[PATCH 04/25] mm: remove MEMORY_DEVICE_PUBLIC support

Christoph Hellwig
2019-06-26T12:27:49Z

The code hasn't been used since it was added to the tree, and doesn't
appear to actually be usable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Michal Hocko <mhocko@suse.com>
---
include/linux/hmm.h | 4 ++--
include/linux/ioport.h | 1 -
include/linux/memremap.h | 8 --------
include/linux/mm.h | 12 ------------
mm/Kconfig | 11 -----------
mm/gup.c | 7 -------
mm/hmm.c | 4 ++--
mm/memcontrol.c | 11 +++++------
mm/memory-failure.c | 6 +-----
mm/memory.c | 34 ----------------------------------
mm/migrate.c | 26 +++-----------------------
mm/swap.c | 11 -----------
12 files changed, 13 insertions(+), 122 deletions(-)

diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index 5c46b0f603fd..44a5ac738bb5 100644
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -584,7 +584,7 @@ static inline void hmm_mm_destroy(struct mm_struct *mm) {}
static inline void hmm_mm_init(struct mm_struct *mm) {}
#endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */

-#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC)
+#if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
struct hmm_devmem;

struct page *hmm_vma_alloc_locked_page(struct vm_area_struct *vma,
@@ -748,7 +748,7 @@ static inline unsigned long hmm_devmem_page_get_drvdata(const struct page *page)
{
return page->hmm_data;
}
-#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
+#endif /* CONFIG_DEVICE_PRIVATE */
#else /* IS_ENABLED(CONFIG_HMM) */
static inline void hmm_mm_destroy(struct mm_struct *mm) {}
static inline void hmm_mm_init(struct mm_struct *mm) {}
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index da0ebaec25f0..dd961882bc74 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -132,7 +132,6 @@ enum {
IORES_DESC_PERSISTENT_MEMORY = 4,
IORES_DESC_PERSISTENT_MEMORY_LEGACY = 5,
IORES_DESC_DEVICE_PRIVATE_MEMORY = 6,
- IORES_DESC_DEVICE_PUBLIC_MEMORY = 7,
};

/* helpers to define resources */
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 1732dea030b2..995c62c5a48b 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -37,13 +37,6 @@ struct vmem_altmap {
* A more complete discussion of unaddressable memory may be found in
* include/linux/hmm.h and Documentation/vm/hmm.rst.
*
- * MEMORY_DEVICE_PUBLIC:
- * Device memory that is cache coherent from device and CPU point of view. This
- * is use on platform that have an advance system bus (like CAPI or CCIX). A
- * driver can hotplug the device memory using ZONE_DEVICE and with that memory
- * type. Any page of a process can be migrated to such memory. However no one
- * should be allow to pin such memory so that it can always be evicted.
- *
* MEMORY_DEVICE_FS_DAX:
* Host memory that has similar access semantics as System RAM i.e. DMA
* coherent and supports page pinning. In support of coordinating page
@@ -58,7 +51,6 @@ struct vmem_altmap {
*/
enum memory_type {
MEMORY_DEVICE_PRIVATE = 1,
- MEMORY_DEVICE_PUBLIC,
MEMORY_DEVICE_FS_DAX,
MEMORY_DEVICE_PCI_P2PDMA,
};
diff --git a/include/linux/mm.h b/include/linux/mm.h
index dd0b5f4e1e45..6e4b9be08b13 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -944,7 +944,6 @@ static inline bool put_devmap_managed_page(struct page *page)
return false;
switch (page->pgmap->type) {
case MEMORY_DEVICE_PRIVATE:
- case MEMORY_DEVICE_PUBLIC:
case MEMORY_DEVICE_FS_DAX:
__put_devmap_managed_page(page);
return true;
@@ -960,12 +959,6 @@ static inline bool is_device_private_page(const struct page *page)
page->pgmap->type == MEMORY_DEVICE_PRIVATE;
}

-static inline bool is_device_public_page(const struct page *page)
-{
- return is_zone_device_page(page) &&
- page->pgmap->type == MEMORY_DEVICE_PUBLIC;
-}
-
#ifdef CONFIG_PCI_P2PDMA
static inline bool is_pci_p2pdma_page(const struct page *page)
{
@@ -998,11 +991,6 @@ static inline bool is_device_private_page(const struct page *page)
return false;
}

-static inline bool is_device_public_page(const struct page *page)
-{
- return false;
-}
-
static inline bool is_pci_p2pdma_page(const struct page *page)
{
return false;
diff --git a/mm/Kconfig b/mm/Kconfig
index 0d2ba7e1f43e..6f35b85b3052 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -718,17 +718,6 @@ config DEVICE_PRIVATE
memory; i.e., memory that is only accessible from the device (or
group of devices). You likely also want to select HMM_MIRROR.

-config DEVICE_PUBLIC
- bool "Addressable device memory (like GPU memory)"
- depends on ARCH_HAS_HMM
- select HMM
- select DEV_PAGEMAP_OPS
-
- help
- Allows creation of struct pages to represent addressable device
- memory; i.e., memory that is accessible from both the device and
- the CPU
-
config FRAME_VECTOR
bool

diff --git a/mm/gup.c b/mm/gup.c
index ddde097cf9e4..fe131d879c70 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -605,13 +605,6 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address,
if ((gup_flags & FOLL_DUMP) || !is_zero_pfn(pte_pfn(*pte)))
goto unmap;
*page = pte_page(*pte);
-
- /*
- * This should never happen (a device public page in the gate
- * area).
- */
- if (is_device_public_page(*page))
- goto unmap;
}
if (unlikely(!try_get_page(*page))) {
ret = -ENOMEM;
diff --git a/mm/hmm.c b/mm/hmm.c
index bd260a3b6b09..376159a769fb 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -1331,7 +1331,7 @@ EXPORT_SYMBOL(hmm_range_dma_unmap);
#endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */

-#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC)
+#if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
struct page *hmm_vma_alloc_locked_page(struct vm_area_struct *vma,
unsigned long addr)
{
@@ -1478,4 +1478,4 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
return devmem;
}
EXPORT_SYMBOL_GPL(hmm_devmem_add);
-#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
+#endif /* CONFIG_DEVICE_PRIVATE */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ba9138a4a1de..fa844ae85bce 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4994,8 +4994,8 @@ static int mem_cgroup_move_account(struct page *page,
* 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
* target for charge migration. if @target is not NULL, the entry is stored
* in target->ent.
- * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PUBLIC
- * or MEMORY_DEVICE_PRIVATE (so ZONE_DEVICE page and thus not on the lru).
+ * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PRIVATE
+ * (so ZONE_DEVICE page and thus not on the lru).
* For now we such page is charge like a regular page would be as for all
* intent and purposes it is just special memory taking the place of a
* regular page.
@@ -5029,8 +5029,7 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
*/
if (page->mem_cgroup == mc.from) {
ret = MC_TARGET_PAGE;
- if (is_device_private_page(page) ||
- is_device_public_page(page))
+ if (is_device_private_page(page))
ret = MC_TARGET_DEVICE;
if (target)
target->page = page;
@@ -5101,8 +5100,8 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
if (ptl) {
/*
* Note their can not be MC_TARGET_DEVICE for now as we do not
- * support transparent huge page with MEMORY_DEVICE_PUBLIC or
- * MEMORY_DEVICE_PRIVATE but this might change.
+ * support transparent huge page with MEMORY_DEVICE_PRIVATE but
+ * this might change.
*/
if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
mc.precharge += HPAGE_PMD_NR;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 8da0334b9ca0..d9fc1a8bdf6a 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1177,16 +1177,12 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
goto unlock;
}

- switch (pgmap->type) {
- case MEMORY_DEVICE_PRIVATE:
- case MEMORY_DEVICE_PUBLIC:
+ if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
/*
* TODO: Handle HMM pages which may need coordination
* with device-side memory.
*/
goto unlock;
- default:
- break;
}

/*
diff --git a/mm/memory.c b/mm/memory.c
index ddf20bd0c317..bd21e7063bf0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -585,29 +585,6 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
return NULL;
if (is_zero_pfn(pfn))
return NULL;
-
- /*
- * Device public pages are special pages (they are ZONE_DEVICE
- * pages but different from persistent memory). They behave
- * allmost like normal pages. The difference is that they are
- * not on the lru and thus should never be involve with any-
- * thing that involve lru manipulation (mlock, numa balancing,
- * ...).
- *
- * This is why we still want to return NULL for such page from
- * vm_normal_page() so that we do not have to special case all
- * call site of vm_normal_page().
- */
- if (likely(pfn <= highest_memmap_pfn)) {
- struct page *page = pfn_to_page(pfn);
-
- if (is_device_public_page(page)) {
- if (with_public_device)
- return page;
- return NULL;
- }
- }
-
if (pte_devmap(pte))
return NULL;

@@ -797,17 +774,6 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
rss[mm_counter(page)]++;
} else if (pte_devmap(pte)) {
page = pte_page(pte);
-
- /*
- * Cache coherent device memory behave like regular page and
- * not like persistent memory page. For more informations see
- * MEMORY_DEVICE_CACHE_COHERENT in memory_hotplug.h
- */
- if (is_device_public_page(page)) {
- get_page(page);
- page_dup_rmap(page, false);
- rss[mm_counter(page)]++;
- }
}

out_set_pte:
diff --git a/mm/migrate.c b/mm/migrate.c
index f2ecc2855a12..149c692d5f9b 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -246,8 +246,6 @@ static bool remove_migration_pte(struct page *page, struct vm_area_struct *vma,
if (is_device_private_page(new)) {
entry = make_device_private_entry(new, pte_write(pte));
pte = swp_entry_to_pte(entry);
- } else if (is_device_public_page(new)) {
- pte = pte_mkdevmap(pte);
}
}

@@ -381,7 +379,6 @@ static int expected_page_refs(struct address_space *mapping, struct page *page)
* ZONE_DEVICE pages.
*/
expected_count += is_device_private_page(page);
- expected_count += is_device_public_page(page);
if (mapping)
expected_count += hpage_nr_pages(page) + page_has_private(page);

@@ -994,10 +991,7 @@ static int move_to_new_page(struct page *newpage, struct page *page,
if (!PageMappingFlags(page))
page->mapping = NULL;

- if (unlikely(is_zone_device_page(newpage))) {
- if (is_device_public_page(newpage))
- flush_dcache_page(newpage);
- } else
+ if (likely(!is_zone_device_page(newpage)))
flush_dcache_page(newpage);

}
@@ -2406,16 +2400,7 @@ static bool migrate_vma_check_page(struct page *page)
* FIXME proper solution is to rework migration_entry_wait() so
* it does not need to take a reference on page.
*/
- if (is_device_private_page(page))
- return true;
-
- /*
- * Only allow device public page to be migrated and account for
- * the extra reference count imply by ZONE_DEVICE pages.
- */
- if (!is_device_public_page(page))
- return false;
- extra++;
+ return is_device_private_page(page);
}

/* For file back page */
@@ -2665,11 +2650,6 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,

swp_entry = make_device_private_entry(page, vma->vm_flags & VM_WRITE);
entry = swp_entry_to_pte(swp_entry);
- } else if (is_device_public_page(page)) {
- entry = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot)));
- if (vma->vm_flags & VM_WRITE)
- entry = pte_mkwrite(pte_mkdirty(entry));
- entry = pte_mkdevmap(entry);
}
} else {
entry = mk_pte(page, vma->vm_page_prot);
@@ -2789,7 +2769,7 @@ static void migrate_vma_pages(struct migrate_vma *migrate)
migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
continue;
}
- } else if (!is_device_public_page(newpage)) {
+ } else {
/*
* Other types of ZONE_DEVICE page are not
* supported.
diff --git a/mm/swap.c b/mm/swap.c
index 7ede3eddc12a..83107410d29f 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -740,17 +740,6 @@ void release_pages(struct page **pages, int nr)
if (is_huge_zero_page(page))
continue;

- /* Device public page can not be huge page */
- if (is_device_public_page(page)) {
- if (locked_pgdat) {
- spin_unlock_irqrestore(&locked_pgdat->lru_lock,
- flags);
- locked_pgdat = NULL;
- }
- put_devmap_managed_page(page);
- continue;
- }
-
page = compound_head(page);
if (!put_page_testzero(page))
continue;
--
2.20.1