| Message ID | 20181210011504.122604-1-drinkcat@chromium.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | iommu/io-pgtable-arm-v7s: Use DMA32 zone for page tables | expand |
Hi all, On Mon, Dec 10, 2018 at 9:15 AM Nicolas Boichat <drinkcat@chromium.org> wrote: > > This is a follow-up to the discussion in [1], [2]. > > IOMMUs using ARMv7 short-descriptor format require page tables > (level 1 and 2) to be allocated within the first 4GB of RAM, even > on 64-bit systems. > > For L1 tables that are bigger than a page, we can just use __get_free_pages > with GFP_DMA32 (on arm64 systems only, arm would still use GFP_DMA). > > For L2 tables that only take 1KB, it would be a waste to allocate a full > page, so we considered 3 approaches: > 1. This series, adding support for GFP_DMA32 slab caches. > 2. genalloc, which requires pre-allocating the maximum number of L2 page > tables (4096, so 4MB of memory). > 3. page_frag, which is not very memory-efficient as it is unable to reuse > freed fragments until the whole page is freed. [3] > > This series is the most memory-efficient approach. Does anyone have any further comment on this series? If not, which maintainer is going to pick this up? I assume Andrew Morton? Thanks, > stable@ note: > We confirmed that this is a regression, and IOMMU errors happen on 4.19 > and linux-next/master on MT8173 (elm, Acer Chromebook R13). The issue > most likely starts from commit ad67f5a6545f ("arm64: replace ZONE_DMA > with ZONE_DMA32"), i.e. 4.15, and presumably breaks a number of Mediatek > platforms (and maybe others?). > > [1] https://lists.linuxfoundation.org/pipermail/iommu/2018-November/030876.html > [2] https://lists.linuxfoundation.org/pipermail/iommu/2018-December/031696.html > [3] https://patchwork.codeaurora.org/patch/671639/ > > Changes since v1: > - Add support for SLAB_CACHE_DMA32 in slab and slub (patches 1/2) > - iommu/io-pgtable-arm-v7s (patch 3): > - Changed approach to use SLAB_CACHE_DMA32 added by the previous > commit. > - Use DMA or DMA32 depending on the architecture (DMA for arm, > DMA32 for arm64). > > Changes since v2: > - Reworded and expanded commit messages > - Added cache_dma32 documentation in PATCH 2/3. > > v3 used the page_frag approach, see [3]. > > Changes since v4: > - Dropped change that removed GFP_DMA32 from GFP_SLAB_BUG_MASK: > instead we can just call kmem_cache_*alloc without GFP_DMA32 > parameter. This also means that we can drop PATCH v4 1/3, as we > do not make any changes in GFP flag verification. > - Dropped hunks that added cache_dma32 sysfs file, and moved > the hunks to PATCH v5 3/3, so that maintainer can decide whether > to pick the change independently. > > Changes since v5: > - Rename ARM_V7S_TABLE_SLAB_CACHE to ARM_V7S_TABLE_SLAB_FLAGS. > - Add stable@ to cc. > > Nicolas Boichat (3): > mm: Add support for kmem caches in DMA32 zone > iommu/io-pgtable-arm-v7s: Request DMA32 memory, and improve debugging > mm: Add /sys/kernel/slab/cache/cache_dma32 > > Documentation/ABI/testing/sysfs-kernel-slab | 9 +++++++++ > drivers/iommu/io-pgtable-arm-v7s.c | 19 +++++++++++++++---- > include/linux/slab.h | 2 ++ > mm/slab.c | 2 ++ > mm/slab.h | 3 ++- > mm/slab_common.c | 2 +- > mm/slub.c | 16 ++++++++++++++++ > tools/vm/slabinfo.c | 7 ++++++- > 8 files changed, 53 insertions(+), 7 deletions(-) > > -- > 2.20.0.rc2.403.gdbc3b29805-goog >
On Wed, Jan 02, 2019 at 01:51:45PM +0800, Nicolas Boichat wrote: > Does anyone have any further comment on this series? If not, which > maintainer is going to pick this up? I assume Andrew Morton? Probably, yes. I don't like to carry the mm-changes in iommu-tree, so this should go through mm. Regards, Joerg
Hi Andrew, On Fri, Jan 11, 2019 at 6:21 PM Joerg Roedel <joro@8bytes.org> wrote: > > On Wed, Jan 02, 2019 at 01:51:45PM +0800, Nicolas Boichat wrote: > > Does anyone have any further comment on this series? If not, which > > maintainer is going to pick this up? I assume Andrew Morton? > > Probably, yes. I don't like to carry the mm-changes in iommu-tree, so > this should go through mm. Gentle ping on this series, it seems like it's better if it goes through your tree. Series still applies cleanly on linux-next, but I'm happy to resend if that helps. Thanks! > Regards, > > Joerg
On 1/22/19 11:51 PM, Nicolas Boichat wrote: > Hi Andrew, > > On Fri, Jan 11, 2019 at 6:21 PM Joerg Roedel <joro@8bytes.org> wrote: >> >> On Wed, Jan 02, 2019 at 01:51:45PM +0800, Nicolas Boichat wrote: >> > Does anyone have any further comment on this series? If not, which >> > maintainer is going to pick this up? I assume Andrew Morton? >> >> Probably, yes. I don't like to carry the mm-changes in iommu-tree, so >> this should go through mm. > > Gentle ping on this series, it seems like it's better if it goes > through your tree. > > Series still applies cleanly on linux-next, but I'm happy to resend if > that helps. Ping, Andrew? > Thanks! > >> Regards, >> >> Joerg >
On Thu, Feb 14, 2019 at 1:12 AM Vlastimil Babka <vbabka@suse.cz> wrote: > > On 1/22/19 11:51 PM, Nicolas Boichat wrote: > > Hi Andrew, > > > > On Fri, Jan 11, 2019 at 6:21 PM Joerg Roedel <joro@8bytes.org> wrote: > >> > >> On Wed, Jan 02, 2019 at 01:51:45PM +0800, Nicolas Boichat wrote: > >> > Does anyone have any further comment on this series? If not, which > >> > maintainer is going to pick this up? I assume Andrew Morton? > >> > >> Probably, yes. I don't like to carry the mm-changes in iommu-tree, so > >> this should go through mm. > > > > Gentle ping on this series, it seems like it's better if it goes > > through your tree. > > > > Series still applies cleanly on linux-next, but I'm happy to resend if > > that helps. > > Ping, Andrew? Another gentle ping, I still don't see these patches in mmot[ms]. Thanks. > > Thanks! > > > >> Regards, > >> > >> Joerg > > >
On Mon, Feb 25, 2019 at 8:23 AM Nicolas Boichat <drinkcat@chromium.org> wrote: > > On Thu, Feb 14, 2019 at 1:12 AM Vlastimil Babka <vbabka@suse.cz> wrote: > > > > On 1/22/19 11:51 PM, Nicolas Boichat wrote: > > > Hi Andrew, > > > > > > On Fri, Jan 11, 2019 at 6:21 PM Joerg Roedel <joro@8bytes.org> wrote: > > >> > > >> On Wed, Jan 02, 2019 at 01:51:45PM +0800, Nicolas Boichat wrote: > > >> > Does anyone have any further comment on this series? If not, which > > >> > maintainer is going to pick this up? I assume Andrew Morton? > > >> > > >> Probably, yes. I don't like to carry the mm-changes in iommu-tree, so > > >> this should go through mm. > > > > > > Gentle ping on this series, it seems like it's better if it goes > > > through your tree. > > > > > > Series still applies cleanly on linux-next, but I'm happy to resend if > > > that helps. > > > > Ping, Andrew? > > Another gentle ping, I still don't see these patches in mmot[ms]. Thanks. Andrew: AFAICT this still applies cleanly on linux-next/master, so I don't plan to resend... is there any other issues with this series? This is a regression, so it'd be nice to have it fixed in mainline, eventually. Thanks, > > > Thanks! > > > > > >> Regards, > > >> > > >> Joerg > > > > >
On Tue, 19 Mar 2019 15:41:43 +0800 Nicolas Boichat <drinkcat@chromium.org> wrote: > On Mon, Feb 25, 2019 at 8:23 AM Nicolas Boichat <drinkcat@chromium.org> wrote: > > > > On Thu, Feb 14, 2019 at 1:12 AM Vlastimil Babka <vbabka@suse.cz> wrote: > > > > > > On 1/22/19 11:51 PM, Nicolas Boichat wrote: > > > > Hi Andrew, > > > > > > > > On Fri, Jan 11, 2019 at 6:21 PM Joerg Roedel <joro@8bytes.org> wrote: > > > >> > > > >> On Wed, Jan 02, 2019 at 01:51:45PM +0800, Nicolas Boichat wrote: > > > >> > Does anyone have any further comment on this series? If not, which > > > >> > maintainer is going to pick this up? I assume Andrew Morton? > > > >> > > > >> Probably, yes. I don't like to carry the mm-changes in iommu-tree, so > > > >> this should go through mm. > > > > > > > > Gentle ping on this series, it seems like it's better if it goes > > > > through your tree. > > > > > > > > Series still applies cleanly on linux-next, but I'm happy to resend if > > > > that helps. > > > > > > Ping, Andrew? > > > > Another gentle ping, I still don't see these patches in mmot[ms]. Thanks. > > Andrew: AFAICT this still applies cleanly on linux-next/master, so I > don't plan to resend... is there any other issues with this series? > > This is a regression, so it'd be nice to have it fixed in mainline, eventually. Sorry, seeing "iommu" and "arm" made these escape my gimlet eye. I'm only seeing acks on [1/3]. What's the review status of [2/3] and [3/3]?
On Wed, Mar 20, 2019 at 1:56 AM Andrew Morton <akpm@linux-foundation.org> wrote: > > On Tue, 19 Mar 2019 15:41:43 +0800 Nicolas Boichat <drinkcat@chromium.org> wrote: > > > On Mon, Feb 25, 2019 at 8:23 AM Nicolas Boichat <drinkcat@chromium.org> wrote: > > > > > > On Thu, Feb 14, 2019 at 1:12 AM Vlastimil Babka <vbabka@suse.cz> wrote: > > > > > > > > On 1/22/19 11:51 PM, Nicolas Boichat wrote: > > > > > Hi Andrew, > > > > > > > > > > On Fri, Jan 11, 2019 at 6:21 PM Joerg Roedel <joro@8bytes.org> wrote: > > > > >> > > > > >> On Wed, Jan 02, 2019 at 01:51:45PM +0800, Nicolas Boichat wrote: > > > > >> > Does anyone have any further comment on this series? If not, which > > > > >> > maintainer is going to pick this up? I assume Andrew Morton? > > > > >> > > > > >> Probably, yes. I don't like to carry the mm-changes in iommu-tree, so > > > > >> this should go through mm. > > > > > > > > > > Gentle ping on this series, it seems like it's better if it goes > > > > > through your tree. > > > > > > > > > > Series still applies cleanly on linux-next, but I'm happy to resend if > > > > > that helps. > > > > > > > > Ping, Andrew? > > > > > > Another gentle ping, I still don't see these patches in mmot[ms]. Thanks. > > > > Andrew: AFAICT this still applies cleanly on linux-next/master, so I > > don't plan to resend... is there any other issues with this series? > > > > This is a regression, so it'd be nice to have it fixed in mainline, eventually. > > Sorry, seeing "iommu" and "arm" made these escape my gimlet eye. Thanks for picking them up! > I'm only seeing acks on [1/3]. What's the review status of [2/3] and [3/3]? Replied on the notification, [2/3] had a Ack, [3/3] is somewhat controversial.
This is a follow-up to the discussion in [1], [2]. IOMMUs using ARMv7 short-descriptor format require page tables (level 1 and 2) to be allocated within the first 4GB of RAM, even on 64-bit systems. For L1 tables that are bigger than a page, we can just use __get_free_pages with GFP_DMA32 (on arm64 systems only, arm would still use GFP_DMA). For L2 tables that only take 1KB, it would be a waste to allocate a full page, so we considered 3 approaches: 1. This series, adding support for GFP_DMA32 slab caches. 2. genalloc, which requires pre-allocating the maximum number of L2 page tables (4096, so 4MB of memory). 3. page_frag, which is not very memory-efficient as it is unable to reuse freed fragments until the whole page is freed. [3] This series is the most memory-efficient approach. stable@ note: We confirmed that this is a regression, and IOMMU errors happen on 4.19 and linux-next/master on MT8173 (elm, Acer Chromebook R13). The issue most likely starts from commit ad67f5a6545f ("arm64: replace ZONE_DMA with ZONE_DMA32"), i.e. 4.15, and presumably breaks a number of Mediatek platforms (and maybe others?). [1] https://lists.linuxfoundation.org/pipermail/iommu/2018-November/030876.html [2] https://lists.linuxfoundation.org/pipermail/iommu/2018-December/031696.html [3] https://patchwork.codeaurora.org/patch/671639/ Changes since v1: - Add support for SLAB_CACHE_DMA32 in slab and slub (patches 1/2) - iommu/io-pgtable-arm-v7s (patch 3): - Changed approach to use SLAB_CACHE_DMA32 added by the previous commit. - Use DMA or DMA32 depending on the architecture (DMA for arm, DMA32 for arm64). Changes since v2: - Reworded and expanded commit messages - Added cache_dma32 documentation in PATCH 2/3. v3 used the page_frag approach, see [3]. Changes since v4: - Dropped change that removed GFP_DMA32 from GFP_SLAB_BUG_MASK: instead we can just call kmem_cache_*alloc without GFP_DMA32 parameter. This also means that we can drop PATCH v4 1/3, as we do not make any changes in GFP flag verification. - Dropped hunks that added cache_dma32 sysfs file, and moved the hunks to PATCH v5 3/3, so that maintainer can decide whether to pick the change independently. Changes since v5: - Rename ARM_V7S_TABLE_SLAB_CACHE to ARM_V7S_TABLE_SLAB_FLAGS. - Add stable@ to cc. Nicolas Boichat (3): mm: Add support for kmem caches in DMA32 zone iommu/io-pgtable-arm-v7s: Request DMA32 memory, and improve debugging mm: Add /sys/kernel/slab/cache/cache_dma32 Documentation/ABI/testing/sysfs-kernel-slab | 9 +++++++++ drivers/iommu/io-pgtable-arm-v7s.c | 19 +++++++++++++++---- include/linux/slab.h | 2 ++ mm/slab.c | 2 ++ mm/slab.h | 3 ++- mm/slab_common.c | 2 +- mm/slub.c | 16 ++++++++++++++++ tools/vm/slabinfo.c | 7 ++++++- 8 files changed, 53 insertions(+), 7 deletions(-)