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Thu, 9 May 2019 23:55:42 +1000 (AEST) Received: by mail-ed1-x541.google.com with SMTP id w11so2117393edl.5 for ; Thu, 09 May 2019 06:55:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-disposition:in-reply-to:user-agent; bh=rj8sR0p1Edqa94H02tBjaXnEUtoaRjwEJVzZPumNj1g=; b=oQCvYs9jZqA0mKZRzCMWu05oFj2Zz17/PVNd4bwpPPpxmMr0K+ZQCs7yxqlPtfjuMy 8OjUA2czA5H6SB9uPKPi/jS92gskpNjvYeYP/Q4yo9+o9Xrd9/e5lEK5NKwBomh3Cy8d txu9rR8KNjutQFiKex2oKNITF45PZElb82I9QA/6KUxfMCLsrY1lDcu5LtawuUioBTcj C363GL59Zdaxz2o8wF08BTrzO41fdEKqPgs6o4QzXc1PYVqQv9UpbOEWVkNzzqcmKdVj 852r0xVwgC3ApDh6OJFtIWvfw2X6OVJBAUv3KUKUNUdncpeZkAmD/cq2XxXLjQEZfw5F hPxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:reply-to :references:mime-version:content-disposition:in-reply-to:user-agent; bh=rj8sR0p1Edqa94H02tBjaXnEUtoaRjwEJVzZPumNj1g=; 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charset=us-ascii Content-Disposition: inline In-Reply-To: <20190507183804.5512-5-david@redhat.com> User-Agent: NeoMutt/20170113 (1.7.2) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Wei Yang Cc: linux-s390@vger.kernel.org, Michal Hocko , linux-ia64@vger.kernel.org, Pavel Tatashin , linux-sh@vger.kernel.org, "mike.travis@hpe.com" , Greg Kroah-Hartman , "Rafael J. Wysocki" , Mathieu Malaterre , linux-kernel@vger.kernel.org, Ingo Molnar , linux-mm@kvack.org, Andrew Banman , Qian Cai , Arun KS , akpm@linux-foundation.org, Wei Yang , linuxppc-dev@lists.ozlabs.org, Dan Williams , Oscar Salvador Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, May 07, 2019 at 08:38:00PM +0200, David Hildenbrand wrote: >Only memory to be added to the buddy and to be onlined/offlined by >user space using memory block devices needs (and should have!) memory >block devices. > >Factor out creation of memory block devices Create all devices after >arch_add_memory() succeeded. We can later drop the want_memblock parameter, >because it is now effectively stale. > >Only after memory block devices have been added, memory can be onlined >by user space. This implies, that memory is not visible to user space at >all before arch_add_memory() succeeded. > >Cc: Greg Kroah-Hartman >Cc: "Rafael J. Wysocki" >Cc: David Hildenbrand >Cc: "mike.travis@hpe.com" >Cc: Andrew Morton >Cc: Ingo Molnar >Cc: Andrew Banman >Cc: Oscar Salvador >Cc: Michal Hocko >Cc: Pavel Tatashin >Cc: Qian Cai >Cc: Wei Yang >Cc: Arun KS >Cc: Mathieu Malaterre >Signed-off-by: David Hildenbrand >--- > drivers/base/memory.c | 70 ++++++++++++++++++++++++++---------------- > include/linux/memory.h | 2 +- > mm/memory_hotplug.c | 15 ++++----- > 3 files changed, 53 insertions(+), 34 deletions(-) > >diff --git a/drivers/base/memory.c b/drivers/base/memory.c >index 6e0cb4fda179..862c202a18ca 100644 >--- a/drivers/base/memory.c >+++ b/drivers/base/memory.c >@@ -701,44 +701,62 @@ static int add_memory_block(int base_section_nr) > return 0; > } > >+static void unregister_memory(struct memory_block *memory) >+{ >+ BUG_ON(memory->dev.bus != &memory_subsys); >+ >+ /* drop the ref. we got via find_memory_block() */ >+ put_device(&memory->dev); >+ device_unregister(&memory->dev); >+} >+ > /* >- * need an interface for the VM to add new memory regions, >- * but without onlining it. >+ * Create memory block devices for the given memory area. Start and size >+ * have to be aligned to memory block granularity. Memory block devices >+ * will be initialized as offline. > */ >-int hotplug_memory_register(int nid, struct mem_section *section) >+int hotplug_memory_register(unsigned long start, unsigned long size) > { >- int ret = 0; >+ unsigned long block_nr_pages = memory_block_size_bytes() >> PAGE_SHIFT; >+ unsigned long start_pfn = PFN_DOWN(start); >+ unsigned long end_pfn = start_pfn + (size >> PAGE_SHIFT); >+ unsigned long pfn; > struct memory_block *mem; >+ int ret = 0; > >- mutex_lock(&mem_sysfs_mutex); >+ BUG_ON(!IS_ALIGNED(start, memory_block_size_bytes())); >+ BUG_ON(!IS_ALIGNED(size, memory_block_size_bytes())); > >- mem = find_memory_block(section); >- if (mem) { >- mem->section_count++; >- put_device(&mem->dev); >- } else { >- ret = init_memory_block(&mem, section, MEM_OFFLINE); >+ mutex_lock(&mem_sysfs_mutex); >+ for (pfn = start_pfn; pfn != end_pfn; pfn += block_nr_pages) { >+ mem = find_memory_block(__pfn_to_section(pfn)); >+ if (mem) { >+ WARN_ON_ONCE(false); One question here, the purpose of WARN_ON_ONCE(false) is? Would we trigger this? >+ put_device(&mem->dev); >+ continue; >+ } >+ ret = init_memory_block(&mem, __pfn_to_section(pfn), >+ MEM_OFFLINE); > if (ret) >- goto out; >- mem->section_count++; >+ break; >+ mem->section_count = memory_block_size_bytes() / >+ MIN_MEMORY_BLOCK_SIZE; Maybe we can leverage sections_per_block variable. mem->section_count = sections_per_block; >+ } >+ if (ret) { >+ end_pfn = pfn; >+ for (pfn = start_pfn; pfn != end_pfn; pfn += block_nr_pages) { >+ mem = find_memory_block(__pfn_to_section(pfn)); >+ if (!mem) >+ continue; >+ mem->section_count = 0; >+ unregister_memory(mem); >+ } > } -- Wei Yang Help you, Help me