search for: need_devmap_managed

...p->altmap.alloc, "failed to free all reserved pages\n"); - devmap_managed_enable_put(); } EXPORT_SYMBOL_GPL(memunmap_pages); @@ -319,7 +289,6 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) .pgprot = PAGE_KERNEL, }; const int nr_range = pgmap->nr_range; - bool need_devmap_managed = true; int error, i; if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) @@ -331,8 +300,9 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) WARN(1, "Device private memory not supported\n"); return ERR_PTR(-EINVAL); } - if (!pgmap->ops || !pg...

...ed pages\n"); > - devmap_managed_enable_put(); > } > EXPORT_SYMBOL_GPL(memunmap_pages); > > @@ -319,7 +289,6 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > .pgprot = PAGE_KERNEL, > }; > const int nr_range = pgmap->nr_range; > - bool need_devmap_managed = true; > int error, i; > > if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) > @@ -331,8 +300,9 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > WARN(1, "Device private memory not supported\n"); > return ERR_PTR(-EINVAL)...

..._managed_enable_put(); + if (pgmap->type == MEMORY_DEVICE_FS_DAX) + devmap_managed_enable_put(); } EXPORT_SYMBOL_GPL(memunmap_pages); @@ -328,7 +312,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) .pgprot = PAGE_KERNEL, }; const int nr_range = pgmap->nr_range; - bool need_devmap_managed = true; + bool need_devmap_managed = false; int error, i; if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) @@ -344,6 +328,10 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) WARN(1, "Missing migrate_to_ram method\n"); return ERR_PTR(-EINVAL);...

...#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, unsigned long addr, @@ -156,6 +185,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) }; pgprot_t pgprot = PAGE_KERNEL; int error, nid, is_ram; + bool need_devmap_managed = true; switch (pgmap->type) { case MEMORY_DEVICE_PRIVATE: @@ -173,6 +203,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) break; case MEMORY_DEVICE_DEVDAX: case MEMORY_DEVICE_PCI_P2PDMA: + need_devmap_managed = false; break; default: WARN(1, &q...

..._managed_enable_put(); + if (pgmap->type == MEMORY_DEVICE_FS_DAX) + devmap_managed_enable_put(); } EXPORT_SYMBOL_GPL(memunmap_pages); @@ -328,7 +312,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) .pgprot = PAGE_KERNEL, }; const int nr_range = pgmap->nr_range; - bool need_devmap_managed = true; + bool need_devmap_managed = false; int error, i; if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) @@ -344,6 +328,10 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) WARN(1, "Missing migrate_to_ram method\n"); return ERR_PTR(-EINVAL);...

...TE) > vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, > unsigned long addr, > @@ -156,6 +185,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) > }; > pgprot_t pgprot = PAGE_KERNEL; > int error, nid, is_ram; > + bool need_devmap_managed = true; > > switch (pgmap->type) { > case MEMORY_DEVICE_PRIVATE: > @@ -173,6 +203,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) > break; > case MEMORY_DEVICE_DEVDAX: > case MEMORY_DEVICE_PCI_P2PDMA: > + need_devmap_managed = f...

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. Signed-off-by: Ralph Campbell <rcampbell at

...res); WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n"); - devmap_managed_enable_put(); } EXPORT_SYMBOL_GPL(memunmap_pages); @@ -192,7 +147,6 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) .pgprot = PAGE_KERNEL, }; int error, is_ram; - bool need_devmap_managed = true; switch (pgmap->type) { case MEMORY_DEVICE_PRIVATE: @@ -217,11 +171,9 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) } break; case MEMORY_DEVICE_GENERIC: - need_devmap_managed = false; break; case MEMORY_DEVICE_PCI_P2PDMA: params.pgprot = pgprot_noncach...

...p->altmap.alloc, "failed to free all reserved pages\n"); - devmap_managed_enable_put(); } EXPORT_SYMBOL_GPL(memunmap_pages); @@ -327,7 +286,6 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) .pgprot = PAGE_KERNEL, }; const int nr_range = pgmap->nr_range; - bool need_devmap_managed = true; int error, i; if (WARN_ONCE(!nr_range, "nr_range must be specified\n")) @@ -343,6 +301,10 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) WARN(1, "Missing migrate_to_ram method\n"); return ERR_PTR(-EINVAL); } + if (!pgmap->ops->page_fr...

Matthew Wilcox, Ira Weiny, and others have complained that ZONE_DEVICE struct page reference counting is ugly because they are "free" when the reference count is one instead of zero. This leads to explicit checks for ZONE_DEVICE pages in places like put_page(), GUP, THP splitting, and page migration which have to adjust the expected reference count when determining if the page is

...; > dpage->zone_device_data = rpage; > - get_page(dpage); > + init_page_count(dpage); > lock_page(dpage); > return dpage; > Doesn't test_hmm also need to reinitialize the refcount before freeing the page in hmm_dmirror_exit? > int error, is_ram; > - bool need_devmap_managed = true; > > switch (pgmap->type) { > case MEMORY_DEVICE_PRIVATE: > @@ -217,11 +171,9 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid) > } > break; > case MEMORY_DEVICE_GENERIC: The MEMORY_DEVICE_PRIVATE cases loses the sanity check that the page_fre...

This is still an RFC because after looking at the pmem/dax code some more, I realized that the ZONE_DEVICE struct pages are being inserted into the process' page tables with vmf_insert_mixed() and a zero refcount on the ZONE_DEVICE struct page. This is sort of OK because insert_pfn() increments the reference count on the pgmap which is what prevents memunmap_pages() from freeing the struct

...+ if (error) + return ERR_PTR(error); + pgmap->ref = &pgmap->internal_ref; + } else { + if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) { + WARN(1, "Missing reference count teardown definition\n"); + return ERR_PTR(-EINVAL); + } } if (need_devmap_managed) { @@ -296,8 +334,8 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) err_pfn_remap: pgmap_array_delete(res); err_array: - pgmap->ops->kill(pgmap); - pgmap->ops->cleanup(pgmap); + dev_pagemap_kill(pgmap); + dev_pagemap_cleanup(pgmap); return ERR_PTR(err...

...g reference count teardown definition\n"); > + return ERR_PTR(-EINVAL); > + } After this series are there any users who continue to supply their own reference object and these callbacks? As it stands: Reviewed-by: Ira Weiny <ira.weiny at intel.com> > } > > if (need_devmap_managed) { > @@ -296,8 +334,8 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) > err_pfn_remap: > pgmap_array_delete(res); > err_array: > - pgmap->ops->kill(pgmap); > - pgmap->ops->cleanup(pgmap); > + dev_pagemap_kill(pgmap); > + dev_page...

Hi Dan, Jérôme and Jason, below is a series that cleans up the dev_pagemap interface so that it is more easily usable, which removes the need to wrap it in hmm and thus allowing to kill a lot of code Note: this series is on top of Linux 5.2-rc5 and has some minor conflicts with the hmm tree that are easy to resolve. Diffstat summary: 32 files changed, 361 insertions(+), 1012 deletions(-) Git