[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v6 04/14] tools/xenstore: add framework to commit accounting data on success only
Instead of modifying accounting data and undo those modifications in case of an error during further processing, add a framework for collecting the needed changes and commit them only when the whole operation has succeeded. This scheme can reuse large parts of the per transaction accounting. The changed_domain handling can be reused, but the array size of the accounting data should be possible to be different for both use cases. Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx> --- V3: - call acc_commit() earlier (Julien Grall) - add assert() to acc_commit() - use fixed sized acc array in struct changed_domain (Julien Grall) V5: - set conn->in to NULL only locally in acc_commit() (Julien Grall) - define ACC_CHD_N in enum (Julien Grall) --- tools/xenstore/xenstored_core.c | 7 ++++ tools/xenstore/xenstored_core.h | 3 ++ tools/xenstore/xenstored_domain.c | 54 ++++++++++++++++++++++++++++++- tools/xenstore/xenstored_domain.h | 6 +++- 4 files changed, 68 insertions(+), 2 deletions(-) diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c index 3ca68681e3..8392bdec9b 100644 --- a/tools/xenstore/xenstored_core.c +++ b/tools/xenstore/xenstored_core.c @@ -1023,6 +1023,9 @@ static void send_error(struct connection *conn, int error) break; } } + + acc_drop(conn); + send_reply(conn, XS_ERROR, xsd_errors[i].errstring, strlen(xsd_errors[i].errstring) + 1); } @@ -1034,6 +1037,9 @@ void send_reply(struct connection *conn, enum xsd_sockmsg_type type, assert(type != XS_WATCH_EVENT); + /* Commit accounting now, as later errors won't undo any changes. */ + acc_commit(conn); + if ( len > XENSTORE_PAYLOAD_MAX ) { send_error(conn, E2BIG); return; @@ -2195,6 +2201,7 @@ struct connection *new_connection(const struct interface_funcs *funcs) new->is_stalled = false; new->transaction_started = 0; INIT_LIST_HEAD(&new->out_list); + INIT_LIST_HEAD(&new->acc_list); INIT_LIST_HEAD(&new->ref_list); INIT_LIST_HEAD(&new->watches); INIT_LIST_HEAD(&new->transaction_list); diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h index c59b06551f..1f811f38cb 100644 --- a/tools/xenstore/xenstored_core.h +++ b/tools/xenstore/xenstored_core.h @@ -139,6 +139,9 @@ struct connection struct list_head out_list; uint64_t timeout_msec; + /* Not yet committed accounting data (valid if in != NULL). */ + struct list_head acc_list; + /* Referenced requests no longer pending. */ struct list_head ref_list; diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c index 30fb9acec6..e59e40088e 100644 --- a/tools/xenstore/xenstored_domain.c +++ b/tools/xenstore/xenstored_domain.c @@ -100,7 +100,7 @@ struct changed_domain unsigned int domid; /* Accounting data. */ - int acc[ACC_TR_N]; + int acc[ACC_CHD_N]; }; static struct hashtable *domhash; @@ -1070,6 +1070,7 @@ static int domain_acc_add(struct connection *conn, unsigned int domid, enum accitem what, int add, bool no_dom_alloc) { struct domain *d; + struct changed_domain *cd; struct list_head *head; int ret; @@ -1090,6 +1091,22 @@ static int domain_acc_add(struct connection *conn, unsigned int domid, } } + /* Temporary accounting data until final commit? */ + if (conn && conn->in && what < ACC_REQ_N) { + /* Consider transaction local data. */ + ret = 0; + if (conn->transaction && what < ACC_TR_N) { + head = transaction_get_changed_domains( + conn->transaction); + cd = acc_find_changed_domain(head, domid); + if (cd) + ret = cd->acc[what]; + } + ret += acc_add_changed_dom(conn->in, &conn->acc_list, what, + add, domid); + return errno ? -1 : domain_acc_add_valid(d, what, ret); + } + if (conn && conn->transaction && what < ACC_TR_N) { head = transaction_get_changed_domains(conn->transaction); ret = acc_add_changed_dom(conn->transaction, head, what, @@ -1106,6 +1123,41 @@ static int domain_acc_add(struct connection *conn, unsigned int domid, return d->acc[what]; } +void acc_drop(struct connection *conn) +{ + struct changed_domain *cd; + + while ((cd = list_top(&conn->acc_list, struct changed_domain, list))) { + list_del(&cd->list); + talloc_free(cd); + } +} + +void acc_commit(struct connection *conn) +{ + struct changed_domain *cd; + enum accitem what; + struct buffered_data *in = conn->in; + + /* + * Make sure domain_acc_add() below can't add additional data to + * to be committed accounting records. + */ + conn->in = NULL; + + while ((cd = list_top(&conn->acc_list, struct changed_domain, list))) { + list_del(&cd->list); + for (what = 0; what < ACC_REQ_N; what++) + if (cd->acc[what]) + domain_acc_add(conn, cd->domid, what, + cd->acc[what], true); + + talloc_free(cd); + } + + conn->in = in; +} + int domain_nbentry_inc(struct connection *conn, unsigned int domid) { return (domain_acc_add(conn, domid, ACC_NODES, 1, false) < 0) diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h index 9d05eb01da..e40657216b 100644 --- a/tools/xenstore/xenstored_domain.h +++ b/tools/xenstore/xenstored_domain.h @@ -25,8 +25,10 @@ * a per transaction array. */ enum accitem { - ACC_NODES, + ACC_REQ_N, /* Number of elements per request. */ + ACC_NODES = ACC_REQ_N, ACC_TR_N, /* Number of elements per transaction. */ + ACC_CHD_N = ACC_TR_N, /* max(ACC_REQ_N, ACC_TR_N), for changed dom. */ ACC_N = ACC_TR_N, /* Number of elements per domain. */ }; @@ -113,6 +115,8 @@ int domain_get_quota(const void *ctx, struct connection *conn, * If "update" is true, "chk_quota" is ignored. */ int acc_fix_domains(struct list_head *head, bool chk_quota, bool update); +void acc_drop(struct connection *conn); +void acc_commit(struct connection *conn); /* Write rate limiting */ -- 2.35.3
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