From: "Thomas Hellström" <thomas.hellstrom@linux.intel.com> To: "Christian König" <christian.koenig@amd.com>, "Matthew Auld" <matthew.william.auld@gmail.com> Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>, ML dri-devel <dri-devel@lists.freedesktop.org> Subject: Re: [Intel-gfx] [PATCH v3 06/12] drm/ttm: Add a generic TTM memcpy move for page-based iomem Date: Wed, 26 May 2021 12:57:10 +0200 [thread overview] Message-ID: <fbbb896e7e886e4d41b3a319c6aa7c5bb2e8ad4e.camel@linux.intel.com> (raw) In-Reply-To: <9f8fe3af-6d49-f652-70bc-36a27007d821@amd.com> On Wed, 2021-05-26 at 12:45 +0200, Christian König wrote: > Am 26.05.21 um 09:39 schrieb Thomas Hellström: > > [SNIP] > > > > I think the long term goal is to use memremap all over the > > > > place, to > > > > just not have to bother with the __iomem annotation. But to do > > > > that io- > > > > mapping.h needs to support memremap. But for now we need to be > > > > strict > > > > about __iomem unless we're in arch specific code. That's why > > > > that > > > > dma_buf_map thing was created, but TTM memcpy was never fully > > > > adapted. > > > > > > I don't think that this will work. __iomem annotation is there > > > because we have architectures where you need to use special CPU > > > instructions for iomem access. > > > > > > That won't go away just because we use memremap(). > > > > That's true, but can we ever support those with TTM, given that we > > allow user-space mmaping that transparently may change to an iomap? > > Given that, and what's written here > > > > > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flwn.net%2FArticles%2F653585%2F&data=04%7C01%7Cchristian.koenig%40amd.com%7C1cdcfe9d20e740308c9e08d92019785b%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637576116034492654%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=e2BFGQJcElwVxrvHcnALDWscHN7ernLekGvXHqWBcwY%3D&reserved=0 > > > > > > > > To me it sounds like if an architecture can't support memremap, we > > can't support it with TTM either. > > That was also my argument, but this is unfortunately not true. > > We already have architectures where the __iomem approach is mandatory > for kernel mappings, but work fine for userspace (don't ask me how > that > works, idk). Ugh. :/ > > That's the reason why we had to fix the UVD firmware upload in the > kernel: > > commit ba0b2275a6781b2f3919d931d63329b5548f6d5f > Author: Christian König <christian.koenig@amd.com> > Date: Tue Aug 23 11:00:17 2016 +0200 > > drm/amdgpu: use memcpy_to/fromio for UVD fw upload > > > > > In any case for this particular patch, to avoid potential > > regressions, > > OK if I just add an ioremap() in case the memremap fails? > > Well because of the issues outlined above I would actually prefer if > we > can keep the __iomem annotation around. Well, we'd do that. Since we use the dma_buf_map unconditionally. So what would happen in the above case, would be: - memremap would fail. (Otherwise I'd be terribly confused) - we retry with ioremap and the dma-buf-map member is_iomem would thus be set - memcpy would do the right thing, based on is_iomem. /Thomas > > Christian. > > > > > /Thomas > > > > > > > > > > Christian. > > > > > > > > > > > As for limited arch support for memremap cached, It looks like > > > > we only > > > > need to or in "backup" mapping modes in the memremap flags, and > > > > we'd > > > > mimic the previous behaviour. > > > > > > > > /Thomas > > > > > > > > > > > > > > /Thomas > > > > > > > > > > > > > > > > > > > >
WARNING: multiple messages have this Message-ID (diff)
From: "Thomas Hellström" <thomas.hellstrom@linux.intel.com> To: "Christian König" <christian.koenig@amd.com>, "Matthew Auld" <matthew.william.auld@gmail.com> Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>, ML dri-devel <dri-devel@lists.freedesktop.org> Subject: Re: [Intel-gfx] [PATCH v3 06/12] drm/ttm: Add a generic TTM memcpy move for page-based iomem Date: Wed, 26 May 2021 12:57:10 +0200 [thread overview] Message-ID: <fbbb896e7e886e4d41b3a319c6aa7c5bb2e8ad4e.camel@linux.intel.com> (raw) In-Reply-To: <9f8fe3af-6d49-f652-70bc-36a27007d821@amd.com> On Wed, 2021-05-26 at 12:45 +0200, Christian König wrote: > Am 26.05.21 um 09:39 schrieb Thomas Hellström: > > [SNIP] > > > > I think the long term goal is to use memremap all over the > > > > place, to > > > > just not have to bother with the __iomem annotation. But to do > > > > that io- > > > > mapping.h needs to support memremap. But for now we need to be > > > > strict > > > > about __iomem unless we're in arch specific code. That's why > > > > that > > > > dma_buf_map thing was created, but TTM memcpy was never fully > > > > adapted. > > > > > > I don't think that this will work. __iomem annotation is there > > > because we have architectures where you need to use special CPU > > > instructions for iomem access. > > > > > > That won't go away just because we use memremap(). > > > > That's true, but can we ever support those with TTM, given that we > > allow user-space mmaping that transparently may change to an iomap? > > Given that, and what's written here > > > > > > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flwn.net%2FArticles%2F653585%2F&data=04%7C01%7Cchristian.koenig%40amd.com%7C1cdcfe9d20e740308c9e08d92019785b%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637576116034492654%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=e2BFGQJcElwVxrvHcnALDWscHN7ernLekGvXHqWBcwY%3D&reserved=0 > > > > > > > > To me it sounds like if an architecture can't support memremap, we > > can't support it with TTM either. > > That was also my argument, but this is unfortunately not true. > > We already have architectures where the __iomem approach is mandatory > for kernel mappings, but work fine for userspace (don't ask me how > that > works, idk). Ugh. :/ > > That's the reason why we had to fix the UVD firmware upload in the > kernel: > > commit ba0b2275a6781b2f3919d931d63329b5548f6d5f > Author: Christian König <christian.koenig@amd.com> > Date: Tue Aug 23 11:00:17 2016 +0200 > > drm/amdgpu: use memcpy_to/fromio for UVD fw upload > > > > > In any case for this particular patch, to avoid potential > > regressions, > > OK if I just add an ioremap() in case the memremap fails? > > Well because of the issues outlined above I would actually prefer if > we > can keep the __iomem annotation around. Well, we'd do that. Since we use the dma_buf_map unconditionally. So what would happen in the above case, would be: - memremap would fail. (Otherwise I'd be terribly confused) - we retry with ioremap and the dma-buf-map member is_iomem would thus be set - memcpy would do the right thing, based on is_iomem. /Thomas > > Christian. > > > > > /Thomas > > > > > > > > > > Christian. > > > > > > > > > > > As for limited arch support for memremap cached, It looks like > > > > we only > > > > need to or in "backup" mapping modes in the memremap flags, and > > > > we'd > > > > mimic the previous behaviour. > > > > > > > > /Thomas > > > > > > > > > > > > > > /Thomas > > > > > > > > > > > > > > > > > > > > _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
next prev parent reply other threads:[~2021-05-26 10:57 UTC|newest] Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-21 15:32 [PATCH v3 00/12] drm/i915: Move LMEM (VRAM) management over to TTM Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-21 15:32 ` [PATCH v3 01/12] drm/i915: Untangle the vma pages_mutex Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-21 15:32 ` [PATCH v3 02/12] drm/i915: Don't free shared locks while shared Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-21 15:32 ` [PATCH v3 03/12] drm/i915: Fix i915_sg_page_sizes to record dma segments rather than physical pages Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-21 15:32 ` [PATCH v3 04/12] drm/i915/ttm Initialize the ttm device and memory managers Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-21 15:32 ` [PATCH v3 05/12] drm/i915/ttm: Embed a ttm buffer object in the i915 gem object Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-21 15:32 ` [PATCH v3 06/12] drm/ttm: Add a generic TTM memcpy move for page-based iomem Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-25 9:18 ` Matthew Auld 2021-05-25 9:18 ` Matthew Auld 2021-05-25 9:32 ` Thomas Hellström 2021-05-25 9:32 ` Thomas Hellström 2021-05-25 9:58 ` Matthew Auld 2021-05-25 9:58 ` Matthew Auld 2021-05-25 10:07 ` Thomas Hellström 2021-05-25 10:07 ` Thomas Hellström 2021-05-25 15:48 ` Christian König 2021-05-25 15:48 ` Christian König 2021-05-26 7:39 ` Thomas Hellström 2021-05-26 7:39 ` Thomas Hellström 2021-05-26 10:45 ` Christian König 2021-05-26 10:45 ` Christian König 2021-05-26 10:57 ` Thomas Hellström [this message] 2021-05-26 10:57 ` Thomas Hellström 2021-05-21 15:32 ` [PATCH v3 07/12] drm, drm/i915: Move the memcpy_from_wc functionality to core drm Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-24 16:45 ` Matthew Auld 2021-05-24 16:45 ` Matthew Auld 2021-05-24 18:12 ` Thomas Hellström 2021-05-24 18:12 ` Thomas Hellström 2021-05-21 15:32 ` [PATCH v3 08/12] drm/ttm: Use drm_memcpy_from_wc_dbm for TTM bo moves Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-24 18:16 ` Matthew Auld 2021-05-24 18:16 ` [Intel-gfx] " Matthew Auld 2021-05-24 18:47 ` Thomas Hellström 2021-05-24 18:47 ` [Intel-gfx] " Thomas Hellström 2021-05-26 12:48 ` Christian König 2021-05-26 12:48 ` [Intel-gfx] " Christian König 2021-05-21 15:32 ` [PATCH v3 09/12] drm/ttm: Document and optimize ttm_bo_pipeline_gutting() Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-25 11:00 ` Matthew Auld 2021-05-25 11:00 ` Matthew Auld 2021-05-25 13:37 ` Thomas Hellström 2021-05-25 13:37 ` Thomas Hellström 2021-05-21 15:32 ` [PATCH v3 10/12] drm/ttm, drm/amdgpu: Allow the driver some control over swapping Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-21 15:32 ` [PATCH v3 11/12] drm/i915/ttm: Introduce a TTM i915 gem object backend Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-21 15:32 ` [PATCH v3 12/12] drm/i915/lmem: Verify checks for lmem residency Thomas Hellström 2021-05-21 15:32 ` [Intel-gfx] " Thomas Hellström 2021-05-21 16:06 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/i915: Move LMEM (VRAM) management over to TTM (rev3) Patchwork 2021-05-21 16:09 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork 2021-05-21 16:36 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork 2021-05-24 0:10 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
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