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authorDan Williams2018-05-16 11:46:08 -0700
committerDan Williams2018-05-22 06:59:39 -0700
commite7638488434415aa478e78435cac8f0365737638 (patch)
tree7ce50f0ed69889aa44cb0124451cf7a56b34eba6 /include/linux/mm.h
parent5981690ddb8f72f9546a2d017a914cf56095fc1f (diff)
mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS
In preparation for fixing dax-dma-vs-unmap issues, filesystems need to be able to rely on the fact that they will get wakeups on dev_pagemap page-idle events. Introduce MEMORY_DEVICE_FS_DAX and generic_dax_page_free() as common indicator / infrastructure for dax filesytems to require. With this change there are no users of the MEMORY_DEVICE_HOST designation, so remove it. The HMM sub-system extended dev_pagemap to arrange a callback when a dev_pagemap managed page is freed. Since a dev_pagemap page is free / idle when its reference count is 1 it requires an additional branch to check the page-type at put_page() time. Given put_page() is a hot-path we do not want to incur that check if HMM is not in use, so a static branch is used to avoid that overhead when not necessary. Now, the FS_DAX implementation wants to reuse this mechanism for receiving dev_pagemap ->page_free() callbacks. Rework the HMM-specific static-key into a generic mechanism that either HMM or FS_DAX code paths can enable. For ARCH=um builds, and any other arch that lacks ZONE_DEVICE support, care must be taken to compile out the DEV_PAGEMAP_OPS infrastructure. However, we still need to support FS_DAX in the FS_DAX_LIMITED case implemented by the s390/dcssblk driver. Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Reported-by: kbuild test robot <lkp@intel.com> Reported-by: Thomas Meyer <thomas@m3y3r.de> Reported-by: Dave Jiang <dave.jiang@intel.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'include/linux/mm.h')
-rw-r--r--include/linux/mm.h71
1 files changed, 53 insertions, 18 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1ac1f06a4be6..6e19265ee8f8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -821,27 +821,65 @@ static inline bool is_zone_device_page(const struct page *page)
}
#endif
-#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC)
-void put_zone_device_private_or_public_page(struct page *page);
-DECLARE_STATIC_KEY_FALSE(device_private_key);
-#define IS_HMM_ENABLED static_branch_unlikely(&device_private_key)
-static inline bool is_device_private_page(const struct page *page);
-static inline bool is_device_public_page(const struct page *page);
-#else /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
-static inline void put_zone_device_private_or_public_page(struct page *page)
+#ifdef CONFIG_DEV_PAGEMAP_OPS
+void dev_pagemap_get_ops(void);
+void dev_pagemap_put_ops(void);
+void __put_devmap_managed_page(struct page *page);
+DECLARE_STATIC_KEY_FALSE(devmap_managed_key);
+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_PUBLIC:
+ case MEMORY_DEVICE_FS_DAX:
+ __put_devmap_managed_page(page);
+ return true;
+ default:
+ break;
+ }
+ return false;
+}
+
+static inline bool is_device_private_page(const struct page *page)
{
+ return is_zone_device_page(page) &&
+ page->pgmap->type == MEMORY_DEVICE_PRIVATE;
}
-#define IS_HMM_ENABLED 0
+
+static inline bool is_device_public_page(const struct page *page)
+{
+ return is_zone_device_page(page) &&
+ page->pgmap->type == MEMORY_DEVICE_PUBLIC;
+}
+
+#else /* CONFIG_DEV_PAGEMAP_OPS */
+static inline void dev_pagemap_get_ops(void)
+{
+}
+
+static inline void dev_pagemap_put_ops(void)
+{
+}
+
+static inline bool put_devmap_managed_page(struct page *page)
+{
+ return false;
+}
+
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;
}
-#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
-
+#endif /* CONFIG_DEV_PAGEMAP_OPS */
static inline void get_page(struct page *page)
{
@@ -859,16 +897,13 @@ static inline void put_page(struct page *page)
page = compound_head(page);
/*
- * For private device pages we need to catch refcount transition from
- * 2 to 1, when refcount reach one it means the private device page is
- * free and we need to inform the device driver through callback. See
+ * 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.
*/
- if (IS_HMM_ENABLED && unlikely(is_device_private_page(page) ||
- unlikely(is_device_public_page(page)))) {
- put_zone_device_private_or_public_page(page);
+ if (put_devmap_managed_page(page))
return;
- }
if (put_page_testzero(page))
__put_page(page);