Date: Fri, 21 Nov 2014 09:07:28 +0000 From: "Robert N. M. Watson" <rwatson@FreeBSD.org> To: Marko Zec <zec@fer.hr> Cc: Craig Rodrigues <rodrigc@freebsd.org>, FreeBSD Net <freebsd-net@freebsd.org>, "Bjoern A.Zeeb" <bz@freebsd.org> Subject: Re: VIMAGE UDP memory leak fix Message-ID: <A8D54927-077E-4FFD-9EBE-1E486621F196@FreeBSD.org> In-Reply-To: <36975BCB-1F45-4128-9FB6-004F07489E53@FreeBSD.org> References: <CAG=rPVehky00X4MuQQ-_Oe5ezWg52ZZrPASAh9GBy7baYv78CA@mail.gmail.com> <20141121002937.4f82daea@x23> <A4D676B3-6C50-47F7-8CFD-50B44FF4BE98@FreeBSD.org> <20141121095847.11601640@x23> <36975BCB-1F45-4128-9FB6-004F07489E53@FreeBSD.org>
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On 21 Nov 2014, at 09:05, Robert N. M. Watson <rwatson@FreeBSD.ORG> = wrote: > To my mind, the only real concern is whether or not you lose access to = resource allocation limits that would previously have been present. On = the whole, we've tried to centralise resource limitations on kernel = memory allocation in UMA, and it would be great if we could find a nice = approach to implementing both per-vimage and per-system allocation = limits. One thing I'd pondered in the past was whether we could move to = a single zone, with its own limits/etc, but also the ability to pass an = optional uma_resourcepool_t that allowed additional limits to be imposed = based on some other criteria -- e.g., vimage membership. That strikes me = as a somewhat complex proposal that would bring new = performance/synchronisation concerns, so isn't necessarily something to = act on. However, the upshot is that, although I do not oppose combining = the zones, we should be aware that we're eliminating a form of resource = partitioning between vimages that we may want to find some other = solution for (ideally, an elegant one). And, to respond to your more general comment: I agree that a decision = about removing the NOFREE flag should be made independently of choices = about devirtualisation. The former probably should be sorted out at this = point, as eliminating NOFREE zones has more general benefits to the = kernel, but it would be nice not to depend on that to resolve other = problems. It could be that a few of us scratching our heads for a few = hours each can resolve whether NOFREE can now be safely removed, in = which case we should do so (and then allow quite a lot of baking time = before it ships in a release). Robert=
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