Responses inline.
Internal Use - Confidential > -----Original Message----- > From: fengchengwen <[email protected]> > Sent: Wednesday, November 12, 2025 11:23 PM > To: Bathija, Pravin <[email protected]>; [email protected] > Cc: [email protected] > Subject: Re: [PATCH v3 5/5] vhost_user: Increase number of memory regions > > > [EXTERNAL EMAIL] > > On 11/13/2025 10:13 AM, Bathija, Pravin wrote: > > Answers inline > > > > > > Internal Use - Confidential > >> -----Original Message----- > >> From: fengchengwen <[email protected]> > >> Sent: Tuesday, November 11, 2025 5:26 PM > >> To: Bathija, Pravin <[email protected]>; [email protected] > >> Cc: [email protected] > >> Subject: Re: [PATCH v3 5/5] vhost_user: Increase number of memory > >> regions > >> > >> > >> [EXTERNAL EMAIL] > >> > >> On 11/11/2025 7:34 PM, Bathija, Pravin wrote: > >>> Responses inline. > >>> > >>> > >>> Internal Use - Confidential > >>>> -----Original Message----- > >>>> From: fengchengwen <[email protected]> > >>>> Sent: Tuesday, November 4, 2025 12:12 AM > >>>> To: Bathija, Pravin <[email protected]>; [email protected] > >>>> Cc: [email protected] > >>>> Subject: Re: [PATCH v3 5/5] vhost_user: Increase number of memory > >>>> regions > >>>> > >>>> > >>>> [EXTERNAL EMAIL] > >>>> > >>>> On 11/4/2025 12:21 PM, Pravin M Bathija wrote: > >>>>> In this patch the number of memory regions are increased from > >>>>> 8 to 128. When a vhost-user front-end such as qemu or libblkio > >>>>> queries the back-end such as dpdk with the message, get max number > >>>>> of memory slots, the back-end replies with this number 128 instead > >>>>> of the previously defined 8. The back-end also allocates that many > >>>>> slots in the memory table where regions are added/removed as > >>>>> requested by the vhost-user front-end. This also helps the vhost- > >>>>> user front-end to limit the number of memory regions when sending > >>>>> the set mem table message ar adding memory regions. > >>>>> > >>>>> Signed-off-by: Pravin M Bathija <[email protected]> > >>>>> --- > >>>>> lib/vhost/vhost_user.h | 2 +- > >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>>>> > >>>>> diff --git a/lib/vhost/vhost_user.h b/lib/vhost/vhost_user.h index > >>>>> 5a0e747b58..c6ad5b76d6 100644 > >>>>> --- a/lib/vhost/vhost_user.h > >>>>> +++ b/lib/vhost/vhost_user.h > >>>>> @@ -11,7 +11,7 @@ > >>>>> > >>>>> /* refer to hw/virtio/vhost-user.c */ > >>>>> > >>>>> -#define VHOST_MEMORY_MAX_NREGIONS 8 > >>>>> +#define VHOST_MEMORY_MAX_NREGIONS 128 > >>>> > >>>> The address translation may increase a lot if the real region is 128. > >>>> Maybe we should add another patch to optimize it. > >>> > >>> Could you please share more thoughts on this ? Are you concerned > >>> about > >> the number of addresses and translation table bloat ? What > >> optimization are you suggesting ? > >> > >> Because each memory region is independent and does not overlap, maybe > >> we could use binary search to optimize it. > > > > From what I gather, both of your latest comments, for patches 4 and 5 are > related to performance impact because of 128 memory regions. My thoughts > on this are, I will work on an algorithm to optimize as you suggested. > Meanwhile we could approve patches 1-4. The rest of the implementation does > not need 128 memory regions. The existing 8 regions are fine. I put in this > change as I felt it makes the system scale more and was also suggested by > Maxime. I think patches 1-4 stand by themselves and have been thoroughly > tested. Please let me know your thoughts on this. > > I am OK for this. Thank you for the quick response. I have just submitted v5 of the patchset where I removed the patch which increases the memory regions to 128. Please Ack and help merge to mainline. > > > > >> > >>> > >>>> > >>>>> > >>>>> #define VHOST_USER_NET_SUPPORTED_FEATURES \ > >>>>> (VIRTIO_NET_SUPPORTED_FEATURES | \ > >>> > >>> > > > >
