From: John Hubbard <jhubbard@nvidia.com> To: Andrew Morton <akpm@linux-foundation.org> Cc: "Al Viro" <viro@zeniv.linux.org.uk>, "Alex Williamson" <alex.williamson@redhat.com>, "Benjamin Herrenschmidt" <benh@kernel.crashing.org>, "Björn Töpel" <bjorn.topel@intel.com>, "Christoph Hellwig" <hch@infradead.org>, "Dan Williams" <dan.j.williams@intel.com>, "Daniel Vetter" <daniel@ffwll.ch>, "Dave Chinner" <david@fromorbit.com>, "David Airlie" <airlied@linux.ie>, "David S . Miller" <davem@davemloft.net>, "Ira Weiny" <ira.weiny@intel.com>, "Jan Kara" <jack@suse.cz>, "Jason Gunthorpe" <jgg@ziepe.ca>, "Jens Axboe" <axboe@kernel.dk>, "Jonathan Corbet" <corbet@lwn.net>, "Jérôme Glisse" <jglisse@redhat.com>, "Magnus Karlsson" <magnus.karlsson@intel.com>, "Mauro Carvalho Chehab" <mchehab@kernel.org>, "Michael Ellerman" <mpe@ellerman.id.au> Subject: [PATCH v5 05/24] mm: devmap: refactor 1-based refcounting for ZONE_DEVICE pages Date: Thu, 14 Nov 2019 21:53:21 -0800 [thread overview] Message-ID: <20191115055340.1825745-6-jhubbard@nvidia.com> (raw) In-Reply-To: <20191115055340.1825745-1-jhubbard@nvidia.com> An upcoming patch changes and complicates the refcounting and especially the "put page" aspects of it. In order to keep everything clean, refactor the devmap page release routines: * Rename put_devmap_managed_page() to page_is_devmap_managed(), and limit the functionality to "read only": return a bool, with no side effects. * Add a new routine, put_devmap_managed_page(), to handle checking what kind of page it is, and what kind of refcount handling it requires. * Rename __put_devmap_managed_page() to free_devmap_managed_page(), and limit the functionality to unconditionally freeing a devmap page. This is originally based on a separate patch by Ira Weiny, which applied to an early version of the put_user_page() experiments. Since then, Jérôme Glisse suggested the refactoring described above. Cc: Jan Kara <jack@suse.cz> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Suggested-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: John Hubbard <jhubbard@nvidia.com> --- include/linux/mm.h | 27 ++++++++++++++++++++++++--- mm/memremap.c | 16 ++-------------- 2 files changed, 26 insertions(+), 17 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index a2adf95b3f9c..96228376139c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -967,9 +967,10 @@ static inline bool is_zone_device_page(const struct page *page) #endif #ifdef CONFIG_DEV_PAGEMAP_OPS -void __put_devmap_managed_page(struct page *page); +void free_devmap_managed_page(struct page *page); DECLARE_STATIC_KEY_FALSE(devmap_managed_key); -static inline bool put_devmap_managed_page(struct page *page) + +static inline bool page_is_devmap_managed(struct page *page) { if (!static_branch_unlikely(&devmap_managed_key)) return false; @@ -978,7 +979,6 @@ static inline bool put_devmap_managed_page(struct page *page) switch (page->pgmap->type) { case MEMORY_DEVICE_PRIVATE: case MEMORY_DEVICE_FS_DAX: - __put_devmap_managed_page(page); return true; default: break; @@ -986,6 +986,27 @@ static inline bool put_devmap_managed_page(struct page *page) return false; } +static inline bool put_devmap_managed_page(struct page *page) +{ + bool is_devmap = page_is_devmap_managed(page); + + if (is_devmap) { + int 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); + } + + return is_devmap; +} + #else /* CONFIG_DEV_PAGEMAP_OPS */ static inline bool put_devmap_managed_page(struct page *page) { diff --git a/mm/memremap.c b/mm/memremap.c index e899fa876a62..2ba773859031 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -411,20 +411,8 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn, EXPORT_SYMBOL_GPL(get_dev_pagemap); #ifdef CONFIG_DEV_PAGEMAP_OPS -void __put_devmap_managed_page(struct page *page) +void free_devmap_managed_page(struct page *page) { - int count = page_ref_dec_return(page); - - /* still busy */ - if (count > 1) - return; - - /* only triggered by the dev_pagemap shutdown path */ - if (count == 0) { - __put_page(page); - return; - } - /* notify page idle for dax */ if (!is_device_private_page(page)) { wake_up_var(&page->_refcount); @@ -461,5 +449,5 @@ void __put_devmap_managed_page(struct page *page) page->mapping = NULL; page->pgmap->ops->page_free(page); } -EXPORT_SYMBOL(__put_devmap_managed_page); +EXPORT_SYMBOL(free_devmap_managed_page); #endif /* CONFIG_DEV_PAGEMAP_OPS */ -- 2.24.0
WARNING: multiple messages have this Message-ID (diff)
From: John Hubbard <jhubbard@nvidia.com> To: Andrew Morton <akpm@linux-foundation.org> Cc: "Michal Hocko" <mhocko@suse.com>, "Jan Kara" <jack@suse.cz>, kvm@vger.kernel.org, linux-doc@vger.kernel.org, "David Airlie" <airlied@linux.ie>, "Dave Chinner" <david@fromorbit.com>, dri-devel@lists.freedesktop.org, LKML <linux-kernel@vger.kernel.org>, linux-mm@kvack.org, "Paul Mackerras" <paulus@samba.org>, linux-kselftest@vger.kernel.org, "Ira Weiny" <ira.weiny@intel.com>, "Christoph Hellwig" <hch@lst.de>, "Jonathan Corbet" <corbet@lwn.net>, linux-rdma@vger.kernel.org, "Michael Ellerman" <mpe@ellerman.id.au>, "Christoph Hellwig" <hch@infradead.org>, "Jason Gunthorpe" <jgg@ziepe.ca>, "Vlastimil Babka" <vbabka@suse.cz>, "Björn Töpel" <bjorn.topel@intel.com>, linux-media@vger.kernel.org, "Shuah Khan" <shuah@kernel.org>, "John Hubbard" <jhubbard@nvidia.com>, linux-block@vger.kernel.org, "Jérôme Glisse" <jglisse@redhat.com>, "Al Viro" <viro@zeniv.linux.org.uk>, "Dan Williams" <dan.j.williams@intel.com>, "Mauro Carvalho Chehab" <mchehab@kernel.org>, "Magnus Karlsson" <magnus.karlsson@intel.com>, "Jens Axboe" <axboe@kernel.dk>, netdev@vger.kernel.org, "Alex Williamson" <alex.williamson@redhat.com>, linux-fsdevel@vger.kernel.org, bpf@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, "David S . Miller" <davem@davemloft.net>, "Mike Kravetz" <mike.kravetz@oracle.com> Subject: [PATCH v5 05/24] mm: devmap: refactor 1-based refcounting for ZONE_DEVICE pages Date: Thu, 14 Nov 2019 21:53:21 -0800 [thread overview] Message-ID: <20191115055340.1825745-6-jhubbard@nvidia.com> (raw) Message-ID: <20191115055321.OejIt6R5tjVAfdEdQsIRU2NOW5yoAI0yqAUfIpt1vn0@z> (raw) In-Reply-To: <20191115055340.1825745-1-jhubbard@nvidia.com> An upcoming patch changes and complicates the refcounting and especially the "put page" aspects of it. In order to keep everything clean, refactor the devmap page release routines: * Rename put_devmap_managed_page() to page_is_devmap_managed(), and limit the functionality to "read only": return a bool, with no side effects. * Add a new routine, put_devmap_managed_page(), to handle checking what kind of page it is, and what kind of refcount handling it requires. * Rename __put_devmap_managed_page() to free_devmap_managed_page(), and limit the functionality to unconditionally freeing a devmap page. This is originally based on a separate patch by Ira Weiny, which applied to an early version of the put_user_page() experiments. Since then, Jérôme Glisse suggested the refactoring described above. Cc: Jan Kara <jack@suse.cz> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Suggested-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: John Hubbard <jhubbard@nvidia.com> --- include/linux/mm.h | 27 ++++++++++++++++++++++++--- mm/memremap.c | 16 ++-------------- 2 files changed, 26 insertions(+), 17 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index a2adf95b3f9c..96228376139c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -967,9 +967,10 @@ static inline bool is_zone_device_page(const struct page *page) #endif #ifdef CONFIG_DEV_PAGEMAP_OPS -void __put_devmap_managed_page(struct page *page); +void free_devmap_managed_page(struct page *page); DECLARE_STATIC_KEY_FALSE(devmap_managed_key); -static inline bool put_devmap_managed_page(struct page *page) + +static inline bool page_is_devmap_managed(struct page *page) { if (!static_branch_unlikely(&devmap_managed_key)) return false; @@ -978,7 +979,6 @@ static inline bool put_devmap_managed_page(struct page *page) switch (page->pgmap->type) { case MEMORY_DEVICE_PRIVATE: case MEMORY_DEVICE_FS_DAX: - __put_devmap_managed_page(page); return true; default: break; @@ -986,6 +986,27 @@ static inline bool put_devmap_managed_page(struct page *page) return false; } +static inline bool put_devmap_managed_page(struct page *page) +{ + bool is_devmap = page_is_devmap_managed(page); + + if (is_devmap) { + int 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); + } + + return is_devmap; +} + #else /* CONFIG_DEV_PAGEMAP_OPS */ static inline bool put_devmap_managed_page(struct page *page) { diff --git a/mm/memremap.c b/mm/memremap.c index e899fa876a62..2ba773859031 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -411,20 +411,8 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn, EXPORT_SYMBOL_GPL(get_dev_pagemap); #ifdef CONFIG_DEV_PAGEMAP_OPS -void __put_devmap_managed_page(struct page *page) +void free_devmap_managed_page(struct page *page) { - int count = page_ref_dec_return(page); - - /* still busy */ - if (count > 1) - return; - - /* only triggered by the dev_pagemap shutdown path */ - if (count == 0) { - __put_page(page); - return; - } - /* notify page idle for dax */ if (!is_device_private_page(page)) { wake_up_var(&page->_refcount); @@ -461,5 +449,5 @@ void __put_devmap_managed_page(struct page *page) page->mapping = NULL; page->pgmap->ops->page_free(page); } -EXPORT_SYMBOL(__put_devmap_managed_page); +EXPORT_SYMBOL(free_devmap_managed_page); #endif /* CONFIG_DEV_PAGEMAP_OPS */ -- 2.24.0 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2019-11-15 5:53 UTC|newest] Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-15 5:53 [PATCH v5 00/24] mm/gup: track dma-pinned pages: FOLL_PIN John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 01/24] mm/gup: pass flags arg to __gup_device_* functions John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 02/24] mm/gup: factor out duplicate code from four routines John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-18 9:46 ` Jan Kara 2019-11-18 9:46 ` Jan Kara 2019-11-19 7:00 ` John Hubbard 2019-11-19 7:00 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 03/24] mm/gup: move try_get_compound_head() to top, fix minor issues John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 04/24] mm: Cleanup __put_devmap_managed_page() vs ->page_free() John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` John Hubbard [this message] 2019-11-15 5:53 ` [PATCH v5 05/24] mm: devmap: refactor 1-based refcounting for ZONE_DEVICE pages John Hubbard 2019-11-15 5:53 ` [PATCH v5 06/24] goldish_pipe: rename local pin_user_pages() routine John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-18 9:47 ` Jan Kara 2019-11-18 9:47 ` Jan Kara 2019-11-15 5:53 ` [PATCH v5 07/24] IB/umem: use get_user_pages_fast() to pin DMA pages John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-18 9:49 ` Jan Kara 2019-11-18 9:49 ` Jan Kara 2019-11-15 5:53 ` [PATCH v5 08/24] media/v4l2-core: set pages dirty upon releasing DMA buffers John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 09/24] vfio, mm: fix get_user_pages_remote() and FOLL_LONGTERM John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 14:08 ` Jason Gunthorpe 2019-11-15 18:06 ` Ira Weiny 2019-11-15 18:06 ` Ira Weiny 2019-11-15 5:53 ` [PATCH v5 10/24] mm/gup: introduce pin_user_pages*() and FOLL_PIN John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-18 10:16 ` Jan Kara 2019-11-18 10:16 ` Jan Kara 2019-11-19 5:17 ` John Hubbard 2019-11-19 5:17 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 11/24] goldish_pipe: convert to pin_user_pages() and put_user_page() John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-18 10:16 ` Jan Kara 2019-11-18 10:16 ` Jan Kara 2019-11-15 5:53 ` [PATCH v5 12/24] IB/{core, hw, umem}: set FOLL_PIN via pin_user_pages*(), fix up ODP John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 14:09 ` [PATCH v5 12/24] IB/{core,hw,umem}: " Jason Gunthorpe 2019-11-15 5:53 ` [PATCH v5 13/24] mm/process_vm_access: set FOLL_PIN via pin_user_pages_remote() John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-18 10:30 ` Jan Kara 2019-11-18 10:30 ` Jan Kara 2019-11-15 5:53 ` [PATCH v5 14/24] drm/via: set FOLL_PIN via pin_user_pages_fast() John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 15/24] fs/io_uring: set FOLL_PIN via pin_user_pages() John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-18 10:34 ` Jan Kara 2019-11-18 10:34 ` Jan Kara 2019-11-15 5:53 ` [PATCH v5 16/24] net/xdp: " John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 17/24] mm/gup: track FOLL_PIN pages John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-18 11:58 ` Jan Kara 2019-11-18 11:58 ` Jan Kara 2019-11-19 0:22 ` John Hubbard 2019-11-19 0:22 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 18/24] media/v4l2-core: pin_user_pages (FOLL_PIN) and put_user_page() conversion John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 19/24] vfio, mm: " John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 20/24] powerpc: book3s64: convert to pin_user_pages() and put_user_page() John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 21/24] mm/gup_benchmark: use proper FOLL_WRITE flags instead of hard-coding "1" John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 22/24] mm/gup_benchmark: support pin_user_pages() and related calls John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 23/24] selftests/vm: run_vmtests: invoke gup_benchmark with basic FOLL_PIN coverage John Hubbard 2019-11-15 5:53 ` John Hubbard 2019-11-15 5:53 ` [PATCH v5 24/24] mm, tree-wide: rename put_user_page*() to unpin_user_page*() John Hubbard 2019-11-15 5:53 ` John Hubbard
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20191115055340.1825745-6-jhubbard@nvidia.com \ --to=jhubbard@nvidia.com \ --cc=airlied@linux.ie \ --cc=akpm@linux-foundation.org \ --cc=alex.williamson@redhat.com \ --cc=axboe@kernel.dk \ --cc=benh@kernel.crashing.org \ --cc=bjorn.topel@intel.com \ --cc=corbet@lwn.net \ --cc=dan.j.williams@intel.com \ --cc=daniel@ffwll.ch \ --cc=davem@davemloft.net \ --cc=david@fromorbit.com \ --cc=hch@infradead.org \ --cc=ira.weiny@intel.com \ --cc=jack@suse.cz \ --cc=jgg@ziepe.ca \ --cc=jglisse@redhat.com \ --cc=magnus.karlsson@intel.com \ --cc=mchehab@kernel.org \ --cc=mpe@ellerman.id.au \ --cc=viro@zeniv.linux.org.uk \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).