> -----Original Message----- > From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx] > Sent: Thursday, January 29, 2015 21:31 PM > To: Dexuan Cui > Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; driverdev- > devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx; apw@xxxxxxxxxxxxx; > jasowang@xxxxxxxxxx; KY Srinivasan; Haiyang Zhang > Subject: Re: [PATCH 2/3] hv: vmbus_post_msg: retry the hypercall on > HV_STATUS_INVALID_CONNECTION_ID > > Dexuan Cui <decui@xxxxxxxxxxxxx> writes: > > > I got the hypercall error code on Hyper-V 2008 R2 when keeping running > > "rmmod hv_netvsc; modprobe hv_netvsc; rmmod hv_utils; modprobe hv_utils" > > in a Linux guest. > > > > Without the patch, the driver can occasionally fail to load. > > > > CC: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> > > Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx> > > --- > > arch/x86/include/uapi/asm/hyperv.h | 1 + > > drivers/hv/connection.c | 9 +++++++++ > > 2 files changed, 10 insertions(+) > > > > diff --git a/arch/x86/include/uapi/asm/hyperv.h > b/arch/x86/include/uapi/asm/hyperv.h > > index 90c458e..b9daffb 100644 > > --- a/arch/x86/include/uapi/asm/hyperv.h > > +++ b/arch/x86/include/uapi/asm/hyperv.h > > @@ -225,6 +225,7 @@ > > #define HV_STATUS_INVALID_HYPERCALL_CODE 2 > > #define HV_STATUS_INVALID_HYPERCALL_INPUT 3 > > #define HV_STATUS_INVALID_ALIGNMENT 4 > > +#define HV_STATUS_INVALID_CONNECTION_ID 18 > > #define HV_STATUS_INSUFFICIENT_BUFFERS 19 > > The gap beween 4 and 18 tells me there are other codes here ;-) Are they > all 'permanent failures'? It looks we only need to care about these error codes here. BTW, you can get all the hypercall error codes in the top level functional spec: http://blogs.msdn.com/b/virtual_pc_guy/archive/2014/02/17/updated-hypervisor-top-level-functional-specification.aspx For this hypercall (0x005c), see "14.9.7 HvPostMessage". > > > > typedef struct _HV_REFERENCE_TSC_PAGE { > > diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c > > index c4acd1c..8bd05f3 100644 > > --- a/drivers/hv/connection.c > > +++ b/drivers/hv/connection.c > > @@ -440,6 +440,15 @@ int vmbus_post_msg(void *buffer, size_t buflen) > > ret = hv_post_message(conn_id, 1, buffer, buflen); > > > > switch (ret) { > > + case HV_STATUS_INVALID_CONNECTION_ID: > > + /* > > + * We could get this if we send messages too > > + * frequently or the host is under low resource > > + * conditions: let's wait 1 more second before > > + * retrying the hypercall. > > + */ > > + msleep(1000); > > + break; > > In case it is our last try (No. 10) we will return '18' from the > function. I suggest we set ret = -ENOMEM here as well. Thanks for the suggestion! I think it would be better to add this to the case HV_STATUS_INVALID_CONNECTION_ID: ret = -EAGAIN; ? > > case HV_STATUS_INSUFFICIENT_BUFFERS: > > ret = -ENOMEM; > > Or should we treat these two equally? There is a smaller (100ms) sleep > between tries already, we can consider changing it instead. > > > case -ENOMEM: > > -- > Vitaly In my experiments, in the HV_STATUS_INVALID_CONNECTION_ID case, waiting 100ms is not enough sometimes, so I'd like to wait more time. I agree with you both cases can wait 1000ms. I'll update my patch. BTW, the " case -ENOMEM:" is not reachable(the hypervisor itself doesn't return -ENOMEM), I think. I can remove it. Thanks, -- Dexuan _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
