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 9A36314F9C9 for ; Mon, 22 Jul 2024 07:33:09 +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=1721633592; cv=none; b=qtWb7FVQbjgzbE08WlwDMtR/IXIE8OwfxoXB6ZQ21sP6eammKohL/S5CCb7E/7upI7VxF7tZn8fQzE/yg5rzx1HG3FN764kTvd05YphCpictEX17bzozwzeuY13rG2JC4GxJyW23xWvdQg2m1sbMG5/X8GhRB8Zf7fgAp0H07zE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721633592; c=relaxed/simple; bh=+iiQPCCgQmiZG1Rk8Q8zrrvUuq9+0lsyFBwnBEm+1wA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=MLGa5u3utohl2hMCTbjPnTAP6bVk2cPOCE6ZWLLh55wxwqmuKKoHYmy0RkaTrIt0NlUrkiq6v8TOTPSP06cWbyyk6IlW0UzvaLoVARI3Ab4AqFLX39sYlIz8XXLKBCR5y6ADlM7erZEHLcS2/vVygtz+3ftGoadcBZ4PJ9j5JOw= 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 3ABCEFEC; Mon, 22 Jul 2024 00:33:34 -0700 (PDT) Received: from [10.57.77.243] (unknown [10.57.77.243]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 541E53F766; Mon, 22 Jul 2024 00:33:07 -0700 (PDT) Message-ID: <1732c37b-ab9d-47f7-8bfe-cc7992b632cf@arm.com> Date: Mon, 22 Jul 2024 08:33:05 +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 v2 2/3] mm: Tidy up shmem mTHP controls and stats Content-Language: en-GB To: Baolin Wang , Andrew Morton , Hugh Dickins , Jonathan Corbet , "Matthew Wilcox (Oracle)" , David Hildenbrand , Barry Song , Lance Yang , Gavin Shan Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20240716135907.4047689-1-ryan.roberts@arm.com> <20240716135907.4047689-3-ryan.roberts@arm.com> <9a7c863d-b64e-4278-bb5b-db777736ab6e@linux.alibaba.com> From: Ryan Roberts In-Reply-To: <9a7c863d-b64e-4278-bb5b-db777736ab6e@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 22/07/2024 07:14, Baolin Wang wrote: > > > On 2024/7/16 21:59, 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. > > Make sense. > >> >> 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. > > OK. > >> >> Signed-off-by: Ryan Roberts >> --- >>   mm/huge_memory.c | 110 ++++++++++++++++++++++++++++++++++------------- >>   1 file changed, 80 insertions(+), 30 deletions(-) >> >> diff --git a/mm/huge_memory.c b/mm/huge_memory.c >> index f4be468e06a4..578ac212c172 100644 >> --- a/mm/huge_memory.c >> +++ b/mm/huge_memory.c >> @@ -463,8 +463,8 @@ 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; >> @@ -481,9 +481,9 @@ 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; >> @@ -525,19 +525,27 @@ 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 const struct kobj_type thpsize_ktype = { >> @@ -583,57 +591,99 @@ DEFINE_MTHP_STAT_ATTR(split, MTHP_STAT_SPLIT); >>   DEFINE_MTHP_STAT_ATTR(split_failed, MTHP_STAT_SPLIT_FAILED); >>   DEFINE_MTHP_STAT_ATTR(split_deferred, MTHP_STAT_SPLIT_DEFERRED); >>   -static struct attribute *stats_attrs[] = { >> +static struct attribute *anon_stats_attrs[] = { >>       &anon_fault_alloc_attr.attr, >>       &anon_fault_fallback_attr.attr, >>       &anon_fault_fallback_charge_attr.attr, >>       &swpout_attr.attr, >>       &swpout_fallback_attr.attr, >> -    &shmem_alloc_attr.attr, >> -    &shmem_fallback_attr.attr, >> -    &shmem_fallback_charge_attr.attr, >>       &split_attr.attr, >>       &split_failed_attr.attr, >>       &split_deferred_attr.attr, >>       NULL, >>   }; >>   -static struct attribute_group stats_attr_group = { >> +static struct attribute_group anon_stats_attr_grp = { >> +    .name = "stats", >> +    .attrs = anon_stats_attrs, >> +}; >> + >> +static struct attribute *file_stats_attrs[] = { >> +#ifdef CONFIG_SHMEM >> +    &shmem_alloc_attr.attr, >> +    &shmem_fallback_attr.attr, >> +    &shmem_fallback_charge_attr.attr, > > Shmem should also support swpout_* counters. OK, so to put it another way, swpout_* stats are required all orders in (THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE_DEFAULT) if CONFIG_SHMEM is defined, else all orders in THP_ORDERS_ALL_ANON. Have I understood correctly? If so, I'll fix that in the next version.