From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>, Keir Fraser <keir@xen.org>
Subject: Re: [PATCH 1/2] common: make hypercall preemption checks consistent
Date: Tue, 4 Mar 2014 11:29:42 +0000 [thread overview]
Message-ID: <5315B926.6030306@citrix.com> (raw)
In-Reply-To: <5315C6160200007800120CF3@nat28.tlf.novell.com>
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On 04/03/14 11:24, Jan Beulich wrote:
> - never preempt on the first iteration (ensure forward progress)
> - do cheap checks first
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
>
> --- a/xen/common/memory.c
> +++ b/xen/common/memory.c
> @@ -63,7 +63,7 @@ static void increase_reservation(struct
>
> for ( i = a->nr_done; i < a->nr_extents; i++ )
> {
> - if ( hypercall_preempt_check() )
> + if ( i != a->nr_done && hypercall_preempt_check() )
> {
> a->preempted = 1;
> goto out;
> @@ -109,7 +109,7 @@ static void populate_physmap(struct memo
>
> for ( i = a->nr_done; i < a->nr_extents; i++ )
> {
> - if ( hypercall_preempt_check() )
> + if ( i != a->nr_done && hypercall_preempt_check() )
> {
> a->preempted = 1;
> goto out;
> @@ -268,7 +268,7 @@ static void decrease_reservation(struct
>
> for ( i = a->nr_done; i < a->nr_extents; i++ )
> {
> - if ( hypercall_preempt_check() && i != a->nr_done )
> + if ( i != a->nr_done && hypercall_preempt_check() )
> {
> a->preempted = 1;
> goto out;
> @@ -398,7 +398,8 @@ static long memory_exchange(XEN_GUEST_HA
> i < (exch.in.nr_extents >> in_chunk_order);
> i++ )
> {
> - if ( hypercall_preempt_check() )
> + if ( i != (exch.nr_exchanged >> in_chunk_order) &&
> + hypercall_preempt_check() )
> {
> exch.nr_exchanged = i << in_chunk_order;
> rcu_unlock_domain(d);
> --- a/xen/common/multicall.c
> +++ b/xen/common/multicall.c
> @@ -52,7 +52,7 @@ do_multicall(
>
> for ( i = 0; !rc && i < nr_calls; i++ )
> {
> - if ( hypercall_preempt_check() )
> + if ( i && hypercall_preempt_check() )
> goto preempted;
>
> if ( unlikely(__copy_from_guest(&mcs->call, call_list, 1)) )
> --- a/xen/drivers/char/console.c
> +++ b/xen/drivers/char/console.c
> @@ -375,12 +375,12 @@ static DECLARE_SOFTIRQ_TASKLET(notify_do
> static long guest_console_write(XEN_GUEST_HANDLE_PARAM(char) buffer, int count)
> {
> char kbuf[128];
> - int kcount;
> + int kcount = 0;
> struct domain *cd = current->domain;
>
> while ( count > 0 )
> {
> - if ( hypercall_preempt_check() )
> + if ( kcount && hypercall_preempt_check() )
> return hypercall_create_continuation(
> __HYPERVISOR_console_io, "iih",
> CONSOLEIO_write, count, buffer);
>
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
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next prev parent reply other threads:[~2014-03-04 11:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-04 11:21 [PATCH 0/2] make hypercall preemption checks consistent Jan Beulich
2014-03-04 11:24 ` [PATCH 1/2] common: " Jan Beulich
2014-03-04 11:29 ` Andrew Cooper [this message]
2014-03-04 11:26 ` [PATCH 2/2] x86: " Jan Beulich
2014-03-04 11:35 ` Andrew Cooper
2014-03-04 11:30 ` [PATCH 0/2] " Jan Beulich
2014-03-11 11:38 ` Ian Campbell
2014-03-04 11:46 ` Tim Deegan
2014-03-04 11:52 ` Andrew Cooper
2014-03-04 12:00 ` Jan Beulich
2014-03-04 12:10 ` David Vrabel
2014-03-04 13:06 ` Jan Beulich
2014-03-04 14:07 ` David Vrabel
2014-03-12 9:35 ` Ping: " Jan Beulich
2014-03-13 10:26 ` Keir Fraser
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