From: Oscar Salvador <osalvador@suse.de>
To: Muchun Song <songmuchun@bytedance.com>
Cc: 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,
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, david@redhat.com,
naoya.horiguchi@nec.com, joao.m.martins@oracle.com,
duanxiongchun@bytedance.com, fam.zheng@bytedance.com,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v20 8/9] mm: memory_hotplug: disable memmap_on_memory when hugetlb_free_vmemmap enabled
Date: Tue, 20 Apr 2021 12:35:33 +0200 [thread overview]
Message-ID: <YH6udU5rKmDcx5dY@localhost.localdomain> (raw)
In-Reply-To: <20210415084005.25049-9-songmuchun@bytedance.com>
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);
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.
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.
Thanks
--
Oscar Salvador
SUSE L3
next prev parent reply other threads:[~2021-04-20 10:35 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 [this message]
2021-04-21 3:41 ` [External] " Muchun Song
2021-04-21 7:33 ` 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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YH6udU5rKmDcx5dY@localhost.localdomain \
--to=osalvador@suse.de \
--cc=akpm@linux-foundation.org \
--cc=almasrymina@google.com \
--cc=anshuman.khandual@arm.com \
--cc=bp@alien8.de \
--cc=corbet@lwn.net \
--cc=dave.hansen@linux.intel.com \
--cc=david@redhat.com \
--cc=duanxiongchun@bytedance.com \
--cc=fam.zheng@bytedance.com \
--cc=hpa@zytor.com \
--cc=joao.m.martins@oracle.com \
--cc=jroedel@suse.de \
--cc=linux-doc@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=mhocko@suse.com \
--cc=mike.kravetz@oracle.com \
--cc=mingo@redhat.com \
--cc=naoya.horiguchi@nec.com \
--cc=oneukum@suse.com \
--cc=paulmck@kernel.org \
--cc=pawan.kumar.gupta@linux.intel.com \
--cc=peterz@infradead.org \
--cc=rdunlap@infradead.org \
--cc=rientjes@google.com \
--cc=song.bao.hua@hisilicon.com \
--cc=songmuchun@bytedance.com \
--cc=tglx@linutronix.de \
--cc=viro@zeniv.linux.org.uk \
--cc=willy@infradead.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).