From: Oscar Salvador <osalvador@suse.de>
To: David Hildenbrand <david@redhat.com>
Cc: Muchun Song <songmuchun@bytedance.com>,
corbet@lwn.net, mike.kravetz@oracle.com, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com,
dave.hansen@linux.intel.com, luto@kernel.org,
peterz@infradead.org, viro@zeniv.linux.org.uk,
akpm@linux-foundation.org, paulmck@kernel.org,
mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com,
rdunlap@infradead.org, oneukum@suse.com,
anshuman.khandual@arm.com, jroedel@suse.de,
almasrymina@google.com, rientjes@google.com, willy@infradead.org,
mhocko@suse.com, song.bao.hua@hisilicon.com,
naoya.horiguchi@nec.com, duanxiongchun@bytedance.com,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v13 09/12] mm: hugetlb: add a kernel parameter hugetlb_free_vmemmap
Date: Mon, 25 Jan 2021 13:08:32 +0100 [thread overview]
Message-ID: <20210125120827.GA29289@linux> (raw)
In-Reply-To: <7550ebba-fdb5-0dc9-a517-dda56bd105d9@redhat.com>
On Mon, Jan 25, 2021 at 12:43:23PM +0100, David Hildenbrand wrote:
> > - if (end - start < PAGES_PER_SECTION * sizeof(struct page))
> > + if (is_hugetlb_free_vmemmap_enabled() ||
> > + end - start < PAGES_PER_SECTION * sizeof(struct page))
>
> This looks irresponsible. You ignore any altmap, even though current
> altmap users (ZONE_DEVICE) will not actually result in applicable
> vmemmaps that huge pages could ever use.
>
> Why do you ignore the altmap completely? This has to be properly
> documented, but IMHO it's not even the right approach to mess with
> altmap here.
The goal was not to ignore altmap but to disable PMD mapping sections
when the feature was enabled.
Shame on me I did not notice that with this, altmap will be ignored.
Something like below maybe:
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
struct vmem_altmap *altmap)
{
int err;
bool populate_base_pages = false;
if ((end - start < PAGES_PER_SECTION * sizeof(struct page)) ||
(is_hugetlb_free_vmemmap_enabled() && !altmap))
populate_base_pages = true;
if (populate_base_pages) {
err = vmemmap_populate_basepages(start, end, node, NULL);
} else if (boot_cpu_has(X86_FEATURE_PSE)) {
....
>
> --
> Thanks,
>
> David / dhildenb
>
>
--
Oscar Salvador
SUSE L3
next prev parent reply other threads:[~2021-01-25 12:08 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-17 15:10 [PATCH v13 00/12] Free some vmemmap pages of HugeTLB page Muchun Song
2021-01-17 15:10 ` [PATCH v13 01/12] mm: memory_hotplug: factor out bootmem core functions to bootmem_info.c Muchun Song
2021-01-25 2:48 ` Miaohe Lin
2021-01-17 15:10 ` [PATCH v13 02/12] mm: hugetlb: introduce a new config HUGETLB_PAGE_FREE_VMEMMAP Muchun Song
2021-01-24 23:58 ` David Rientjes
2021-01-25 3:16 ` Randy Dunlap
2021-01-25 4:06 ` [External] " Muchun Song
2021-01-25 4:08 ` Randy Dunlap
2021-01-25 5:06 ` Muchun Song
2021-01-25 18:47 ` David Rientjes
2021-01-26 2:45 ` Muchun Song
2021-01-26 20:13 ` David Rientjes
2021-01-26 2:07 ` Miaohe Lin
2021-01-17 15:10 ` [PATCH v13 03/12] mm: hugetlb: free the vmemmap pages associated with each HugeTLB page Muchun Song
2021-01-17 15:29 ` Muchun Song
2021-01-23 0:59 ` Mike Kravetz
2021-01-23 3:22 ` [External] " Muchun Song
2021-01-23 17:52 ` Oscar Salvador
2021-01-24 6:48 ` [External] " Muchun Song
2021-01-17 15:10 ` [PATCH v13 04/12] mm: hugetlb: defer freeing of HugeTLB pages Muchun Song
2021-01-24 23:55 ` David Rientjes
2021-01-25 3:58 ` [External] " Muchun Song
2021-01-17 15:10 ` [PATCH v13 05/12] mm: hugetlb: allocate the vmemmap pages associated with each HugeTLB page Muchun Song
2021-01-25 0:05 ` David Rientjes
2021-01-25 6:40 ` [External] " Muchun Song
2021-01-25 7:41 ` Muchun Song
2021-01-25 9:15 ` David Hildenbrand
2021-01-25 9:34 ` Muchun Song
2021-01-25 23:25 ` Mike Kravetz
2021-01-26 7:48 ` Oscar Salvador
2021-01-26 9:29 ` Oscar Salvador
2021-01-26 9:36 ` David Hildenbrand
2021-01-26 14:58 ` Oscar Salvador
2021-01-26 15:10 ` David Hildenbrand
2021-01-26 15:34 ` Oscar Salvador
2021-01-26 15:56 ` David Hildenbrand
2021-01-27 10:36 ` David Hildenbrand
2021-01-28 12:37 ` [External] " Muchun Song
2021-01-28 13:08 ` Muchun Song
2021-01-29 1:04 ` Mike Kravetz
2021-01-29 6:56 ` Muchun Song
2021-02-01 16:10 ` David Hildenbrand
2021-02-02 0:05 ` Mike Kravetz
2021-01-28 22:29 ` Oscar Salvador
2021-01-29 6:16 ` [External] " Muchun Song
2021-02-01 15:50 ` David Hildenbrand
2021-01-17 15:10 ` [PATCH v13 06/12] mm: hugetlb: set the PageHWPoison to the raw error page Muchun Song
2021-01-25 0:06 ` David Rientjes
2021-01-25 5:06 ` [External] " Muchun Song
2021-01-17 15:10 ` [PATCH v13 07/12] mm: hugetlb: flush work when dissolving a HugeTLB page Muchun Song
2021-01-17 15:10 ` [PATCH v13 08/12] mm: hugetlb: introduce PageHugeInflight Muchun Song
2021-01-17 15:10 ` [PATCH v13 09/12] mm: hugetlb: add a kernel parameter hugetlb_free_vmemmap Muchun Song
2021-01-25 11:43 ` David Hildenbrand
2021-01-25 12:08 ` Oscar Salvador [this message]
2021-01-25 12:31 ` [External] " Muchun Song
2021-01-25 12:30 ` Muchun Song
2021-01-17 15:10 ` [PATCH v13 10/12] mm: hugetlb: introduce nr_free_vmemmap_pages in the struct hstate Muchun Song
2021-01-17 15:10 ` [PATCH v13 11/12] mm: hugetlb: gather discrete indexes of tail page Muchun Song
2021-01-17 15:10 ` [PATCH v13 12/12] mm: hugetlb: optimize the code with the help of the compiler Muchun Song
2021-01-20 12:52 ` [PATCH v13 00/12] Free some vmemmap pages of HugeTLB page Muchun Song
2021-01-20 13:10 ` Oscar Salvador
2021-01-20 14:22 ` [External] " Muchun Song
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