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[2003:cb:c70a:ed00:7ddf:1ea9:4f7a:91fe]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4327d698055sm25127635e9.40.2024.10.31.05.37.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 31 Oct 2024 05:37:14 -0700 (PDT) Message-ID: <2c507326-3267-431e-936a-23e2ab6a3baf@redhat.com> Date: Thu, 31 Oct 2024 13:37:13 +0100 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 3/4] mm: shmem: override mTHP shmem default with a kernel parameter To: =?UTF-8?Q?Ma=C3=ADra_Canal?= , Jonathan Corbet , Andrew Morton , Hugh Dickins , Barry Song , Ryan Roberts , Baolin Wang , Lance Yang Cc: linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-dev@igalia.com References: <20241030130308.1066299-1-mcanal@igalia.com> <20241030130308.1066299-4-mcanal@igalia.com> From: David Hildenbrand Content-Language: en-US Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <20241030130308.1066299-4-mcanal@igalia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 30.10.24 13:58, Maíra Canal wrote: > Add the ``thp_shmem=`` kernel command line to allow specifying the > default policy of each supported shmem hugepage size. The kernel parameter > accepts the following format: > > thp_shmem=[KMG],[KMG]:;[KMG]-[KMG]: > > For example, > > thp_shmem=16K-64K:always;128K,512K:inherit;256K:advise;1M-2M:never;4M-8M:within_size > > By configuring the default policy of several shmem hugepages, the user > can take advantage of mTHP before it's been configured through sysfs. > > Signed-off-by: Maíra Canal > --- > .../admin-guide/kernel-parameters.txt | 10 ++ > Documentation/admin-guide/mm/transhuge.rst | 17 +++ > mm/shmem.c | 109 +++++++++++++++++- > 3 files changed, 135 insertions(+), 1 deletion(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index acabb04d0dd4..b48d744d99b0 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -6700,6 +6700,16 @@ > Force threading of all interrupt handlers except those > marked explicitly IRQF_NO_THREAD. > > + thp_shmem= [KNL] > + Format: [KMG],[KMG]:;[KMG]-[KMG]: > + Control the default policy of each hugepage size for the > + internal shmem mount. is one of policies available > + for the shmem mount ("always", "inherit", "never", "within_size", > + and "advise"). > + It can be used multiple times for multiple shmem THP sizes. > + See Documentation/admin-guide/mm/transhuge.rst for more > + details. > + > topology= [S390,EARLY] > Format: {off | on} > Specify if the kernel should make use of the cpu > diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst > index 9b5b02c4d1ab..47e7fc30e22d 100644 > --- a/Documentation/admin-guide/mm/transhuge.rst > +++ b/Documentation/admin-guide/mm/transhuge.rst > @@ -332,6 +332,23 @@ allocation policy for the internal shmem mount by using the kernel parameter > seven valid policies for shmem (``always``, ``within_size``, ``advise``, > ``never``, ``deny``, and ``force``). > > +In the same manner as ``thp_anon`` controls each supported anonymous THP > +size, ``thp_shmem`` controls each supported shmem THP size. ``thp_shmem`` > +has the same format as ``thp_anon``, but also supports the policy > +``within_size``. > + > +``thp_shmem=`` may be specified multiple times to configure all THP sizes > +as required. If ``thp_shmem=`` is specified at least once, any shmem THP > +sizes not explicitly configured on the command line are implicitly set to > +``never``. > + > +``transparent_hugepage_shmem`` setting only affects the global toggle. If > +``thp_shmem`` is not specified, PMD_ORDER hugepage will default to > +``inherit``. However, if a valid ``thp_shmem`` setting is provided by the > +user, the PMD_ORDER hugepage policy will be overridden. If the policy for > +PMD_ORDER is not defined within a valid ``thp_shmem``, its policy will > +default to ``never``. > + > Hugepages in tmpfs/shmem > ======================== > > diff --git a/mm/shmem.c b/mm/shmem.c > index dfcc88ec6e34..c2299fa0b345 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -136,6 +136,7 @@ static unsigned long huge_shmem_orders_always __read_mostly; > static unsigned long huge_shmem_orders_madvise __read_mostly; > static unsigned long huge_shmem_orders_inherit __read_mostly; > static unsigned long huge_shmem_orders_within_size __read_mostly; > +static bool shmem_orders_configured __initdata; > #endif > > #ifdef CONFIG_TMPFS > @@ -5027,7 +5028,8 @@ void __init shmem_init(void) > * Default to setting PMD-sized THP to inherit the global setting and > * disable all other multi-size THPs. > */ > - huge_shmem_orders_inherit = BIT(HPAGE_PMD_ORDER); > + if (!shmem_orders_configured) > + huge_shmem_orders_inherit = BIT(HPAGE_PMD_ORDER); > #endif > return; > > @@ -5180,6 +5182,26 @@ struct kobj_attribute thpsize_shmem_enabled_attr = > > #if defined(CONFIG_TRANSPARENT_HUGEPAGE) > > +static inline int get_order_from_str(const char *size_str) > +{ > + unsigned long size; > + char *endptr; > + int order; > + > + size = memparse(size_str, &endptr); > + > + if (!is_power_of_2(size)) > + goto err; > + order = get_order(size); > + if (BIT(order) & ~THP_ORDERS_ALL_FILE_DEFAULT) > + goto err; > + > + return order; > +err: > + pr_err("invalid size %s in thp_shmem boot parameter\n", size_str); > + return -EINVAL; > +} Hm, mostly copy and paste. You could reuse existing get_order_from_str() simply by passing in the supported orders and moving error reporting to the caller. static inline int get_order_from_str(const char *size_str, int valid_orders) { ... if (!is_power_of_2(size)) return -EINVAL; order = get_order(size); if (BIT(order) & ~valid_orders) return -EINVAL; return order; } > + > static int __init setup_transparent_hugepage_shmem(char *str) > { > int huge; > @@ -5195,6 +5217,91 @@ static int __init setup_transparent_hugepage_shmem(char *str) > } > __setup("transparent_hugepage_shmem=", setup_transparent_hugepage_shmem); > > +static char str_dup[PAGE_SIZE] __initdata; > +static int __init setup_thp_shmem(char *str) > +{ > + char *token, *range, *policy, *subtoken; > + unsigned long always, inherit, madvise, within_size; > + char *start_size, *end_size; > + int start, end, nr; > + char *p; > + > + if (!str || strlen(str) + 1 > PAGE_SIZE) > + goto err; > + strscpy(str_dup, str); > + > + always = huge_shmem_orders_always; > + inherit = huge_shmem_orders_inherit; > + madvise = huge_shmem_orders_madvise; > + within_size = huge_shmem_orders_within_size; > + p = str_dup; > + while ((token = strsep(&p, ";")) != NULL) { > + range = strsep(&token, ":"); > + policy = token; > + > + if (!policy) > + goto err; > + > + while ((subtoken = strsep(&range, ",")) != NULL) { > + if (strchr(subtoken, '-')) { > + start_size = strsep(&subtoken, "-"); > + end_size = subtoken; > + > + start = get_order_from_str(start_size); > + end = get_order_from_str(end_size); > + } else { > + start = end = get_order_from_str(subtoken); > + } > + > + if (start < 0 || end < 0 || start > end) > + goto err; > + > + nr = end - start + 1; > + if (!strcmp(policy, "always")) { > + bitmap_set(&always, start, nr); > + bitmap_clear(&inherit, start, nr); > + bitmap_clear(&madvise, start, nr); > + bitmap_clear(&within_size, start, nr); > + } else if (!strcmp(policy, "advise")) { > + bitmap_set(&madvise, start, nr); > + bitmap_clear(&inherit, start, nr); > + bitmap_clear(&always, start, nr); > + bitmap_clear(&within_size, start, nr); > + } else if (!strcmp(policy, "inherit")) { > + bitmap_set(&inherit, start, nr); > + bitmap_clear(&madvise, start, nr); > + bitmap_clear(&always, start, nr); > + bitmap_clear(&within_size, start, nr); > + } else if (!strcmp(policy, "within_size")) { > + bitmap_set(&within_size, start, nr); > + bitmap_clear(&inherit, start, nr); > + bitmap_clear(&madvise, start, nr); > + bitmap_clear(&always, start, nr); > + } else if (!strcmp(policy, "never")) { > + bitmap_clear(&inherit, start, nr); > + bitmap_clear(&madvise, start, nr); > + bitmap_clear(&always, start, nr); > + bitmap_clear(&within_size, start, nr); > + } else { > + pr_err("invalid policy %s in thp_shmem boot parameter\n", policy); > + goto err; > + } > + } > + } Similarly, copy-paste. But not that easy to abstract :) So maybe we'll have to keep that as is for now. -- Cheers, David / dhildenb