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Wed, 6 Mar 2024 22:23:20 +0800 Message-ID: <44c0fb50-3a0d-428a-8310-3e8d2eb1a53c@huawei.com> Date: Wed, 6 Mar 2024 22:23:19 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 6/7] mm,page_owner: Filter out stacks by a threshold Content-Language: en-US To: Oscar Salvador , Andrew Morton CC: , , Michal Hocko , Vlastimil Babka , Marco Elver , Andrey Konovalov , Alexander Potapenko References: <20240215215907.20121-1-osalvador@suse.de> <20240215215907.20121-7-osalvador@suse.de> From: Kefeng Wang In-Reply-To: <20240215215907.20121-7-osalvador@suse.de> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm100001.china.huawei.com (7.185.36.93) X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 62189C0015 X-Stat-Signature: am8wmi5ara1mzdx7winxnwr3dwydo1t1 X-Rspam-User: X-HE-Tag: 1709735005-373788 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi On 2024/2/16 5:59, Oscar Salvador wrote: > We want to be able to filter out the stacks based on a threshold we can > can tune. > By writing to 'count_threshold' file, we can adjust the threshold value. > > Signed-off-by: Oscar Salvador > Reviewed-by: Vlastimil Babka > --- > mm/page_owner.c | 23 ++++++++++++++++++++++- > 1 file changed, 22 insertions(+), 1 deletion(-) > > diff --git a/mm/page_owner.c b/mm/page_owner.c > index e99fbf822dd6..e56c1e92eccf 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -846,6 +846,8 @@ static void *stack_next(struct seq_file *m, void *v, loff_t *ppos) > return stack; > } > > +static unsigned long page_owner_stack_threshold; > + > static int stack_print(struct seq_file *m, void *v) > { > int i, stack_count; > @@ -858,7 +860,8 @@ static int stack_print(struct seq_file *m, void *v) > entries = stack_record->entries; > stack_count = refcount_read(&stack_record->count) - 1; > > - if (!nr_entries || nr_entries < 0 || stack_count < 1) > + if (!nr_entries || nr_entries < 0 || stack_count < 1 || > + stack_count < page_owner_stack_threshold) > return 0; > > for (i = 0; i < nr_entries; i++) > @@ -891,6 +894,22 @@ static const struct file_operations page_owner_stack_operations = { > .release = seq_release, > }; > > +static int page_owner_threshold_get(void *data, u64 *val) > +{ > + *val = READ_ONCE(page_owner_stack_threshold); > + return 0; > +} > + > +static int page_owner_threshold_set(void *data, u64 val) > +{ > + WRITE_ONCE(page_owner_stack_threshold, val); > + return 0; > +} no need READ/WRITE_ONCE between get/set, since simple_attr_read/write() with a mutex, but set and stack_print could date race > + > +DEFINE_SIMPLE_ATTRIBUTE(proc_page_owner_threshold, &page_owner_threshold_get, > + &page_owner_threshold_set, "%llu"); %llu\n" In addition, since we have a stack_list, could we add a new feature to dump stack info with threshold with OOM notifier, because many users directly call alloc_page family, which makes it too difficult to debug during OOM. Thanks > + > + > static int __init pageowner_init(void) > { > struct dentry *dir; > @@ -905,6 +924,8 @@ static int __init pageowner_init(void) > dir = debugfs_create_dir("page_owner_stacks", NULL); > debugfs_create_file("show_stacks", 0400, dir, NULL, > &page_owner_stack_operations); > + debugfs_create_file("count_threshold", 0600, dir, NULL, > + &proc_page_owner_threshold); > > return 0; > }