From: Muchun Song <songmuchun@bytedance.com>
To: Oscar Salvador <osalvador@suse.de>
Cc: "Jonathan Corbet" <corbet@lwn.net>,
"Mike Kravetz" <mike.kravetz@oracle.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
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hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org,
"Peter Zijlstra" <peterz@infradead.org>,
"Alexander Viro" <viro@zeniv.linux.org.uk>,
"Andrew Morton" <akpm@linux-foundation.org>,
paulmck@kernel.org, pawan.kumar.gupta@linux.intel.com,
"Randy Dunlap" <rdunlap@infradead.org>,
oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de,
"Mina Almasry" <almasrymina@google.com>,
"David Rientjes" <rientjes@google.com>,
"Matthew Wilcox" <willy@infradead.org>,
"Michal Hocko" <mhocko@suse.com>,
"Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com>,
"David Hildenbrand" <david@redhat.com>,
"HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.com>,
"Joao Martins" <joao.m.martins@oracle.com>,
"Xiongchun duan" <duanxiongchun@bytedance.com>,
fam.zheng@bytedance.com, linux-doc@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
"Linux Memory Management List" <linux-mm@kvack.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [External] Re: [PATCH v20 8/9] mm: memory_hotplug: disable memmap_on_memory when hugetlb_free_vmemmap enabled
Date: Wed, 21 Apr 2021 11:41:24 +0800 [thread overview]
Message-ID: <CAMZfGtXmDhkCWateAR0q_EgRPDmGh_=D-6UuhMd+Si6=TDvghQ@mail.gmail.com> (raw)
In-Reply-To: <YH6udU5rKmDcx5dY@localhost.localdomain>
On Tue, Apr 20, 2021 at 6:35 PM Oscar Salvador <osalvador@suse.de> wrote:
>
> On Thu, Apr 15, 2021 at 04:40:04PM +0800, Muchun Song wrote:
> > bool mhp_supports_memmap_on_memory(unsigned long size)
> > {
> > + bool supported;
> > unsigned long nr_vmemmap_pages = size / PAGE_SIZE;
> > unsigned long vmemmap_size = nr_vmemmap_pages * sizeof(struct page);
> > unsigned long remaining_size = size - vmemmap_size;
> > @@ -1011,11 +1012,18 @@ bool mhp_supports_memmap_on_memory(unsigned long size)
> > * altmap as an alternative source of memory, and we do not exactly
> > * populate a single PMD.
> > */
> > - return memmap_on_memory &&
> > - IS_ENABLED(CONFIG_MHP_MEMMAP_ON_MEMORY) &&
> > - size == memory_block_size_bytes() &&
> > - IS_ALIGNED(vmemmap_size, PMD_SIZE) &&
> > - IS_ALIGNED(remaining_size, pageblock_nr_pages << PAGE_SHIFT);
> > + supported = memmap_on_memory &&
> > + IS_ENABLED(CONFIG_MHP_MEMMAP_ON_MEMORY) &&
> > + size == memory_block_size_bytes() &&
> > + IS_ALIGNED(vmemmap_size, PMD_SIZE) &&
> > + IS_ALIGNED(remaining_size, pageblock_nr_pages << PAGE_SHIFT);
> > +
> > + if (supported && is_hugetlb_free_vmemmap_enabled()) {
> > + pr_info("Cannot enable memory_hotplug.memmap_on_memory, it is not compatible with hugetlb_free_vmemmap\n");
> > + supported = false;
> > + }
>
> I would not print anything and rather have
>
> return memmap_on_memory &&
> !is_hugetlb_free_vmemmap_enabled &&
> IS_ENABLED(CONFIG_MHP_MEMMAP_ON_MEMORY) &&
> size == memory_block_size_bytes() &&
> IS_ALIGNED(vmemmap_size, PMD_SIZE) &&
> IS_ALIGNED(remaining_size, pageblock_nr_pages << PAGE_SHIFT);
OK. Will do.
>
> Documentation/admin-guide/kernel-parameters.txt already provides an
> explanation on memory_hotplug.memmap_on_memory parameter that states
> that the feature cannot be enabled when using hugetlb-vmemmap
> optimization.
>
> Users can always check whether the feature is enabled via
> /sys/modules/memory_hotplug/parameters/memmap_on_memory.
If memory_hotplug.memmap_on_memory is enabled
$ cat /sys/module/memory_hotplug/parameters/memmap_on_memory
$ Y
If memory_hotplug.memmap_on_memory is disabled
$ cat /sys/module/memory_hotplug/parameters/memmap_on_memory
$ N
>
> Also, I did not check if it is, but if not, the fact about hugetlb-vmemmmap vs
> hotplug-vmemmap should also be called out in the hugetlb-vmemmap kernel
> parameter.
Make sense. I will update the doc.
Thanks.
>
> Thanks
>
> --
> Oscar Salvador
> SUSE L3
next prev parent reply other threads:[~2021-04-21 3:42 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-15 8:39 [PATCH v20 0/9] Free some vmemmap pages of HugeTLB page Muchun Song
2021-04-15 8:39 ` [PATCH v20 1/9] mm: memory_hotplug: factor out bootmem core functions to bootmem_info.c Muchun Song
2021-04-15 8:39 ` [PATCH v20 2/9] mm: hugetlb: introduce a new config HUGETLB_PAGE_FREE_VMEMMAP Muchun Song
2021-04-15 8:39 ` [PATCH v20 3/9] mm: hugetlb: gather discrete indexes of tail page Muchun Song
2021-04-16 18:54 ` Mike Kravetz
2021-04-15 8:40 ` [PATCH v20 4/9] mm: hugetlb: free the vmemmap pages associated with each HugeTLB page Muchun Song
2021-04-16 21:10 ` Mike Kravetz
2021-04-17 2:55 ` [External] " Muchun Song
2021-04-15 8:40 ` [PATCH v20 5/9] mm: hugetlb: defer freeing of HugeTLB pages Muchun Song
2021-04-16 23:55 ` Mike Kravetz
2021-04-17 4:13 ` [External] " Muchun Song
2021-04-15 8:40 ` [PATCH v20 6/9] mm: hugetlb: alloc the vmemmap pages associated with each HugeTLB page Muchun Song
2021-04-19 23:19 ` Mike Kravetz
2021-04-20 8:46 ` [External] " Muchun Song
2021-04-20 17:48 ` Mike Kravetz
2021-04-21 3:42 ` Muchun Song
2021-04-15 8:40 ` [PATCH v20 7/9] mm: hugetlb: add a kernel parameter hugetlb_free_vmemmap Muchun Song
2021-04-19 23:41 ` Mike Kravetz
2021-04-15 8:40 ` [PATCH v20 8/9] mm: memory_hotplug: disable memmap_on_memory when hugetlb_free_vmemmap enabled Muchun Song
2021-04-20 10:35 ` Oscar Salvador
2021-04-21 3:41 ` Muchun Song [this message]
2021-04-21 7:33 ` [External] " Oscar Salvador
2021-04-21 9:06 ` Muchun Song
2021-04-15 8:40 ` [PATCH v20 9/9] mm: hugetlb: introduce nr_free_vmemmap_pages in the struct hstate Muchun Song
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