From: "Christian König" <ckoenig.leichtzumerken@gmail.com>
To: Michel Lespinasse <walken@google.com>,
"Koenig, Christian" <Christian.Koenig@amd.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>,
Davidlohr Bueso <dbueso@suse.de>,
"peterz@infradead.org" <peterz@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Jerome Glisse <jglisse@redhat.com>,
"amd-gfx@lists.freedesktop.org" <amd-gfx@lists.freedesktop.org>,
Daniel Vetter <daniel@ffwll.ch>,
"Deucher, Alexander" <Alexander.Deucher@amd.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH 03/11] drm/amdgpu: convert amdgpu_vm_it to half closed intervals
Date: Fri, 4 Oct 2019 14:39:40 +0200 [thread overview]
Message-ID: <232710bd-dc54-9d77-6f0f-24a91a28cbf6@gmail.com> (raw)
In-Reply-To: <20191004113628.GA260828@google.com>
Hi Michel,
Am 04.10.19 um 13:36 schrieb Michel Lespinasse:
> On Fri, Oct 04, 2019 at 06:54:54AM +0000, Koenig, Christian wrote:
>> Am 03.10.19 um 22:18 schrieb Davidlohr Bueso:
>>> The amdgpu_vm interval tree really wants [a, b) intervals,
>> NAK, we explicitly do need an [a, b[ interval here.
> Hi Christian,
>
> Just wanted to confirm where you stand on this patch, since I think
> you reconsidered your initial position after first looking at 9/11
> from this series.
>
> I do not know the amdgpu code well, but I think the changes should be
> fine - in struct amdgpu_bo_va_mapping, the "end" field will hold what
> was previously stored in the "last" field, plus one. The expectation
> is that overflows should not be an issue there, as "end" is explicitly
> declared as an uint64, and as the code was previously computing
> "last + 1" in many places.
>
> Does that seem workable to you ?
No, we computed last + 1 in a couple of debug places were it doesn't
hurt us and IIRC we currently cheat a bit because we use pfn instead of
addresses on some other places.
But that is only a leftover from radeon and we need to fix that sooner
or later, cause essentially the physical address space of the device is
really full 64bits, e.g. 0x0-0xffffffffffffffff.
So that only fits into a 64bit int when we use half open/closed
intervals, but would wrap around to zero if we use a closed interval.
I initially thought that the set was changing the interval tree into
always using a closed interval, but that seems to have been a
misunderstanding.
Regards,
Christian.
>
> Thanks,
>
next prev parent reply other threads:[~2019-10-04 12:39 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-03 20:18 [PATCH -next 00/11] lib/interval-tree: move to half closed intervals Davidlohr Bueso
2019-10-03 20:18 ` [PATCH 01/11] mm: introduce vma_interval_tree_foreach_stab() Davidlohr Bueso
2019-10-03 20:18 ` [PATCH 02/11] lib/interval-tree: add an equivalent tree with [a,b) intervals Davidlohr Bueso
2019-10-04 11:02 ` Michel Lespinasse
2019-10-03 20:18 ` [PATCH 03/11] drm/amdgpu: convert amdgpu_vm_it to half closed intervals Davidlohr Bueso
2019-10-04 6:54 ` Koenig, Christian
2019-10-04 11:36 ` Michel Lespinasse
2019-10-04 12:39 ` Christian König [this message]
2019-10-03 20:18 ` [PATCH 04/11] drm: convert drm_mm_interval_tree " Davidlohr Bueso
2019-10-03 20:18 ` [PATCH 05/11] IB/hfi1: convert __mmu_int_rb " Davidlohr Bueso
2019-10-04 11:50 ` Michel Lespinasse
2019-10-04 19:41 ` Davidlohr Bueso
2019-10-03 20:18 ` [PATCH 06/11] IB,usnic: convert usnic_uiom_interval_tree " Davidlohr Bueso
2019-10-03 20:18 ` [PATCH 07/11] vhost: convert vhost_umem_interval_tree " Davidlohr Bueso
2019-10-04 12:10 ` Michel Lespinasse
2019-10-04 19:44 ` Davidlohr Bueso
2019-10-10 5:49 ` Jason Wang
2019-10-03 20:18 ` [PATCH 08/11] mm: convert vma_interval_tree " Davidlohr Bueso
2019-10-03 20:41 ` Matthew Wilcox
2019-10-04 12:30 ` Michel Lespinasse
2019-10-03 20:18 ` [PATCH 09/11] lib/interval-tree: convert interval_tree " Davidlohr Bueso
2019-10-03 22:50 ` kbuild test robot
2019-10-04 6:57 ` Koenig, Christian
2019-10-04 7:20 ` Koenig, Christian
2019-10-08 16:59 ` Davidlohr Bueso
2019-10-03 20:18 ` [PATCH 10/11] lib: drop interval_tree_generic.h Davidlohr Bueso
2019-10-03 20:18 ` [PATCH 11/11] x86/mm, pat: convert pat tree to generic interval tree Davidlohr Bueso
2019-10-07 15:33 ` Ingo Molnar
2019-10-21 23:24 ` Davidlohr Bueso
2019-10-03 20:32 ` [PATCH -next 00/11] lib/interval-tree: move to half closed intervals Matthew Wilcox
2019-10-03 21:10 ` Davidlohr Bueso
2019-10-04 12:43 ` Michel Lespinasse
2019-10-04 0:26 ` Jason Gunthorpe
2019-10-04 2:48 ` Davidlohr Bueso
2019-10-04 13:15 ` Michel Lespinasse
2019-10-04 16:03 ` Matthew Wilcox
2019-10-04 19:35 ` Davidlohr Bueso
2019-10-04 17:45 ` Jason Gunthorpe
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