From: Mike Kravetz <mike.kravetz@oracle.com>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org,
linux-s390@vger.kernel.org, sparclinux@vger.kernel.org,
linux-doc@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
"David S.Miller" <davem@davemloft.net>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Jonathan Corbet <corbet@lwn.net>, Longpeng <longpeng2@huawei.com>,
Christophe Leroy <christophe.leroy@c-s.fr>,
Randy Dunlap <rdunlap@infradead.org>,
Mina Almasry <almasrymina@google.com>,
Peter Xu <peterx@redhat.com>,
Nitesh Narayan Lal <nitesh@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v3 3/4] hugetlbfs: remove hugetlb_add_hstate() warning for existing hstate
Date: Wed, 22 Apr 2020 09:56:03 -0700 [thread overview]
Message-ID: <d39a33da-6095-c616-6bff-6af8795922d1@oracle.com> (raw)
In-Reply-To: <87blnj4x9p.fsf@linux.ibm.com>
On 4/22/20 3:42 AM, Aneesh Kumar K.V wrote:
> Mike Kravetz <mike.kravetz@oracle.com> writes:
>
>> The routine hugetlb_add_hstate prints a warning if the hstate already
>> exists. This was originally done as part of kernel command line
>> parsing. If 'hugepagesz=' was specified more than once, the warning
>> pr_warn("hugepagesz= specified twice, ignoring\n");
>> would be printed.
>>
>> Some architectures want to enable all huge page sizes. They would
>> call hugetlb_add_hstate for all supported sizes. However, this was
>> done after command line processing and as a result hstates could have
>> already been created for some sizes. To make sure no warning were
>> printed, there would often be code like:
>> if (!size_to_hstate(size)
>> hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT)
>>
>> The only time we want to print the warning is as the result of command
>> line processing.
>
> Does this patch break hugepages=x command line? I haven't tested this
> yet. But one of the details w.r.t. skipping that hugetlb_add_hstate is
> to make sure we can configure the max_huge_pages.
>
Are you asking about hugepages=x being the only option on the command line?
If so, then the behavior is not changed. This will result in x pages of
default huge page size being allocated. Where default huge page size is of
course architecture dependent. On an x86 VM,
[ 0.040474] Kernel command line: BOOT_IMAGE=/vmlinuz-5.6.0-mm1+ root=/dev/mapper/fedora_new--host-root ro rd.lvm.lv=fedora_new-host/root rd.lvm.lv=fedora_new-host/swap console=tty0 console=ttyS0,115200 audit=0 transparent_hugepage=always hugepages=128
[ 0.332618] HugeTLB registered 1.00 GiB page size, pre-allocated 0 pages
[ 0.333245] HugeTLB registered 2.00 MiB page size, pre-allocated 128 pages
BTW - Here are the command line options I tested on x86 with this series.
No errors or warnings
---------------------
hugepages=128
hugepagesz=2M hugepages=128
default_hugepagesz=2M hugepages=128
hugepages=128 default_hugepagesz=2M
hugepagesz=1G hugepages=2
hugepages=2 default_hugepagesz=1G
default_hugepagesz=1G hugepages=2
hugepages=128 hugepagesz=1G hugepages=2
hugepagesz=1G hugepages=2 hugepagesz=2M hugepages=128
default_hugepagesz=2M hugepages=128 hugepagesz=1G hugepages=2
hugepages=128 default_hugepagesz=2M hugepagesz=1G hugepages=2
hugepages=2 default_hugepagesz=1G hugepagesz=2M hugepages=128
default_hugepagesz=1G hugepages=2 hugepagesz=2M hugepages=128
default_hugepagesz=2M hugepagesz=2M hugepages=128
default_hugepagesz=2M hugepagesz=1G hugepages=2 hugepagesz=2M hugepages=128
Error or warning
----------------
hugepages=128 hugepagesz=2M hugepages=256
hugepagesz=2M hugepages=128 hugepagesz=2M hugepages=256
default_hugepagesz=2M hugepages=128 hugepagesz=2M hugepages=256
hugepages=128 hugepages=256
hugepagesz=2M hugepages=128 hugepages=2 default_hugepagesz=1G
--
Mike Kravetz
next prev parent reply other threads:[~2020-04-22 16:57 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-17 18:50 [PATCH v3 0/4] Clean up hugetlb boot command line processing Mike Kravetz
2020-04-17 18:50 ` [PATCH v3 1/4] hugetlbfs: add arch_hugetlb_valid_size Mike Kravetz
2020-04-17 18:50 ` [PATCH v3 2/4] hugetlbfs: move hugepagesz= parsing to arch independent code Mike Kravetz
2020-04-27 5:04 ` Sandipan Das
2020-04-27 17:25 ` Mike Kravetz
2020-04-27 19:09 ` Mike Kravetz
2020-04-27 20:18 ` Andrew Morton
2020-04-27 20:31 ` Mike Kravetz
2020-04-28 4:17 ` Sandipan Das
2020-04-17 18:50 ` [PATCH v3 3/4] hugetlbfs: remove hugetlb_add_hstate() warning for existing hstate Mike Kravetz
2020-04-20 19:41 ` Anders Roxell
2020-04-22 10:42 ` Aneesh Kumar K.V
2020-04-22 16:56 ` Mike Kravetz [this message]
2020-04-17 18:50 ` [PATCH v3 4/4] hugetlbfs: clean up command line processing Mike Kravetz
2020-04-20 15:34 ` [PATCH v3 0/4] Clean up hugetlb boot " Qian Cai
2020-04-20 18:20 ` Mike Kravetz
2020-04-20 19:45 ` Will Deacon
2020-04-20 20:29 ` Anders Roxell
2020-04-20 21:40 ` Mike Kravetz
2020-04-20 22:53 ` Anders Roxell
2020-04-21 6:58 ` Will Deacon
2020-04-21 14:02 ` Gerald Schaefer
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