[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/6] xenbus: prepare data structures and parameter for xenwatch multithreading
On 14/09/18 09:34, Dongli Zhang wrote: > This is the 1st patch of a (6-patch) patch set. > > This patch set of six patches introduces xenwatch multithreading (or > multithreaded xenwatch, abbreviated as 'mtwatch') to dom0 kernel. In > addition to the existing single xenwatch thread, each domU has its own > kernel thread ([xen-mtwatch-<domid>]) to process its xenwatch event. > > A kernel parameter 'xen_mtwatch' is introduced to control whether the > feature is enabled or not during dom0 kernel boot. The feature is disabled > by default if 'xen_mtwatch' is not set in grub. In addition, this patch > also introduces the data structures to maintain the status of each per-domU > xenwatch thread. The status of each xenwatch thread (except the default > one) is maintained by a mtwatch domain. > > The feature is available only on dom0. > > Signed-off-by: Dongli Zhang <dongli.zhang@xxxxxxxxxx> > --- > Documentation/admin-guide/kernel-parameters.txt | 3 ++ > drivers/xen/xenbus/xenbus_xs.c | 31 ++++++++++++ > include/xen/xenbus.h | 65 > +++++++++++++++++++++++++ > 3 files changed, 99 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt > b/Documentation/admin-guide/kernel-parameters.txt > index 64a3bf5..fc295ef 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -4992,6 +4992,9 @@ > the unplug protocol > never -- do not unplug even if version check succeeds > > + xen_mtwatch [KNL,XEN] > + Enables the multithreaded xenwatch (mtwatch). > + > xen_nopvspin [X86,XEN] > Disables the ticketlock slowpath using Xen PV > optimizations. > diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c > index 49a3874..3f137d2 100644 > --- a/drivers/xen/xenbus/xenbus_xs.c > +++ b/drivers/xen/xenbus/xenbus_xs.c > @@ -95,6 +95,19 @@ static pid_t xenwatch_pid; > static DEFINE_MUTEX(xenwatch_mutex); > static DECLARE_WAIT_QUEUE_HEAD(watch_events_waitq); > > +bool xen_mtwatch; > +EXPORT_SYMBOL_GPL(xen_mtwatch); > + > +struct mtwatch_info *mtwatch_info; > + > +static bool param_xen_mtwatch; > +static __init int xen_parse_mtwatch(char *arg) > +{ > + param_xen_mtwatch = true; > + return 0; > +} > +early_param("xen_mtwatch", xen_parse_mtwatch); Add a Kconfig item to set the default when building the kernel? We can start with default "off", but later we might want to enable this feature as the default. > + > static void xs_suspend_enter(void) > { > spin_lock(&xs_state_lock); > @@ -929,6 +942,24 @@ int xs_init(void) > if (err) > return err; > > + if (xen_initial_domain() && param_xen_mtwatch) { Wouldn't it be better to drop the test for xen_initial_domain() and do this initialization only when a caller (backend) is requesting the multithread mode? This would avoid wasting memory in case it isn't going top be used and - more important - would support driver domains. Juergen _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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