From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Michael Kelley <mikelley@microsoft.com>,
"m.maya.nakamura" <m.maya.nakamura@gmail.com>
Cc: "x86\@kernel.org" <x86@kernel.org>,
"linux-hyperv\@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
KY Srinivasan <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
"sashal\@kernel.org" <sashal@kernel.org>
Subject: RE: [PATCH v2 4/5] HID: hv: Remove dependencies on PAGE_SIZE for ring buffer
Date: Fri, 14 Jun 2019 09:53:11 +0200 [thread overview]
Message-ID: <87ftoc7gd4.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <BL0PR2101MB134877ED5DCB9F23033C92D9D7EF0@BL0PR2101MB1348.namprd21.prod.outlook.com>
Michael Kelley <mikelley@microsoft.com> writes:
> From: Vitaly Kuznetsov <vkuznets@redhat.com> Sent: Wednesday, June 12, 2019 3:40 AM
>> Maya Nakamura <m.maya.nakamura@gmail.com> writes:
>>
>> > Define the ring buffer size as a constant expression because it should
>> > not depend on the guest page size.
>> >
>> > Signed-off-by: Maya Nakamura <m.maya.nakamura@gmail.com>
>> > ---
>> > drivers/hid/hid-hyperv.c | 4 ++--
>> > 1 file changed, 2 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/drivers/hid/hid-hyperv.c b/drivers/hid/hid-hyperv.c
>> > index d3311d714d35..e8b154fa38e2 100644
>> > --- a/drivers/hid/hid-hyperv.c
>> > +++ b/drivers/hid/hid-hyperv.c
>> > @@ -112,8 +112,8 @@ struct synthhid_input_report {
>> >
>> > #pragma pack(pop)
>> >
>> > -#define INPUTVSC_SEND_RING_BUFFER_SIZE (10*PAGE_SIZE)
>> > -#define INPUTVSC_RECV_RING_BUFFER_SIZE (10*PAGE_SIZE)
>> > +#define INPUTVSC_SEND_RING_BUFFER_SIZE (40 * 1024)
>> > +#define INPUTVSC_RECV_RING_BUFFER_SIZE (40 * 1024)
>> >
>>
>> My understanding is that this size is pretty arbitrary and as I see you
>> use it for hyperv-keyboard.c as well. It may make sense to have a
>> define, something like HYPERV_STD_RINGBUFFER_SIZE.
>
> Yes, the size is pretty arbitrary because it hasn't been important enough
> from a memory consumption or performance standpoint to run experiments
> to see if a smaller value could be used. That said, I would not want to
> link these two devices (keyboard and mouse) by using a shared ring buffer
> size definition. Logically, the ring buffer sizes are independent of each other,
> and using a common #define implies that they are somehow linked.
Ok, makes sense, let's keep them separate.
--
Vitaly
next prev parent reply other threads:[~2019-06-14 7:53 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-06 8:00 [PATCH v2 0/5] hv: Remove dependencies on guest page size Maya Nakamura
2019-06-06 8:03 ` [PATCH v2 1/5] x86: hv: hyperv-tlfs.h: Create and use Hyper-V page definitions Maya Nakamura
2019-06-12 10:36 ` Vitaly Kuznetsov
2019-06-06 8:05 ` [PATCH v2 2/5] x86: hv: hv_init.c: Add functions to allocate/deallocate page for Hyper-V Maya Nakamura
2019-06-12 10:36 ` Vitaly Kuznetsov
2019-06-17 3:59 ` Maya Nakamura
2019-06-06 8:06 ` [PATCH v2 3/5] hv: vmbus: Replace page definition with Hyper-V specific one Maya Nakamura
2019-06-12 10:38 ` Vitaly Kuznetsov
2019-06-06 8:07 ` [PATCH v2 4/5] HID: hv: Remove dependencies on PAGE_SIZE for ring buffer Maya Nakamura
2019-06-12 10:40 ` Vitaly Kuznetsov
[not found] ` <BL0PR2101MB134877ED5DCB9F23033C92D9D7EF0@BL0PR2101MB1348.namprd21.prod.outlook.com>
2019-06-14 7:53 ` Vitaly Kuznetsov [this message]
2019-06-06 8:09 ` [PATCH v2 5/5] Input: " Maya Nakamura
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