connection *conn, const void *ctx, - node->children); - child = name ? read_node(conn, node, name) : NULL; - if (child) { -- if (delete_node(conn, ctx, node, child)) -+ if (delete_node(conn, ctx, node, child, true)) - return errno; - } else { - trace("delete_node: Error deleting child '%s/%s'!\n", -@@ -1319,7 +1319,12 @@ static int delete_node(struct connection *conn, const void *ctx, - talloc_free(name); - } - -- fire_watches(conn, ctx, node->name, node, true, NULL); -+ /* -+ * Fire the watches now, when we can still see the node permissions. -+ * This fine as we are single threaded and the next possible read will -+ * be handled only after the node has been really removed. -+ */ -+ fire_watches(conn, ctx, node->name, node, watch_exact, NULL); - delete_node_single(conn, node); - delete_child(conn, parent, basename(node->name)); - talloc_free(node); -@@ -1345,13 +1350,7 @@ static int _rm(struct connection *conn, const void *ctx, struct node *node, - return (errno == ENOMEM) ? ENOMEM : EINVAL; - node->parent = parent; - -- /* -- * Fire the watches now, when we can still see the node permissions. -- * This fine as we are single threaded and the next possible read will -- * be handled only after the node has been really removed. -- */ -- fire_watches(conn, ctx, name, node, false, NULL); -- return delete_node(conn, ctx, parent, node); -+ return delete_node(conn, ctx, parent, node, false); - } - - -diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c -index faf6c930e42a..54432907fc76 100644 ---- a/tools/xenstore/xenstored_transaction.c -+++ b/tools/xenstore/xenstored_transaction.c -@@ -130,6 +130,10 @@ struct accessed_node - - /* Transaction node in data base? */ - bool ta_node; -+ -+ /* Watch event flags. */ -+ bool fire_watch; -+ bool watch_exact; - }; - - struct changed_domain -@@ -323,6 +327,29 @@ err: - return ret; - } - -+/* -+ * A watch event should be fired for a node modified inside a transaction. -+ * Set the corresponding information. A non-exact event is replacing an exact -+ * one, but not the other way round. -+ */ -+void queue_watches(struct connection *conn, const char *name, bool watch_exact) -+{ -+ struct accessed_node *i; -+ -+ i = find_accessed_node(conn->transaction, name); -+ if (!i) { -+ conn->transaction->fail = true; -+ return; -+ } -+ -+ if (!i->fire_watch) { -+ i->fire_watch = true; -+ i->watch_exact = watch_exact; -+ } else if (!watch_exact) { -+ i->watch_exact = false; -+ } -+} -+ - /* - * Finalize transaction: - * Walk through accessed nodes and check generation against global data. -@@ -377,15 +404,15 @@ static int finalize_transaction(struct connection *conn, - ret = tdb_store(tdb_ctx, key, data, - TDB_REPLACE); - talloc_free(data.dptr); -- if (ret) -- goto err; -- fire_watches(conn, trans, i->node, NULL, false, -- i->perms.p ? &i->perms : NULL); - } else { -- fire_watches(conn, trans, i->node, NULL, false, -+ ret = tdb_delete(tdb_ctx, key); -+ } -+ if (ret) -+ goto err; -+ if (i->fire_watch) { -+ fire_watches(conn, trans, i->node, NULL, -+ i->watch_exact, - i->perms.p ? &i->perms : NULL); -- if (tdb_delete(tdb_ctx, key)) -- goto err; - } - } - -diff --git a/tools/xenstore/xenstored_transaction.h b/tools/xenstore/xenstored_transaction.h -index 14062730e3c9..0093cac807e3 100644 ---- a/tools/xenstore/xenstored_transaction.h -+++ b/tools/xenstore/xenstored_transaction.h -@@ -42,6 +42,9 @@ void transaction_entry_dec(struct transaction *trans, unsigned int domid); - int access_node(struct connection *conn, struct node *node, - enum node_access_type type, TDB_DATA *key); - -+/* Queue watches for a modified node. */ -+void queue_watches(struct connection *conn, const char *name, bool watch_exact); -+ - /* Prepend the transaction to name if appropriate. */ - int transaction_prepend(struct connection *conn, const char *name, - TDB_DATA *key); -diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c -index 99a2c266b28a..205d9d8ea116 100644 ---- a/tools/xenstore/xenstored_watch.c -+++ b/tools/xenstore/xenstored_watch.c -@@ -29,6 +29,7 @@ - #include "xenstore_lib.h" - #include "utils.h" - #include "xenstored_domain.h" -+#include "xenstored_transaction.h" - - extern int quota_nb_watch_per_domain; - -@@ -143,9 +144,11 @@ void fire_watches(struct connection *conn, const void *ctx, const char *name, - struct connection *i; - struct watch *watch; - -- /* During transactions, don't fire watches. */ -- if (conn && conn->transaction) -+ /* During transactions, don't fire watches, but queue them. */ -+ if (conn && conn->transaction) { -+ queue_watches(conn, name, exact); - return; -+ } - - /* Create an event for each watch. */ - list_for_each_entry(i, &connections, list) { --- -2.37.4 - |