RE: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread KY Srinivasan
; jasow...@redhat.com > Subject: Re: [PATCH 2/5] hv: add helpers to handle hv_util device state > > On Mon, Sep 21, 2015 at 04:34:56PM +, KY Srinivasan wrote: > > > > > > > -Original Message- > > > From: Olaf Hering [mailto:o...@aepfle.de] > >

RE: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread KY Srinivasan
hat.com > Subject: Re: [PATCH 2/5] hv: add helpers to handle hv_util device state > > On Mon, Sep 21, Vitaly Kuznetsov wrote: > > > I'd like to see a trace from the hang, it is not obvious to me how it > > happened and what caused it. (or if you have such hang sce

Re: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread Greg KH
r.kernel.org; de...@linuxdriverproject.org; > > a...@canonical.com; vkuzn...@redhat.com; jasow...@redhat.com > > Subject: Re: [PATCH 2/5] hv: add helpers to handle hv_util device state > > > > On Sun, Sep 20, Greg KH wrote: > > > > > Just use a lock, that's what

RE: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread KY Srinivasan
hat.com > Subject: Re: [PATCH 2/5] hv: add helpers to handle hv_util device state > > On Sun, Sep 20, Greg KH wrote: > > > Just use a lock, that's what it is there for. > > How would that help? It might help because it enforces ordering. But > that requires that all three ut

Re: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread Vitaly Kuznetsov
Olaf Hering writes: > On Mon, Sep 21, Vitaly Kuznetsov wrote: > >> I'd like to see a trace from the hang, it is not obvious to me how it >> happened and what caused it. (or if you have such hang scenario in your >> head, can you please reveal it?) > > There is no trace. I think

Re: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread Olaf Hering
On Mon, Sep 21, Vitaly Kuznetsov wrote: > I'd like to see a trace from the hang, it is not obvious to me how it > happened and what caused it. (or if you have such hang scenario in your > head, can you please reveal it?) There is no trace. I think fcopy_respond_to_host notifies the host, which

Re: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread Vitaly Kuznetsov
Olaf Hering writes: > On Sun, Sep 20, Greg KH wrote: > >> Just use a lock, that's what it is there for. > > How would that help? It might help because it enforces ordering. But > that requires that all three utils get refactored to deal with the > introduced locking. I will let KY comment on

Re: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread Olaf Hering
On Sun, Sep 20, Greg KH wrote: > Just use a lock, that's what it is there for. How would that help? It might help because it enforces ordering. But that requires that all three utils get refactored to deal with the introduced locking. I will let KY comment on this. The issue I see with fcopy is

Re: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread Olaf Hering
On Sun, Sep 20, Greg KH wrote: > Just use a lock, that's what it is there for. How would that help? It might help because it enforces ordering. But that requires that all three utils get refactored to deal with the introduced locking. I will let KY comment on this. The issue I see with fcopy is

Re: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread Vitaly Kuznetsov
Olaf Hering writes: > On Sun, Sep 20, Greg KH wrote: > >> Just use a lock, that's what it is there for. > > How would that help? It might help because it enforces ordering. But > that requires that all three utils get refactored to deal with the > introduced locking. I will let

Re: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread Vitaly Kuznetsov
Olaf Hering writes: > On Mon, Sep 21, Vitaly Kuznetsov wrote: > >> I'd like to see a trace from the hang, it is not obvious to me how it >> happened and what caused it. (or if you have such hang scenario in your >> head, can you please reveal it?) > > There is no trace. I think

RE: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread KY Srinivasan
g; > a...@canonical.com; vkuzn...@redhat.com; jasow...@redhat.com > Subject: Re: [PATCH 2/5] hv: add helpers to handle hv_util device state > > On Sun, Sep 20, Greg KH wrote: > > > Just use a lock, that's what it is there for. > > How would that help? It might help because

Re: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread Greg KH
...@linuxfoundation.org> > > Cc: linux-kernel@vger.kernel.org; de...@linuxdriverproject.org; > > a...@canonical.com; vkuzn...@redhat.com; jasow...@redhat.com > > Subject: Re: [PATCH 2/5] hv: add helpers to handle hv_util device state > > > > On Sun, Sep 20, Greg K

RE: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread KY Srinivasan
org; a...@canonical.com; vkuzn...@redhat.com; > jasow...@redhat.com > Subject: Re: [PATCH 2/5] hv: add helpers to handle hv_util device state > > On Mon, Sep 21, 2015 at 04:34:56PM +, KY Srinivasan wrote: > > > > > > > -Original Message- > > > From: Ol

Re: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread Olaf Hering
On Mon, Sep 21, Vitaly Kuznetsov wrote: > I'd like to see a trace from the hang, it is not obvious to me how it > happened and what caused it. (or if you have such hang scenario in your > head, can you please reveal it?) There is no trace. I think fcopy_respond_to_host notifies the host, which

RE: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-21 Thread KY Srinivasan
; linux-kernel@vger.kernel.org; > de...@linuxdriverproject.org; a...@canonical.com; jasow...@redhat.com > Subject: Re: [PATCH 2/5] hv: add helpers to handle hv_util device state > > On Mon, Sep 21, Vitaly Kuznetsov wrote: > > > I'd like to see a trace from the hang, it is not obvious to m

Re: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-20 Thread Greg KH
On Tue, Sep 15, 2015 at 05:37:51PM -0700, K. Y. Srinivasan wrote: > From: Olaf Hering > > The callbacks in kvp, vss and fcopy code are called both from the main thread > as well as from interrupt context. If a state change is done by the main > thread it is not immediately seen by the interrupt.

Re: [PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-20 Thread Greg KH
On Tue, Sep 15, 2015 at 05:37:51PM -0700, K. Y. Srinivasan wrote: > From: Olaf Hering > > The callbacks in kvp, vss and fcopy code are called both from the main thread > as well as from interrupt context. If a state change is done by the main > thread it is not immediately seen

[PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-15 Thread K. Y. Srinivasan
From: Olaf Hering The callbacks in kvp, vss and fcopy code are called both from the main thread as well as from interrupt context. If a state change is done by the main thread it is not immediately seen by the interrupt. As a result the state machine gets out of sync. Force propagation of state

[PATCH 2/5] hv: add helpers to handle hv_util device state

2015-09-15 Thread K. Y. Srinivasan
From: Olaf Hering The callbacks in kvp, vss and fcopy code are called both from the main thread as well as from interrupt context. If a state change is done by the main thread it is not immediately seen by the interrupt. As a result the state machine gets out of sync. Force