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authorDan Williams <dan.j.williams@intel.com>2018-05-16 11:46:08 -0700
committerDan Williams <dan.j.williams@intel.com>2018-05-22 06:59:39 -0700
commite7638488434415aa478e78435cac8f0365737638 (patch)
tree7ce50f0ed69889aa44cb0124451cf7a56b34eba6 /mm/hmm.c
parent5981690ddb8f72f9546a2d017a914cf56095fc1f (diff)
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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 'mm/hmm.c')
-rw-r--r--mm/hmm.c13
1 files changed, 2 insertions, 11 deletions
diff --git a/mm/hmm.c b/mm/hmm.c
index 486dc394a5a3..de7b6bf77201 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -35,15 +35,6 @@
#define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT)
-#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC)
-/*
- * Device private memory see HMM (Documentation/vm/hmm.txt) or hmm.h
- */
-DEFINE_STATIC_KEY_FALSE(device_private_key);
-EXPORT_SYMBOL(device_private_key);
-#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
-
-
#if IS_ENABLED(CONFIG_HMM_MIRROR)
static const struct mmu_notifier_ops hmm_mmu_notifier_ops;
@@ -1167,7 +1158,7 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
resource_size_t addr;
int ret;
- static_branch_enable(&device_private_key);
+ dev_pagemap_get_ops();
devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem),
GFP_KERNEL, dev_to_node(device));
@@ -1261,7 +1252,7 @@ struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY)
return ERR_PTR(-EINVAL);
- static_branch_enable(&device_private_key);
+ dev_pagemap_get_ops();
devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem),
GFP_KERNEL, dev_to_node(device));