From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 152821EBFEB for ; Wed, 4 Sep 2024 10:18:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725445129; cv=none; b=Qp64aLf2tAIDLtk8N7n3x1Uqvovkq7a/9gBasSc4RwJRMZdHcM1M3lsBlM4TAIhACs6Coh/HYiU9c2P0vmtd0G+w8Dt6RxBzm633bBEwYbc+5S6O5Np5sIU1OiTakXCAzMa06p2DbLC1d2UediVPoi2j2D4wqq92G5Kc8goKSEU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725445129; c=relaxed/simple; bh=X9luuGaOYVhD/0UEqNofrFLgoGL4FNEdet6VMrvhIuA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=FoOvmPMWTVkJXopHjoQCZpUyohRroefFwFKOOBjHF6/9Q4BifGEnK8npRLXqEXqX4TGmp6wLwlrtAdKZDbtYrK9kl2ksJMo09+qUkccM8Sll3aCRsWIA/k/v9B99+OV0yOziCUGrbxOzo5G7/vvQqt9VZYF++NpJOZqhNtzOylY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8B552FEC; Wed, 4 Sep 2024 03:19:13 -0700 (PDT) Received: from [10.57.87.65] (unknown [10.57.87.65]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A01EC3F66E; Wed, 4 Sep 2024 03:18:45 -0700 (PDT) Message-ID: <069185e0-80db-46a7-8852-2381db28cc97@arm.com> Date: Wed, 4 Sep 2024 11:18:44 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/2] mm: Tidy up shmem mTHP controls and stats Content-Language: en-GB To: Barry Song , Baolin Wang Cc: Andrew Morton , Hugh Dickins , "Matthew Wilcox (Oracle)" , David Hildenbrand , Lance Yang , Gavin Shan , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20240808111849.651867-1-ryan.roberts@arm.com> <20240808111849.651867-3-ryan.roberts@arm.com> <747d1319-f746-4379-bf88-a0f6c3f558b4@linux.alibaba.com> <14823123-79e3-4c7d-8501-8c46c6ec13c7@arm.com> From: Ryan Roberts In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 03/09/2024 02:53, Barry Song wrote: > On Tue, Sep 3, 2024 at 1:15 PM Baolin Wang > wrote: >> >> >> >> On 2024/9/2 17:58, Ryan Roberts wrote: >>> Hi Baolin, >>> >>> Thanks for the review - I've been out on Paternity leave so only getting around >>> to replying now... >> >> No worries :) >> >>> On 09/08/2024 09:31, Baolin Wang wrote: >>>> >>>> >>>> On 2024/8/8 19:18, Ryan Roberts wrote: >>>>> Previously we had a situation where shmem mTHP controls and stats were >>>>> not exposed for some supported sizes and were exposed for some >>>>> unsupported sizes. So let's clean that up. >>>>> >>>>> Anon mTHP can support all large orders [2, PMD_ORDER]. But shmem can >>>>> support all large orders [1, MAX_PAGECACHE_ORDER]. However, per-size >>>>> shmem controls and stats were previously being exposed for all the anon >>>>> mTHP orders, meaning order-1 was not present, and for arm64 64K base >>>>> pages, orders 12 and 13 were exposed but were not supported internally. >>>>> >>>>> Tidy this all up by defining ctrl and stats attribute groups for anon >>>>> and file separately. Anon ctrl and stats groups are populated for all >>>>> orders in THP_ORDERS_ALL_ANON and file ctrl and stats groups are >>>>> populated for all orders in THP_ORDERS_ALL_FILE_DEFAULT. >>>>> >>>>> Additionally, create "any" ctrl and stats attribute groups which are >>>>> populated for all orders in (THP_ORDERS_ALL_ANON | >>>>> THP_ORDERS_ALL_FILE_DEFAULT). swpout stats use this since they apply to >>>>> anon and shmem. >>>>> >>>>> The side-effect of all this is that different hugepage-*kB directories >>>>> contain different sets of controls and stats, depending on which memory >>>>> types support that size. This approach is preferred over the >>>>> alternative, which is to populate dummy controls and stats for memory >>>>> types that do not support a given size. >>>>> >>>>> Signed-off-by: Ryan Roberts >>>>> --- >>>>> mm/huge_memory.c | 144 +++++++++++++++++++++++++++++++++++++---------- >>>>> 1 file changed, 114 insertions(+), 30 deletions(-) >>>>> >>>>> diff --git a/mm/huge_memory.c b/mm/huge_memory.c >>>>> index 0c3075ee00012..082d86b7c6c2f 100644 >>>>> --- a/mm/huge_memory.c >>>>> +++ b/mm/huge_memory.c >>>>> @@ -482,8 +482,8 @@ static void thpsize_release(struct kobject *kobj); >>>>> static DEFINE_SPINLOCK(huge_anon_orders_lock); >>>>> static LIST_HEAD(thpsize_list); >>>>> -static ssize_t thpsize_enabled_show(struct kobject *kobj, >>>>> - struct kobj_attribute *attr, char *buf) >>>>> +static ssize_t anon_enabled_show(struct kobject *kobj, >>>>> + struct kobj_attribute *attr, char *buf) >>>>> { >>>>> int order = to_thpsize(kobj)->order; >>>>> const char *output; >>>>> @@ -500,9 +500,9 @@ static ssize_t thpsize_enabled_show(struct kobject *kobj, >>>>> return sysfs_emit(buf, "%s\n", output); >>>>> } >>>>> -static ssize_t thpsize_enabled_store(struct kobject *kobj, >>>>> - struct kobj_attribute *attr, >>>>> - const char *buf, size_t count) >>>>> +static ssize_t anon_enabled_store(struct kobject *kobj, >>>>> + struct kobj_attribute *attr, >>>>> + const char *buf, size_t count) >>>>> { >>>>> int order = to_thpsize(kobj)->order; >>>>> ssize_t ret = count; >>>>> @@ -544,19 +544,35 @@ static ssize_t thpsize_enabled_store(struct kobject *kobj, >>>>> return ret; >>>>> } >>>>> -static struct kobj_attribute thpsize_enabled_attr = >>>>> - __ATTR(enabled, 0644, thpsize_enabled_show, thpsize_enabled_store); >>>>> +static struct kobj_attribute anon_enabled_attr = >>>>> + __ATTR(enabled, 0644, anon_enabled_show, anon_enabled_store); >>>>> -static struct attribute *thpsize_attrs[] = { >>>>> - &thpsize_enabled_attr.attr, >>>>> +static struct attribute *anon_ctrl_attrs[] = { >>>>> + &anon_enabled_attr.attr, >>>>> + NULL, >>>>> +}; >>>>> + >>>>> +static const struct attribute_group anon_ctrl_attr_grp = { >>>>> + .attrs = anon_ctrl_attrs, >>>>> +}; >>>>> + >>>>> +static struct attribute *file_ctrl_attrs[] = { >>>>> #ifdef CONFIG_SHMEM >>>>> &thpsize_shmem_enabled_attr.attr, >>>>> #endif >>>>> NULL, >>>>> }; >>>>> -static const struct attribute_group thpsize_attr_group = { >>>>> - .attrs = thpsize_attrs, >>>>> +static const struct attribute_group file_ctrl_attr_grp = { >>>>> + .attrs = file_ctrl_attrs, >>>>> +}; >>>>> + >>>>> +static struct attribute *any_ctrl_attrs[] = { >>>>> + NULL, >>>>> +}; >>>>> + >>>>> +static const struct attribute_group any_ctrl_attr_grp = { >>>>> + .attrs = any_ctrl_attrs, >>>>> }; >>>> >>>> I wonder why adding a NULL group? >>> >>> It made everything a bit more generic and therefore extensible. Its my >>> preference to leave it as is, but will remove it if you insist. >> >> My preference is we should add it when necessary, but but I don't have a >> strong opinion. Let's see what other guys prefer, David, Barry? > > I'm fine with either option. Adding a NULL control group makes it > easier for lazy > people like me to understand the current status, as it clearly > indicates that there > isn't a shared control group for file, shmem, and anon at the moment. :-) Thanks for the feedback, I'm going to leave it as is in the next version then. > > Thanks > Barry