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Christoph Hellwig

2022-Feb-07 06:32 UTC

[Nouveau] start sorting out the ZONE_DEVICE refcount mess

Hi all,

this series removes the offset by one refcount for ZONE_DEVICE pages
that are freed back to the driver owning them, which is just device
private ones for now, but also the planned device coherent pages
and the ehanced p2p ones pending.

It does not address the fsdax pages yet, which will be attacked in a
follow on series.

Diffstat:
 arch/arm64/mm/mmu.c                      |    1 
 arch/powerpc/kvm/book3s_hv_uvmem.c       |    1 
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c |    2 
 drivers/gpu/drm/amd/amdkfd/kfd_priv.h    |    1 
 drivers/gpu/drm/drm_cache.c              |    2 
 drivers/gpu/drm/nouveau/nouveau_dmem.c   |    3 -
 drivers/gpu/drm/nouveau/nouveau_svm.c    |    1 
 drivers/infiniband/core/rw.c             |    1 
 drivers/nvdimm/pmem.h                    |    1 
 drivers/nvme/host/pci.c                  |    1 
 drivers/nvme/target/io-cmd-bdev.c        |    1 
 fs/Kconfig                               |    2 
 fs/fuse/virtio_fs.c                      |    1 
 include/linux/hmm.h                      |    9 ----
 include/linux/memremap.h                 |   22 +++++++++-
 include/linux/mm.h                       |   59 ++++-------------------------
 lib/test_hmm.c                           |    4 +
 mm/Kconfig                               |    4 -
 mm/internal.h                            |    2 
 mm/memcontrol.c                          |   11 +----
 mm/memremap.c                            |   63 ++++++++++++++++---------------
 mm/migrate.c                             |    6 --
 mm/swap.c                                |   49 ++----------------------
 23 files changed, 90 insertions(+), 157 deletions(-)

Christoph Hellwig

2022-Feb-07 06:32 UTC

head link

[Nouveau] [PATCH 1/8] mm: remove a pointless CONFIG_ZONE_DEVICE check in memremap_pages

memremap.c is only built when CONFIG_ZONE_DEVICE is set, so remove
the superflous extra check.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 mm/memremap.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/memremap.c b/mm/memremap.c
index 6aa5f0c2d11fda..5f04a0709e436e 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -328,8 +328,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
 		}
 		break;
 	case MEMORY_DEVICE_FS_DAX:
-		if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||
-		    IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
+		if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
 			WARN(1, "File system DAX not supported\n");
 			return ERR_PTR(-EINVAL);
 		}
-- 
2.30.2

Christoph Hellwig

2022-Feb-07 06:32 UTC

head link

[Nouveau] [PATCH 2/8] mm: remove the KERNEL guard from <linux/mm.h>

__KERNEL__ ifdefs don't make sense outside of include/uapi/.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 include/linux/mm.h | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 213cc569b19223..7b46174989b086 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3,9 +3,6 @@
 #define _LINUX_MM_H
 
 #include <linux/errno.h>
-
-#ifdef __KERNEL__
-
 #include <linux/mmdebug.h>
 #include <linux/gfp.h>
 #include <linux/bug.h>
@@ -3381,5 +3378,4 @@ madvise_set_anon_name(struct mm_struct *mm, unsigned long
start,
 }
 #endif
 
-#endif /* __KERNEL__ */
 #endif /* _LINUX_MM_H */
-- 
2.30.2

Christoph Hellwig

2022-Feb-07 06:32 UTC

head link

[Nouveau] [PATCH 3/8] mm: remove pointless includes from <linux/hmm.h>

hmm.h pulls in the world for no good reason at all.  Remove the
includes and push a few ones into the users instead.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 1 +
 drivers/gpu/drm/nouveau/nouveau_dmem.c   | 1 +
 include/linux/hmm.h                      | 9 ++-------
 lib/test_hmm.c                           | 2 ++
 4 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index ed5385137f4831..cb835f95a76e66 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -24,6 +24,7 @@
 #include <linux/hmm.h>
 #include <linux/dma-direction.h>
 #include <linux/dma-mapping.h>
+#include <linux/migrate.h>
 #include "amdgpu_sync.h"
 #include "amdgpu_object.h"
 #include "amdgpu_vm.h"
diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c
b/drivers/gpu/drm/nouveau/nouveau_dmem.c
index 3828aafd3ac46f..e886a3b9e08c7d 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c
@@ -39,6 +39,7 @@
 
 #include <linux/sched/mm.h>
 #include <linux/hmm.h>
+#include <linux/migrate.h>
 
 /*
  * FIXME: this is ugly right now we are using TTM to allocate vram and we pin
diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index 2fd2e91d5107c0..d5a6f101f843e6 100644
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -9,14 +9,9 @@
 #ifndef LINUX_HMM_H
 #define LINUX_HMM_H
 
-#include <linux/kconfig.h>
-#include <linux/pgtable.h>
+#include <linux/mm.h>
 
-#include <linux/device.h>
-#include <linux/migrate.h>
-#include <linux/memremap.h>
-#include <linux/completion.h>
-#include <linux/mmu_notifier.h>
+struct mmu_interval_notifier;
 
 /*
  * On output:
diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 767538089a62e4..396beee6b061d4 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -26,6 +26,8 @@
 #include <linux/sched/mm.h>
 #include <linux/platform_device.h>
 #include <linux/rmap.h>
+#include <linux/mmu_notifier.h>
+#include <linux/migrate.h>
 
 #include "test_hmm_uapi.h"
 
-- 
2.30.2

Christoph Hellwig

2022-Feb-07 06:32 UTC

head link

[Nouveau] [PATCH 4/8] mm: move free_devmap_managed_page to memremap.c

free_devmap_managed_page has nothing to do with the code in swap.c,
move it to live with the rest of the code for devmap handling.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 include/linux/mm.h |  1 -
 mm/memremap.c      | 21 +++++++++++++++++++++
 mm/swap.c          | 23 -----------------------
 3 files changed, 21 insertions(+), 24 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7b46174989b086..91dd0bc786a9ec 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1092,7 +1092,6 @@ static inline bool is_zone_movable_page(const struct page
*page)
 }
 
 #ifdef CONFIG_DEV_PAGEMAP_OPS
-void free_devmap_managed_page(struct page *page);
 DECLARE_STATIC_KEY_FALSE(devmap_managed_key);
 
 static inline bool page_is_devmap_managed(struct page *page)
diff --git a/mm/memremap.c b/mm/memremap.c
index 5f04a0709e436e..55d23e9f5c04ec 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -501,4 +501,25 @@ void free_devmap_managed_page(struct page *page)
 	page->mapping = NULL;
 	page->pgmap->ops->page_free(page);
 }
+
+void put_devmap_managed_page(struct page *page)
+{
+	int count;
+
+	if (WARN_ON_ONCE(!page_is_devmap_managed(page)))
+		return;
+
+	count = page_ref_dec_return(page);
+
+	/*
+	 * devmap page refcounts are 1-based, rather than 0-based: if
+	 * refcount is 1, then the page is free and the refcount is
+	 * stable because nobody holds a reference on the page.
+	 */
+	if (count == 1)
+		free_devmap_managed_page(page);
+	else if (!count)
+		__put_page(page);
+}
+EXPORT_SYMBOL(put_devmap_managed_page);
 #endif /* CONFIG_DEV_PAGEMAP_OPS */
diff --git a/mm/swap.c b/mm/swap.c
index bcf3ac288b56d5..08058f74cae23e 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -1153,26 +1153,3 @@ void __init swap_setup(void)
 	 * _really_ don't want to cluster much more
 	 */
 }
-
-#ifdef CONFIG_DEV_PAGEMAP_OPS
-void put_devmap_managed_page(struct page *page)
-{
-	int count;
-
-	if (WARN_ON_ONCE(!page_is_devmap_managed(page)))
-		return;
-
-	count = page_ref_dec_return(page);
-
-	/*
-	 * devmap page refcounts are 1-based, rather than 0-based: if
-	 * refcount is 1, then the page is free and the refcount is
-	 * stable because nobody holds a reference on the page.
-	 */
-	if (count == 1)
-		free_devmap_managed_page(page);
-	else if (!count)
-		__put_page(page);
-}
-EXPORT_SYMBOL(put_devmap_managed_page);
-#endif
-- 
2.30.2

Christoph Hellwig

2022-Feb-07 06:32 UTC

head link

[Nouveau] [PATCH 5/8] mm: simplify freeing of devmap managed pages

Make put_devmap_managed_page return if it took charge of the page
or not and remove the separate page_is_devmap_managed helper.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 include/linux/mm.h | 34 ++++++++++------------------------
 mm/memremap.c      | 20 +++++++++-----------
 mm/swap.c          | 10 +---------
 3 files changed, 20 insertions(+), 44 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 91dd0bc786a9ec..26baadcef4556b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1094,33 +1094,24 @@ static inline bool is_zone_movable_page(const struct
page *page)
 #ifdef CONFIG_DEV_PAGEMAP_OPS
 DECLARE_STATIC_KEY_FALSE(devmap_managed_key);
 
-static inline bool page_is_devmap_managed(struct page *page)
+bool __put_devmap_managed_page(struct page *page);
+static inline bool put_devmap_managed_page(struct page *page)
 {
 	if (!static_branch_unlikely(&devmap_managed_key))
 		return false;
 	if (!is_zone_device_page(page))
 		return false;
-	switch (page->pgmap->type) {
-	case MEMORY_DEVICE_PRIVATE:
-	case MEMORY_DEVICE_FS_DAX:
-		return true;
-	default:
-		break;
-	}
-	return false;
+	if (page->pgmap->type != MEMORY_DEVICE_PRIVATE &&
+	    page->pgmap->type != MEMORY_DEVICE_FS_DAX)
+		return false;
+	return __put_devmap_managed_page(page);
 }
 
-void put_devmap_managed_page(struct page *page);
-
 #else /* CONFIG_DEV_PAGEMAP_OPS */
-static inline bool page_is_devmap_managed(struct page *page)
+static inline bool put_devmap_managed_page(struct page *page)
 {
 	return false;
 }
-
-static inline void put_devmap_managed_page(struct page *page)
-{
-}
 #endif /* CONFIG_DEV_PAGEMAP_OPS */
 
 static inline bool is_device_private_page(const struct page *page)
@@ -1220,16 +1211,11 @@ static inline void put_page(struct page *page)
 	struct folio *folio = page_folio(page);
 
 	/*
-	 * For devmap managed pages we need to catch refcount transition from
-	 * 2 to 1, when refcount reach one it means the page is free and we
-	 * need to inform the device driver through callback. See
-	 * include/linux/memremap.h and HMM for details.
+	 * For some devmap managed pages we need to catch refcount transition
+	 * from 2 to 1:
 	 */
-	if (page_is_devmap_managed(&folio->page)) {
-		put_devmap_managed_page(&folio->page);
+	if (put_devmap_managed_page(&folio->page))
 		return;
-	}
-
 	folio_put(folio);
 }
 
diff --git a/mm/memremap.c b/mm/memremap.c
index 55d23e9f5c04ec..f41233a67edb12 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -502,24 +502,22 @@ void free_devmap_managed_page(struct page *page)
 	page->pgmap->ops->page_free(page);
 }
 
-void put_devmap_managed_page(struct page *page)
+bool __put_devmap_managed_page(struct page *page)
 {
-	int count;
-
-	if (WARN_ON_ONCE(!page_is_devmap_managed(page)))
-		return;
-
-	count = page_ref_dec_return(page);
-
 	/*
 	 * devmap page refcounts are 1-based, rather than 0-based: if
 	 * refcount is 1, then the page is free and the refcount is
 	 * stable because nobody holds a reference on the page.
 	 */
-	if (count == 1)
+	switch (page_ref_dec_return(page)) {
+	case 1:
 		free_devmap_managed_page(page);
-	else if (!count)
+		break;
+	case 0:
 		__put_page(page);
+		break;
+	}
+	return true;
 }
-EXPORT_SYMBOL(put_devmap_managed_page);
+EXPORT_SYMBOL(__put_devmap_managed_page);
 #endif /* CONFIG_DEV_PAGEMAP_OPS */
diff --git a/mm/swap.c b/mm/swap.c
index 08058f74cae23e..25b55c56614311 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -930,16 +930,8 @@ void release_pages(struct page **pages, int nr)
 				unlock_page_lruvec_irqrestore(lruvec, flags);
 				lruvec = NULL;
 			}
-			/*
-			 * ZONE_DEVICE pages that return 'false' from
-			 * page_is_devmap_managed() do not require special
-			 * processing, and instead, expect a call to
-			 * put_page_testzero().
-			 */
-			if (page_is_devmap_managed(page)) {
-				put_devmap_managed_page(page);
+			if (put_devmap_managed_page(page))
 				continue;
-			}
 			if (put_page_testzero(page))
 				put_dev_pagemap(page->pgmap);
 			continue;
-- 
2.30.2

Christoph Hellwig

2022-Feb-07 06:32 UTC

head link

[Nouveau] [PATCH 6/8] mm: don't include <linux/memremap.h> in <linux/mm.h>

Move the check for the actual pgmap types that need the free at refcount
one behavior into the out of line helper, and thus avoid the need to
pull memremap.h into mm.h.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 arch/arm64/mm/mmu.c                    |  1 +
 drivers/gpu/drm/amd/amdkfd/kfd_priv.h  |  1 +
 drivers/gpu/drm/drm_cache.c            |  2 +-
 drivers/gpu/drm/nouveau/nouveau_dmem.c |  1 +
 drivers/gpu/drm/nouveau/nouveau_svm.c  |  1 +
 drivers/infiniband/core/rw.c           |  1 +
 drivers/nvdimm/pmem.h                  |  1 +
 drivers/nvme/host/pci.c                |  1 +
 drivers/nvme/target/io-cmd-bdev.c      |  1 +
 fs/fuse/virtio_fs.c                    |  1 +
 include/linux/memremap.h               | 18 ++++++++++++++++++
 include/linux/mm.h                     | 20 --------------------
 lib/test_hmm.c                         |  1 +
 mm/memremap.c                          |  6 +++++-
 14 files changed, 34 insertions(+), 22 deletions(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index acfae9b41cc8c9..580abae6c0b93f 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -17,6 +17,7 @@
 #include <linux/mman.h>
 #include <linux/nodemask.h>
 #include <linux/memblock.h>
+#include <linux/memremap.h>
 #include <linux/memory.h>
 #include <linux/fs.h>
 #include <linux/io.h>
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index ea68f3b3a4e9cb..6d643b4b791d87 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -25,6 +25,7 @@
 
 #include <linux/hashtable.h>
 #include <linux/mmu_notifier.h>
+#include <linux/memremap.h>
 #include <linux/mutex.h>
 #include <linux/types.h>
 #include <linux/atomic.h>
diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index f19d9acbe95936..50b8a088f763a6 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -27,11 +27,11 @@
 /*
  * Authors: Thomas Hellstr?m <thomas-at-tungstengraphics-dot-com>
  */
-
 #include <linux/dma-buf-map.h>
 #include <linux/export.h>
 #include <linux/highmem.h>
 #include <linux/cc_platform.h>
+#include <linux/ioport.h>
 #include <xen/xen.h>
 
 #include <drm/drm_cache.h>
diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c
b/drivers/gpu/drm/nouveau/nouveau_dmem.c
index e886a3b9e08c7d..a5cdfbe32b5e54 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c
@@ -39,6 +39,7 @@
 
 #include <linux/sched/mm.h>
 #include <linux/hmm.h>
+#include <linux/memremap.h>
 #include <linux/migrate.h>
 
 /*
diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c
b/drivers/gpu/drm/nouveau/nouveau_svm.c
index 266809e511e2c1..090b9b47708cca 100644
--- a/drivers/gpu/drm/nouveau/nouveau_svm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
@@ -35,6 +35,7 @@
 #include <linux/sched/mm.h>
 #include <linux/sort.h>
 #include <linux/hmm.h>
+#include <linux/memremap.h>
 #include <linux/rmap.h>
 
 struct nouveau_svm {
diff --git a/drivers/infiniband/core/rw.c b/drivers/infiniband/core/rw.c
index 5a3bd41b331c93..4d98f931a13ddd 100644
--- a/drivers/infiniband/core/rw.c
+++ b/drivers/infiniband/core/rw.c
@@ -2,6 +2,7 @@
 /*
  * Copyright (c) 2016 HGST, a Western Digital Company.
  */
+#include <linux/memremap.h>
 #include <linux/moduleparam.h>
 #include <linux/slab.h>
 #include <linux/pci-p2pdma.h>
diff --git a/drivers/nvdimm/pmem.h b/drivers/nvdimm/pmem.h
index 59cfe13ea8a85c..1f51a23614299b 100644
--- a/drivers/nvdimm/pmem.h
+++ b/drivers/nvdimm/pmem.h
@@ -3,6 +3,7 @@
 #define __NVDIMM_PMEM_H__
 #include <linux/page-flags.h>
 #include <linux/badblocks.h>
+#include <linux/memremap.h>
 #include <linux/types.h>
 #include <linux/pfn_t.h>
 #include <linux/fs.h>
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 6a99ed68091589..ab15bc72710dbe 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -15,6 +15,7 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/memremap.h>
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
diff --git a/drivers/nvme/target/io-cmd-bdev.c
b/drivers/nvme/target/io-cmd-bdev.c
index 70ca9dfc1771a9..a141446db1bea3 100644
--- a/drivers/nvme/target/io-cmd-bdev.c
+++ b/drivers/nvme/target/io-cmd-bdev.c
@@ -6,6 +6,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/blkdev.h>
 #include <linux/blk-integrity.h>
+#include <linux/memremap.h>
 #include <linux/module.h>
 #include "nvmet.h"
 
diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index 9d737904d07c0b..86b7dbb6a0d43e 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -8,6 +8,7 @@
 #include <linux/dax.h>
 #include <linux/pci.h>
 #include <linux/pfn_t.h>
+#include <linux/memremap.h>
 #include <linux/module.h>
 #include <linux/virtio.h>
 #include <linux/virtio_fs.h>
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 1fafcc38acbad6..514ab46f597e5c 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -1,6 +1,8 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_MEMREMAP_H_
 #define _LINUX_MEMREMAP_H_
+
+#include <linux/mm.h>
 #include <linux/range.h>
 #include <linux/ioport.h>
 #include <linux/percpu-refcount.h>
@@ -129,6 +131,22 @@ static inline unsigned long pgmap_vmemmap_nr(struct
dev_pagemap *pgmap)
 	return 1 << pgmap->vmemmap_shift;
 }
 
+static inline bool is_device_private_page(const struct page *page)
+{
+	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
+		IS_ENABLED(CONFIG_DEVICE_PRIVATE) &&
+		is_zone_device_page(page) &&
+		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
+}
+
+static inline bool is_pci_p2pdma_page(const struct page *page)
+{
+	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
+		IS_ENABLED(CONFIG_PCI_P2PDMA) &&
+		is_zone_device_page(page) &&
+		page->pgmap->type == MEMORY_DEVICE_PCI_P2PDMA;
+}
+
 #ifdef CONFIG_ZONE_DEVICE
 void *memremap_pages(struct dev_pagemap *pgmap, int nid);
 void memunmap_pages(struct dev_pagemap *pgmap);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 26baadcef4556b..80fccfe31c3444 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -23,7 +23,6 @@
 #include <linux/err.h>
 #include <linux/page-flags.h>
 #include <linux/page_ref.h>
-#include <linux/memremap.h>
 #include <linux/overflow.h>
 #include <linux/sizes.h>
 #include <linux/sched.h>
@@ -1101,9 +1100,6 @@ static inline bool put_devmap_managed_page(struct page
*page)
 		return false;
 	if (!is_zone_device_page(page))
 		return false;
-	if (page->pgmap->type != MEMORY_DEVICE_PRIVATE &&
-	    page->pgmap->type != MEMORY_DEVICE_FS_DAX)
-		return false;
 	return __put_devmap_managed_page(page);
 }
 
@@ -1114,22 +1110,6 @@ static inline bool put_devmap_managed_page(struct page
*page)
 }
 #endif /* CONFIG_DEV_PAGEMAP_OPS */
 
-static inline bool is_device_private_page(const struct page *page)
-{
-	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
-		IS_ENABLED(CONFIG_DEVICE_PRIVATE) &&
-		is_zone_device_page(page) &&
-		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
-}
-
-static inline bool is_pci_p2pdma_page(const struct page *page)
-{
-	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
-		IS_ENABLED(CONFIG_PCI_P2PDMA) &&
-		is_zone_device_page(page) &&
-		page->pgmap->type == MEMORY_DEVICE_PCI_P2PDMA;
-}
-
 /* 127: arbitrary random number, small enough to assemble well */
 #define folio_ref_zero_or_close_to_overflow(folio) \
 	((unsigned int) folio_ref_count(folio) + 127u <= 127u)
diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 396beee6b061d4..e5fc14ba71f33e 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -12,6 +12,7 @@
 #include <linux/kernel.h>
 #include <linux/cdev.h>
 #include <linux/device.h>
+#include <linux/memremap.h>
 #include <linux/mutex.h>
 #include <linux/rwsem.h>
 #include <linux/sched.h>
diff --git a/mm/memremap.c b/mm/memremap.c
index f41233a67edb12..a0ece2344c2cab 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -4,7 +4,7 @@
 #include <linux/io.h>
 #include <linux/kasan.h>
 #include <linux/memory_hotplug.h>
-#include <linux/mm.h>
+#include <linux/memremap.h>
 #include <linux/pfn_t.h>
 #include <linux/swap.h>
 #include <linux/mmzone.h>
@@ -504,6 +504,10 @@ void free_devmap_managed_page(struct page *page)
 
 bool __put_devmap_managed_page(struct page *page)
 {
+	if (page->pgmap->type != MEMORY_DEVICE_PRIVATE &&
+	    page->pgmap->type != MEMORY_DEVICE_FS_DAX)
+		return false;
+
 	/*
 	 * devmap page refcounts are 1-based, rather than 0-based: if
 	 * refcount is 1, then the page is free and the refcount is
-- 
2.30.2

Christoph Hellwig

2022-Feb-07 06:32 UTC

head link

[Nouveau] [PATCH 7/8] mm: remove the extra ZONE_DEVICE struct page refcount

ZONE_DEVICE struct pages have an extra reference count that complicates
the code for put_page() and several places in the kernel that need to
check the reference count to see that a page is not being used (gup,
compaction, migration, etc.). Clean up the code so the reference count
doesn't need to be treated specially for ZONE_DEVICE pages.

Note that this excludes the special idle page wakeup for fsdax pages,
which still happens at refcount 1.  This is a separate issue and will
be sorted out later.  Given that only fsdax pages require the
notifiacation when the refcount hits 1 now, the PAGEMAP_OPS Kconfig
symbol can go away and be replaced with a FS_DAX check for this hook
in the put_page fastpath.

Based on an earlier patch from Ralph Campbell <rcampbell at nvidia.com>.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 arch/powerpc/kvm/book3s_hv_uvmem.c       |  1 -
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c |  1 -
 drivers/gpu/drm/nouveau/nouveau_dmem.c   |  1 -
 fs/Kconfig                               |  1 -
 include/linux/memremap.h                 | 12 +++--
 include/linux/mm.h                       |  6 +--
 lib/test_hmm.c                           |  1 -
 mm/Kconfig                               |  4 --
 mm/internal.h                            |  2 +
 mm/memcontrol.c                          | 11 ++---
 mm/memremap.c                            | 57 ++++++++----------------
 mm/migrate.c                             |  6 ---
 mm/swap.c                                | 16 ++-----
 13 files changed, 36 insertions(+), 83 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c
b/arch/powerpc/kvm/book3s_hv_uvmem.c
index e414ca44839fd1..8b6438fa18fc2b 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -712,7 +712,6 @@ static struct page *kvmppc_uvmem_get_page(unsigned long gpa,
struct kvm *kvm)
 
 	dpage = pfn_to_page(uvmem_pfn);
 	dpage->zone_device_data = pvt;
-	get_page(dpage);
 	lock_page(dpage);
 	return dpage;
 out_clear:
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index cb835f95a76e66..e27ca375876230 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -225,7 +225,6 @@ svm_migrate_get_vram_page(struct svm_range *prange, unsigned
long pfn)
 	page = pfn_to_page(pfn);
 	svm_range_bo_ref(prange->svm_bo);
 	page->zone_device_data = prange->svm_bo;
-	get_page(page);
 	lock_page(page);
 }
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c
b/drivers/gpu/drm/nouveau/nouveau_dmem.c
index a5cdfbe32b5e54..7ba66ad68a8a1e 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c
@@ -326,7 +326,6 @@ nouveau_dmem_page_alloc_locked(struct nouveau_drm *drm)
 			return NULL;
 	}
 
-	get_page(page);
 	lock_page(page);
 	return page;
 }
diff --git a/fs/Kconfig b/fs/Kconfig
index 7a2b11c0b8036d..05efea674bffa0 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -48,7 +48,6 @@ config FS_DAX
 	bool "File system based Direct Access (DAX) support"
 	depends on MMU
 	depends on !(ARM || MIPS || SPARC)
-	select DEV_PAGEMAP_OPS if (ZONE_DEVICE && !FS_DAX_LIMITED)
 	select FS_IOMAP
 	select DAX
 	help
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 514ab46f597e5c..d6a114dd5ea8b7 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -68,9 +68,9 @@ enum memory_type {
 
 struct dev_pagemap_ops {
 	/*
-	 * Called once the page refcount reaches 1.  (ZONE_DEVICE pages never
-	 * reach 0 refcount unless there is a refcount bug. This allows the
-	 * device driver to implement its own memory management.)
+	 * Called once the page refcount reaches 0.  The reference count will be
+	 * reset to one by the core code after the method is called to prepare
+	 * for handing out the page again.
 	 */
 	void (*page_free)(struct page *page);
 
@@ -133,16 +133,14 @@ static inline unsigned long pgmap_vmemmap_nr(struct
dev_pagemap *pgmap)
 
 static inline bool is_device_private_page(const struct page *page)
 {
-	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
-		IS_ENABLED(CONFIG_DEVICE_PRIVATE) &&
+	return IS_ENABLED(CONFIG_DEVICE_PRIVATE) &&
 		is_zone_device_page(page) &&
 		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
 }
 
 static inline bool is_pci_p2pdma_page(const struct page *page)
 {
-	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
-		IS_ENABLED(CONFIG_PCI_P2PDMA) &&
+	return IS_ENABLED(CONFIG_PCI_P2PDMA) &&
 		is_zone_device_page(page) &&
 		page->pgmap->type == MEMORY_DEVICE_PCI_P2PDMA;
 }
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 80fccfe31c3444..ff9f149ca2017e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1090,7 +1090,7 @@ static inline bool is_zone_movable_page(const struct page
*page)
 	return page_zonenum(page) == ZONE_MOVABLE;
 }
 
-#ifdef CONFIG_DEV_PAGEMAP_OPS
+#if defined(CONFIG_ZONE_DEVICE) && defined(CONFIG_FS_DAX)
 DECLARE_STATIC_KEY_FALSE(devmap_managed_key);
 
 bool __put_devmap_managed_page(struct page *page);
@@ -1103,12 +1103,12 @@ static inline bool put_devmap_managed_page(struct page
*page)
 	return __put_devmap_managed_page(page);
 }
 
-#else /* CONFIG_DEV_PAGEMAP_OPS */
+#else /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
 static inline bool put_devmap_managed_page(struct page *page)
 {
 	return false;
 }
-#endif /* CONFIG_DEV_PAGEMAP_OPS */
+#endif /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
 
 /* 127: arbitrary random number, small enough to assemble well */
 #define folio_ref_zero_or_close_to_overflow(folio) \
diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index e5fc14ba71f33e..cfe63204783918 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -566,7 +566,6 @@ static struct page *dmirror_devmem_alloc_page(struct
dmirror_device *mdevice)
 	}
 
 	dpage->zone_device_data = rpage;
-	get_page(dpage);
 	lock_page(dpage);
 	return dpage;
 
diff --git a/mm/Kconfig b/mm/Kconfig
index 3326ee3903f330..a1901ae6d06293 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -776,9 +776,6 @@ config ZONE_DEVICE
 
 	  If FS_DAX is enabled, then say Y.
 
-config DEV_PAGEMAP_OPS
-	bool
-
 #
 # Helpers to mirror range of the CPU page tables of a process into device page
 # tables.
@@ -790,7 +787,6 @@ config HMM_MIRROR
 config DEVICE_PRIVATE
 	bool "Unaddressable device memory (GPU memory, ...)"
 	depends on ZONE_DEVICE
-	select DEV_PAGEMAP_OPS
 
 	help
 	  Allows creation of struct pages to represent unaddressable device
diff --git a/mm/internal.h b/mm/internal.h
index d80300392a194f..a67222d17e5987 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -718,4 +718,6 @@ void vunmap_range_noflush(unsigned long start, unsigned long
end);
 int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
 		      unsigned long addr, int page_nid, int *flags);
 
+void free_zone_device_page(struct page *page);
+
 #endif	/* __MM_INTERNAL_H */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 09d342c7cbd0d9..d1e97a54ae535e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5503,17 +5503,12 @@ static struct page *mc_handle_swap_pte(struct
vm_area_struct *vma,
 		return NULL;
 
 	/*
-	 * Handle MEMORY_DEVICE_PRIVATE which are ZONE_DEVICE page belonging to
-	 * a device and because they are not accessible by CPU they are store
-	 * as special swap entry in the CPU page table.
+	 * Handle device private pages that are not accessible by the CPU, but
+	 * stored as special swap entries in the page table.
 	 */
 	if (is_device_private_entry(ent)) {
 		page = pfn_swap_entry_to_page(ent);
-		/*
-		 * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have
-		 * a refcount of 1 when free (unlike normal page)
-		 */
-		if (!page_ref_add_unless(page, 1, 1))
+		if (!get_page_unless_zero(page))
 			return NULL;
 		return page;
 	}
diff --git a/mm/memremap.c b/mm/memremap.c
index a0ece2344c2cab..fef5734d5e4933 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -12,6 +12,7 @@
 #include <linux/types.h>
 #include <linux/wait_bit.h>
 #include <linux/xarray.h>
+#include "internal.h"
 
 static DEFINE_XARRAY(pgmap_array);
 
@@ -37,21 +38,19 @@ unsigned long memremap_compat_align(void)
 EXPORT_SYMBOL_GPL(memremap_compat_align);
 #endif
 
-#ifdef CONFIG_DEV_PAGEMAP_OPS
+#ifdef CONFIG_FS_DAX
 DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
 EXPORT_SYMBOL(devmap_managed_key);
 
 static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
 {
-	if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
-	    pgmap->type == MEMORY_DEVICE_FS_DAX)
+	if (pgmap->type == MEMORY_DEVICE_FS_DAX)
 		static_branch_dec(&devmap_managed_key);
 }
 
 static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
 {
-	if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
-	    pgmap->type == MEMORY_DEVICE_FS_DAX)
+	if (pgmap->type == MEMORY_DEVICE_FS_DAX)
 		static_branch_inc(&devmap_managed_key);
 }
 #else
@@ -61,7 +60,7 @@ static void devmap_managed_enable_get(struct dev_pagemap
*pgmap)
 static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
 {
 }
-#endif /* CONFIG_DEV_PAGEMAP_OPS */
+#endif /* CONFIG_FS_DAX */
 
 static void pgmap_array_delete(struct range *range)
 {
@@ -102,23 +101,12 @@ static unsigned long pfn_end(struct dev_pagemap *pgmap,
int range_id)
 	return (range->start + range_len(range)) >> PAGE_SHIFT;
 }
 
-static unsigned long pfn_next(struct dev_pagemap *pgmap, unsigned long pfn)
-{
-	if (pfn % (1024 << pgmap->vmemmap_shift))
-		cond_resched();
-	return pfn + pgmap_vmemmap_nr(pgmap);
-}
-
 static unsigned long pfn_len(struct dev_pagemap *pgmap, unsigned long range_id)
 {
 	return (pfn_end(pgmap, range_id) -
 		pfn_first(pgmap, range_id)) >> pgmap->vmemmap_shift;
 }
 
-#define for_each_device_pfn(pfn, map, i) \
-	for (pfn = pfn_first(map, i); pfn < pfn_end(map, i); \
-	     pfn = pfn_next(map, pfn))
-
 static void pageunmap_range(struct dev_pagemap *pgmap, int range_id)
 {
 	struct range *range = &pgmap->ranges[range_id];
@@ -147,13 +135,11 @@ static void pageunmap_range(struct dev_pagemap *pgmap, int
range_id)
 
 void memunmap_pages(struct dev_pagemap *pgmap)
 {
-	unsigned long pfn;
 	int i;
 
 	percpu_ref_kill(&pgmap->ref);
 	for (i = 0; i < pgmap->nr_range; i++)
-		for_each_device_pfn(pfn, pgmap, i)
-			put_page(pfn_to_page(pfn));
+		percpu_ref_put_many(&pgmap->ref, pfn_len(pgmap, i));
 	wait_for_completion(&pgmap->done);
 	percpu_ref_exit(&pgmap->ref);
 
@@ -464,14 +450,10 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
 }
 EXPORT_SYMBOL_GPL(get_dev_pagemap);
 
-#ifdef CONFIG_DEV_PAGEMAP_OPS
-void free_devmap_managed_page(struct page *page)
+void free_zone_device_page(struct page *page)
 {
-	/* notify page idle for dax */
-	if (!is_device_private_page(page)) {
-		wake_up_var(&page->_refcount);
+	if (WARN_ON_ONCE(!is_device_private_page(page)))
 		return;
-	}
 
 	__ClearPageWaiters(page);
 
@@ -500,28 +482,27 @@ void free_devmap_managed_page(struct page *page)
 	 */
 	page->mapping = NULL;
 	page->pgmap->ops->page_free(page);
+
+	/*
+	 * Reset the page count to 1 to prepare for handing out the page again.
+	 */
+	set_page_count(page, 1);
 }
 
+#ifdef CONFIG_FS_DAX
 bool __put_devmap_managed_page(struct page *page)
 {
-	if (page->pgmap->type != MEMORY_DEVICE_PRIVATE &&
-	    page->pgmap->type != MEMORY_DEVICE_FS_DAX)
+	if (page->pgmap->type != MEMORY_DEVICE_FS_DAX)
 		return false;
 
 	/*
-	 * devmap page refcounts are 1-based, rather than 0-based: if
+	 * fsdax page refcounts are 1-based, rather than 0-based: if
 	 * refcount is 1, then the page is free and the refcount is
 	 * stable because nobody holds a reference on the page.
 	 */
-	switch (page_ref_dec_return(page)) {
-	case 1:
-		free_devmap_managed_page(page);
-		break;
-	case 0:
-		__put_page(page);
-		break;
-	}
+	if (page_ref_dec_return(page) == 1)
+		wake_up_var(&page->_refcount);
 	return true;
 }
 EXPORT_SYMBOL(__put_devmap_managed_page);
-#endif /* CONFIG_DEV_PAGEMAP_OPS */
+#endif /* CONFIG_FS_DAX */
diff --git a/mm/migrate.c b/mm/migrate.c
index c7da064b4781b8..8e0370a73f8a43 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -341,14 +341,8 @@ static int expected_page_refs(struct address_space
*mapping, struct page *page)
 {
 	int expected_count = 1;
 
-	/*
-	 * Device private pages have an extra refcount as they are
-	 * ZONE_DEVICE pages.
-	 */
-	expected_count += is_device_private_page(page);
 	if (mapping)
 		expected_count += compound_nr(page) + page_has_private(page);
-
 	return expected_count;
 }
 
diff --git a/mm/swap.c b/mm/swap.c
index 25b55c56614311..c84d6817043257 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -114,17 +114,9 @@ static void __put_compound_page(struct page *page)
 
 void __put_page(struct page *page)
 {
-	if (is_zone_device_page(page)) {
-		put_dev_pagemap(page->pgmap);
-
-		/*
-		 * The page belongs to the device that created pgmap. Do
-		 * not return it to page allocator.
-		 */
-		return;
-	}
-
-	if (unlikely(PageCompound(page)))
+	if (unlikely(is_zone_device_page(page)))
+		free_zone_device_page(page);
+	else if (unlikely(PageCompound(page)))
 		__put_compound_page(page);
 	else
 		__put_single_page(page);
@@ -933,7 +925,7 @@ void release_pages(struct page **pages, int nr)
 			if (put_devmap_managed_page(page))
 				continue;
 			if (put_page_testzero(page))
-				put_dev_pagemap(page->pgmap);
+				free_zone_device_page(page);
 			continue;
 		}
 
-- 
2.30.2

Christoph Hellwig

2022-Feb-07 06:32 UTC

head link

[Nouveau] [PATCH 8/8] fsdax: depend on ZONE_DEVICE || FS_DAX_LIMITED

Add a depends on ZONE_DEVICE support or the s390-specific limited DAX
support, as one of the two is required at runtime for fsdax code to
actually work.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 fs/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/Kconfig b/fs/Kconfig
index 05efea674bffa0..6e8818a5e53c45 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -48,6 +48,7 @@ config FS_DAX
 	bool "File system based Direct Access (DAX) support"
 	depends on MMU
 	depends on !(ARM || MIPS || SPARC)
+	depends on ZONE_DEVICE || FS_DAX_LIMITED
 	select FS_IOMAP
 	select DAX
 	help
-- 
2.30.2

Logan Gunthorpe

2022-Feb-07 23:51 UTC

head link

[Nouveau] start sorting out the ZONE_DEVICE refcount mess

On 2022-02-06 11:32 p.m., Christoph Hellwig wrote:> Hi all,
> 
> this series removes the offset by one refcount for ZONE_DEVICE pages
> that are freed back to the driver owning them, which is just device
> private ones for now, but also the planned device coherent pages
> and the ehanced p2p ones pending.
> 
> It does not address the fsdax pages yet, which will be attacked in a
> follow on series.
> 
> Diffstat:
>  arch/arm64/mm/mmu.c                      |    1 
>  arch/powerpc/kvm/book3s_hv_uvmem.c       |    1 
>  drivers/gpu/drm/amd/amdkfd/kfd_migrate.c |    2 
>  drivers/gpu/drm/amd/amdkfd/kfd_priv.h    |    1 
>  drivers/gpu/drm/drm_cache.c              |    2 
>  drivers/gpu/drm/nouveau/nouveau_dmem.c   |    3 -
>  drivers/gpu/drm/nouveau/nouveau_svm.c    |    1 
>  drivers/infiniband/core/rw.c             |    1 
>  drivers/nvdimm/pmem.h                    |    1 
>  drivers/nvme/host/pci.c                  |    1 
>  drivers/nvme/target/io-cmd-bdev.c        |    1 
>  fs/Kconfig                               |    2 
>  fs/fuse/virtio_fs.c                      |    1 
>  include/linux/hmm.h                      |    9 ----
>  include/linux/memremap.h                 |   22 +++++++++-
>  include/linux/mm.h                       |   59
++++-------------------------
>  lib/test_hmm.c                           |    4 +
>  mm/Kconfig                               |    4 -
>  mm/internal.h                            |    2 
>  mm/memcontrol.c                          |   11 +----
>  mm/memremap.c                            |   63
++++++++++++++++---------------
>  mm/migrate.c                             |    6 --
>  mm/swap.c                                |   49 ++----------------------
>  23 files changed, 90 insertions(+), 157 deletions(-)
Looks good to me. I was wondering about the location of some of this
code, so it's nice to see it cleaned up. Except for the one minor issue
I noted on patch 6, it all looks good to me. I've reviewed all the
patches and tested the series under my p2pdma series.

Reviewed-by: Logan Gunthorpe <logang at deltatee.com>

Logan

Miaohe Lin

2022-Feb-08 03:03 UTC

head link

[Nouveau] start sorting out the ZONE_DEVICE refcount mess

On 2022/2/7 14:32, Christoph Hellwig wrote:> Hi all,
> 
> this series removes the offset by one refcount for ZONE_DEVICE pages
> that are freed back to the driver owning them, which is just device
> private ones for now, but also the planned device coherent pages
> and the ehanced p2p ones pending.
> 
Many thanks for doing this, I remember the hard time when I read the relevant
code. :)
> It does not address the fsdax pages yet, which will be attacked in a
> follow on series.
> 
> Diffstat:
>  arch/arm64/mm/mmu.c                      |    1 
>  arch/powerpc/kvm/book3s_hv_uvmem.c       |    1 
>  drivers/gpu/drm/amd/amdkfd/kfd_migrate.c |    2 
>  drivers/gpu/drm/amd/amdkfd/kfd_priv.h    |    1 
>  drivers/gpu/drm/drm_cache.c              |    2 
>  drivers/gpu/drm/nouveau/nouveau_dmem.c   |    3 -
>  drivers/gpu/drm/nouveau/nouveau_svm.c    |    1 
>  drivers/infiniband/core/rw.c             |    1 
>  drivers/nvdimm/pmem.h                    |    1 
>  drivers/nvme/host/pci.c                  |    1 
>  drivers/nvme/target/io-cmd-bdev.c        |    1 
>  fs/Kconfig                               |    2 
>  fs/fuse/virtio_fs.c                      |    1 
>  include/linux/hmm.h                      |    9 ----
>  include/linux/memremap.h                 |   22 +++++++++-
>  include/linux/mm.h                       |   59
++++-------------------------
>  lib/test_hmm.c                           |    4 +
>  mm/Kconfig                               |    4 -
>  mm/internal.h                            |    2 
>  mm/memcontrol.c                          |   11 +----
>  mm/memremap.c                            |   63
++++++++++++++++---------------
>  mm/migrate.c                             |    6 --
>  mm/swap.c                                |   49 ++----------------------
>  23 files changed, 90 insertions(+), 157 deletions(-)
> 
> .
>

Nouveau - Feb 2022 - start sorting out the ZONE_DEVICE refcount mess

[Nouveau] start sorting out the ZONE_DEVICE refcount mess

[Nouveau] [PATCH 1/8] mm: remove a pointless CONFIG_ZONE_DEVICE check in memremap_pages

[Nouveau] [PATCH 2/8] mm: remove the __KERNEL__ guard from <linux/mm.h>

[Nouveau] [PATCH 3/8] mm: remove pointless includes from <linux/hmm.h>

[Nouveau] [PATCH 4/8] mm: move free_devmap_managed_page to memremap.c

[Nouveau] [PATCH 5/8] mm: simplify freeing of devmap managed pages

[Nouveau] [PATCH 6/8] mm: don't include <linux/memremap.h> in <linux/mm.h>

[Nouveau] [PATCH 7/8] mm: remove the extra ZONE_DEVICE struct page refcount

[Nouveau] [PATCH 8/8] fsdax: depend on ZONE_DEVICE || FS_DAX_LIMITED

[Nouveau] start sorting out the ZONE_DEVICE refcount mess

[Nouveau] start sorting out the ZONE_DEVICE refcount mess

[Nouveau] [PATCH 2/8] mm: remove the KERNEL guard from <linux/mm.h>