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[62.201.165.239]) by smtp.gmail.com with ESMTPSA id e14-v6sm9812528wrt.76.2018.10.15.08.30.52 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 15 Oct 2018 08:30:52 -0700 (PDT) Received: from d104.suse.de (charybdis-ext.suse.de [195.135.221.2]) by techadventures.net (Postfix) with ESMTPA id F3C211259A7; Mon, 15 Oct 2018 17:30:51 +0200 (CEST) From: Oscar Salvador To: akpm@linux-foundation.org Cc: mhocko@suse.com, dan.j.williams@intel.com, yasu.isimatu@gmail.com, rppt@linux.vnet.ibm.com, malat@debian.org, linux-kernel@vger.kernel.org, pavel.tatashin@microsoft.com, jglisse@redhat.com, Jonathan.Cameron@huawei.com, rafael@kernel.org, david@redhat.com, dave.jiang@intel.com, linux-mm@kvack.org, alexander.h.duyck@linux.intel.com, Oscar Salvador Subject: [PATCH 2/5] mm/memory_hotplug: Create add/del_device_memory functions Date: Mon, 15 Oct 2018 17:30:31 +0200 Message-Id: <20181015153034.32203-3-osalvador@techadventures.net> X-Mailer: git-send-email 2.13.6 In-Reply-To: <20181015153034.32203-1-osalvador@techadventures.net> References: <20181015153034.32203-1-osalvador@techadventures.net> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oscar Salvador HMM/devm have a particular handling of memory-hotplug. They do not go through the common path, and so, they do not call either offline_pages() or online_pages(). The operations they perform are the following ones: 1) Create the linear mapping in case the memory is not private 2) Initialize the pages and add the sections 3) Move the pages to ZONE_DEVICE Due to this particular handling of hot-add/remove memory from HMM/devm, I think it would be nice to provide a helper function in order to make this cleaner, and not populate other regions with code that should belong to memory-hotplug. The helpers are named: del_device_memory add_device_memory The idea is that add_device_memory will be in charge of: a) call either arch_add_memory() or add_pages(), depending on whether we want a linear mapping b) online the memory sections that correspond to the pfn range c) call move_pfn_range_to_zone() being zone ZONE_DEVICE to expand zone/pgdat spanned pages and initialize its pages del_device_memory, on the other hand, will be in charge of: a) offline the memory sections that correspond to the pfn range b) call shrink_zone_pgdat_pages(), which shrinks node/zone spanned pages. c) call either arch_remove_memory() or __remove_pages(), depending on whether we need to tear down the linear mapping or not The reason behind step b) from add_device_memory() and step a) from del_device_memory is that now find_smallest/biggest_section_pfn will have to check for online sections, and not for valid sections as they used to do, because we call offline_mem_sections() in offline_pages(). In order to split up better the patches and ease the review, this patch will only make a) case work for add_device_memory(), and case c) for del_device_memory. The other cases will be added in the next patch. These two functions have to be called from devm/HMM code: dd_device_memory: - devm_memremap_pages() - hmm_devmem_pages_create() del_device_memory: - hmm_devmem_release - devm_memremap_pages_release One thing I do not know is whether we can move kasan calls out of the hotplug lock or not. If we can, we could move the hotplug lock within add/del_device_memory(). Signed-off-by: Oscar Salvador --- include/linux/memory_hotplug.h | 11 +++++++++++ kernel/memremap.c | 11 ++++------- mm/hmm.c | 33 +++++++++++++++++---------------- mm/memory_hotplug.c | 41 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 73 insertions(+), 23 deletions(-) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 786cdfc9a974..cf014d5edbb2 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -111,8 +111,19 @@ extern int arch_remove_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap); extern int __remove_pages(struct zone *zone, unsigned long start_pfn, unsigned long nr_pages, struct vmem_altmap *altmap); + +#ifdef CONFIG_ZONE_DEVICE +extern int del_device_memory(int nid, unsigned long start, unsigned long size, + struct vmem_altmap *altmap, bool private_mem); +#endif + #endif /* CONFIG_MEMORY_HOTREMOVE */ +#ifdef CONFIG_ZONE_DEVICE +extern int add_device_memory(int nid, unsigned long start, unsigned long size, + struct vmem_altmap *altmap, bool private_mem); +#endif + /* reasonably generic interface to expand the physical pages */ extern int __add_pages(int nid, unsigned long start_pfn, unsigned long nr_pages, struct vmem_altmap *altmap, bool want_memblock); diff --git a/kernel/memremap.c b/kernel/memremap.c index c95df6ed2d4a..b86bba8713b9 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -86,6 +86,8 @@ static void devm_memremap_pages_release(void *data) struct device *dev = pgmap->dev; struct resource *res = &pgmap->res; resource_size_t align_start, align_size; + struct vmem_altmap *altmap = pgmap->altmap_valid ? + &pgmap->altmap : NULL; unsigned long pfn; int nid; @@ -104,8 +106,7 @@ static void devm_memremap_pages_release(void *data) nid = dev_to_node(dev); mem_hotplug_begin(); - arch_remove_memory(nid, align_start, align_size, pgmap->altmap_valid ? - &pgmap->altmap : NULL); + del_device_memory(nid, align_start, align_size, altmap, true); kasan_remove_zero_shadow(__va(align_start), align_size); mem_hotplug_done(); @@ -204,11 +205,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) goto err_kasan; } - error = arch_add_memory(nid, align_start, align_size, altmap, false); - if (!error) - move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], - align_start >> PAGE_SHIFT, - align_size >> PAGE_SHIFT, altmap); + error = add_device_memory(nid, align_start, align_size, altmap, true); mem_hotplug_done(); if (error) goto err_add_memory; diff --git a/mm/hmm.c b/mm/hmm.c index 42d79bcc8aab..d3e52ae71bd9 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -996,6 +996,7 @@ static void hmm_devmem_release(struct device *dev, void *data) struct zone *zone; struct page *page; int nid; + bool mapping; if (percpu_ref_tryget_live(&devmem->ref)) { dev_WARN(dev, "%s: page mapping is still live!\n", __func__); @@ -1010,12 +1011,15 @@ static void hmm_devmem_release(struct device *dev, void *data) zone = page_zone(page); nid = zone->zone_pgdat->node_id; - mem_hotplug_begin(); if (resource->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) - __remove_pages(zone, start_pfn, npages, NULL); + mapping = false; else - arch_remove_memory(nid, start_pfn << PAGE_SHIFT, - npages << PAGE_SHIFT, NULL); + mapping = true; + + mem_hotplug_begin(); + del_device_memory(nid, start_pfn << PAGE_SHIFT, npages << PAGE_SHIFT, + NULL, + mapping); mem_hotplug_done(); hmm_devmem_radix_release(resource); @@ -1026,6 +1030,7 @@ static int hmm_devmem_pages_create(struct hmm_devmem *devmem) resource_size_t key, align_start, align_size, align_end; struct device *device = devmem->device; int ret, nid, is_ram; + bool mapping; align_start = devmem->resource->start & ~(PA_SECTION_SIZE - 1); align_size = ALIGN(devmem->resource->start + @@ -1084,7 +1089,6 @@ static int hmm_devmem_pages_create(struct hmm_devmem *devmem) if (nid < 0) nid = numa_mem_id(); - mem_hotplug_begin(); /* * For device private memory we call add_pages() as we only need to * allocate and initialize struct page for the device memory. More- @@ -1096,20 +1100,17 @@ static int hmm_devmem_pages_create(struct hmm_devmem *devmem) * want the linear mapping and thus use arch_add_memory(). */ if (devmem->pagemap.type == MEMORY_DEVICE_PUBLIC) - ret = arch_add_memory(nid, align_start, align_size, NULL, - false); + mapping = true; else - ret = add_pages(nid, align_start >> PAGE_SHIFT, - align_size >> PAGE_SHIFT, NULL, false); - if (ret) { - mem_hotplug_done(); - goto error_add_memory; - } - move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], - align_start >> PAGE_SHIFT, - align_size >> PAGE_SHIFT, NULL); + mapping = false; + + mem_hotplug_begin(); + ret = add_device_memory(nid, align_start, align_size, NULL, mapping); mem_hotplug_done(); + if (ret) + goto error_add_memory; + /* * Initialization of the pages has been deferred until now in order * to allow us to do the work while not holding the hotplug lock. diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 33d448314b3f..5874aceb81ac 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1889,4 +1889,45 @@ void remove_memory(int nid, u64 start, u64 size) unlock_device_hotplug(); } EXPORT_SYMBOL_GPL(remove_memory); + +#ifdef CONFIG_ZONE_DEVICE +int del_device_memory(int nid, unsigned long start, unsigned long size, + struct vmem_altmap *altmap, bool mapping) +{ + int ret; + unsigned long start_pfn = PHYS_PFN(start); + unsigned long nr_pages = size >> PAGE_SHIFT; + struct zone *zone = page_zone(pfn_to_page(pfn)); + + if (mapping) + ret = arch_remove_memory(nid, start, size, altmap); + else + ret = __remove_pages(zone, start_pfn, nr_pages, altmap); + + return ret; +} +#endif #endif /* CONFIG_MEMORY_HOTREMOVE */ + +#ifdef CONFIG_ZONE_DEVICE +int add_device_memory(int nid, unsigned long start, unsigned long size, + struct vmem_altmap *altmap, bool mapping) +{ + int ret; + unsigned long start_pfn = PHYS_PFN(start); + unsigned long nr_pages = size >> PAGE_SHIFT; + + if (mapping) + ret = arch_add_memory(nid, start, size, altmap, false); + else + ret = add_pages(nid, start_pfn, nr_pages, altmap, false); + + if (!ret) { + struct zone *zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE]; + + move_pfn_range_to_zone(zone, start_pfn, nr_pages, altmap); + } + + return ret; +} +#endif -- 2.13.6