From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Hildenbrand Date: Wed, 05 Jun 2019 09:00:28 +0000 Subject: Re: [PATCH v3 09/11] mm/memory_hotplug: Remove memory block devices before arch_remove_memory() Message-Id: <38b8b004-9a26-e4ba-d8e3-a41c8fcc51c1@redhat.com> List-Id: References: <20190527111152.16324-1-david@redhat.com> <20190527111152.16324-10-david@redhat.com> <20190604220715.d4d2ctwjk25vd5sq@master> In-Reply-To: <20190604220715.d4d2ctwjk25vd5sq@master> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Wei Yang Cc: Michal Hocko , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Chris Wilson , linux-mm@kvack.org, Arun KS , Ingo Molnar , linux-s390@vger.kernel.org, "Rafael J. Wysocki" , Pavel Tatashin , "mike.travis@hpe.com" , Mark Brown , Jonathan Cameron , Dan Williams , linux-arm-kernel@lists.infradead.org, Oscar Salvador , Andrew Banman , Mathieu Malaterre , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Alex Deucher , Igor Mammedov , akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, "David S. Miller" On 05.06.19 00:07, Wei Yang wrote: > On Mon, May 27, 2019 at 01:11:50PM +0200, David Hildenbrand wrote: >> Let's factor out removing of memory block devices, which is only >> necessary for memory added via add_memory() and friends that created >> memory block devices. Remove the devices before calling >> arch_remove_memory(). >> >> This finishes factoring out memory block device handling from >> arch_add_memory() and arch_remove_memory(). >> >> Cc: Greg Kroah-Hartman >> Cc: "Rafael J. Wysocki" >> Cc: David Hildenbrand >> Cc: "mike.travis@hpe.com" >> Cc: Andrew Morton >> Cc: Andrew Banman >> Cc: Ingo Molnar >> Cc: Alex Deucher >> Cc: "David S. Miller" >> Cc: Mark Brown >> Cc: Chris Wilson >> Cc: Oscar Salvador >> Cc: Jonathan Cameron >> Cc: Michal Hocko >> Cc: Pavel Tatashin >> Cc: Arun KS >> Cc: Mathieu Malaterre >> Reviewed-by: Dan Williams >> Signed-off-by: David Hildenbrand >> --- >> drivers/base/memory.c | 37 ++++++++++++++++++------------------- >> drivers/base/node.c | 11 ++++++----- >> include/linux/memory.h | 2 +- >> include/linux/node.h | 6 ++---- >> mm/memory_hotplug.c | 5 +++-- >> 5 files changed, 30 insertions(+), 31 deletions(-) >> >> diff --git a/drivers/base/memory.c b/drivers/base/memory.c >> index 5a0370f0c506..f28efb0bf5c7 100644 >> --- a/drivers/base/memory.c >> +++ b/drivers/base/memory.c >> @@ -763,32 +763,31 @@ int create_memory_block_devices(unsigned long start, unsigned long size) >> return ret; >> } >> >> -void unregister_memory_section(struct mem_section *section) >> +/* >> + * Remove memory block devices for the given memory area. Start and size >> + * have to be aligned to memory block granularity. Memory block devices >> + * have to be offline. >> + */ >> +void remove_memory_block_devices(unsigned long start, unsigned long size) >> { >> + const int start_block_id = pfn_to_block_id(PFN_DOWN(start)); >> + const int end_block_id = pfn_to_block_id(PFN_DOWN(start + size)); >> struct memory_block *mem; >> + int block_id; >> >> - if (WARN_ON_ONCE(!present_section(section))) >> + if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) || >> + !IS_ALIGNED(size, memory_block_size_bytes()))) >> return; >> >> mutex_lock(&mem_sysfs_mutex); >> - >> - /* >> - * Some users of the memory hotplug do not want/need memblock to >> - * track all sections. Skip over those. >> - */ >> - mem = find_memory_block(section); >> - if (!mem) >> - goto out_unlock; >> - >> - unregister_mem_sect_under_nodes(mem, __section_nr(section)); >> - >> - mem->section_count--; >> - if (mem->section_count = 0) >> + for (block_id = start_block_id; block_id != end_block_id; block_id++) { >> + mem = find_memory_block_by_id(block_id, NULL); >> + if (WARN_ON_ONCE(!mem)) >> + continue; >> + mem->section_count = 0; > > Is this step necessary? It's what the previous code does, it might not be - I'll leave it like that for now. As mentioned in another reply, I might remove the section_count completely, eventually. -- Thanks, David / dhildenb