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Message-ID: <1bf1bc10-b44f-46a9-8a7d-c3318d7c9bb5@linux.alibaba.com>
Date: Thu, 5 Sep 2024 08:45:34 +0800
From: Baolin Wang <baolin.wang@...ux.alibaba.com>
To: Ryan Roberts <ryan.roberts@....com>,
Andrew Morton <akpm@...ux-foundation.org>, Hugh Dickins <hughd@...gle.com>,
"Matthew Wilcox (Oracle)" <willy@...radead.org>,
David Hildenbrand <david@...hat.com>, Barry Song <baohua@...nel.org>,
Lance Yang <ioworker0@...il.com>, Gavin Shan <gshan@...hat.com>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH v3 2/2] mm: Tidy up shmem mTHP controls and stats
On 2024/9/4 18:47, Ryan Roberts wrote:
> Hi Andrew,
>
>
> 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 <ryan.roberts@....com>
>>> ---
>>> 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?
>>
>>> static const struct kobj_type thpsize_ktype = {
>>> @@ -595,64 +611,132 @@ DEFINE_MTHP_STAT_ATTR(anon_fault_fallback,
>>> MTHP_STAT_ANON_FAULT_FALLBACK);
>>> DEFINE_MTHP_STAT_ATTR(anon_fault_fallback_charge,
>>> MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE);
>>> DEFINE_MTHP_STAT_ATTR(swpout, MTHP_STAT_SWPOUT);
>>> DEFINE_MTHP_STAT_ATTR(swpout_fallback, MTHP_STAT_SWPOUT_FALLBACK);
>>> +#ifdef CONFIG_SHMEM
>>> DEFINE_MTHP_STAT_ATTR(shmem_alloc, MTHP_STAT_SHMEM_ALLOC);
>>> DEFINE_MTHP_STAT_ATTR(shmem_fallback, MTHP_STAT_SHMEM_FALLBACK);
>>> DEFINE_MTHP_STAT_ATTR(shmem_fallback_charge, MTHP_STAT_SHMEM_FALLBACK_CHARGE);
>>> +#endif
>>> 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,
>>> +#ifndef CONFIG_SHMEM
>>> &swpout_attr.attr,
>>> &swpout_fallback_attr.attr,
>>> - &shmem_alloc_attr.attr,
>>> - &shmem_fallback_attr.attr,
>>> - &shmem_fallback_charge_attr.attr,
>>> +#endif
>>> &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,
>>> +#endif
>>> + NULL,
>>> +};
>>> +
>>> +static struct attribute_group file_stats_attr_grp = {
>>> + .name = "stats",
>>> + .attrs = file_stats_attrs,
>>> +};
>>> +
>>> +static struct attribute *any_stats_attrs[] = {
>>> +#ifdef CONFIG_SHMEM
>>> + &swpout_attr.attr,
>>> + &swpout_fallback_attr.attr,
>>> +#endif
>>
>> Sorry I did not point it out in early version. I think file pages and shmem can
>> also be split, while 'split_deferred' is only for anonymous page. So I think the
>> any_stats_attrs should be:
>> static struct attribute *any_stats_attrs[] = {
>> #ifdef CONFIG_SHMEM
>> &swpout_attr.attr,
>> &swpout_fallback_attr.attr,
>> #endif
>> &split_attr.attr,
>> &split_failed_attr.attr,
>> NULL,
>> };
>
> Could you please squash the following into this patch, which is already in
> mm-unstable? I'm hoping this sufficient and I don't need to send a whole new
> revision since there are changes on top of this in mm-unstable, which makes
> things tricky.
>
> ----8<-----
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 382938e46f96f..5905957b1f70d 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -631,8 +631,6 @@ static struct attribute *anon_stats_attrs[] = {
> &swpout_attr.attr,
> &swpout_fallback_attr.attr,
> #endif
> - &split_attr.attr,
> - &split_failed_attr.attr,
> &split_deferred_attr.attr,
> &nr_anon_attr.attr,
> &nr_anon_partially_mapped_attr.attr,
> @@ -663,6 +661,8 @@ static struct attribute *any_stats_attrs[] = {
> &swpout_attr.attr,
> &swpout_fallback_attr.attr,
> #endif
> + &split_attr.attr,
> + &split_failed_attr.attr,
> NULL,
> };
The change looks good to me. Feel free to add
Reviewed-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
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