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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Shuah Khan , Randy Dunlap , Brendan Jackman , Johannes Weiner , Zi Yan , linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Zhen Ni Subject: [PATCH 4/8] mm/page_owner: Refactor memcg handling for cgroup filter support Date: Fri, 28 Aug 2026 11:13:35 +0800 Message-Id: <20260828031339.1270699-5-zhen.ni@easystack.cn> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20260828031339.1270699-1-zhen.ni@easystack.cn> References: <20260828031339.1270699-1-zhen.ni@easystack.cn> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-HM-Tid: 0aa0465c1cf80229kunma81ef96712a344 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFJQjdXWRgWCB1ZQUpXWS1ZQUlXWQ8JGhUIEh9ZQVkZHh4YVhlPSh9OT05JHh9PHVYVFA kWGhdVGRETFhoSFyQUDg9ZV1kYEgtZQVlJSkNVQk9VSkpDVUJLWVdZFhoPEhUdFFlBWU9LSFVKS0 lPT09IVUpLS1VKQktLWQY+ X-Stat-Signature: 4ghocfd1r9c5hbnxcb8whdq4u5sicesq X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 1083B180004 X-Rspam-User: X-HE-Tag: 1787886840-927503 X-HE-Meta: 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 +4QL/iHk 0kHgxfOVfFqZGUXQLmM+0BtzgKAjcExeuKM2BQcXRGI5GdgFF/sJtY8NLz86C2EidXD6wzjeyDBorXhYNBmOid8IzB/j277GMWAZC69tzkfSL5quJaeqxX0RPO1UwPMnCVzhgRzCHcdjOROwV5TCrgusTdd/oHe557s0AgttEyIrZFOfZ00VUNmt/iwacICto5nCNFDQQQ01/Jk3UcxmWAsDlTdftcNenmkZ8bqpFKpjVY0I= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Extract memcg information retrieval from printing logic to prepare for cgroup filtering support. Introduce struct memcg_info to hold cgroup data that can be reused for both display output and filtering decisions. No functional change - output behavior unchanged. Signed-off-by: Zhen Ni --- mm/page_owner.c | 62 +++++++++++++++++++++++++++++++++++-------------- 1 file changed, 44 insertions(+), 18 deletions(-) diff --git a/mm/page_owner.c b/mm/page_owner.c index 7cd533682054..09cfad10a7df 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -69,6 +69,13 @@ static const char * const page_owner_print_mode_strings[] = { [PAGE_OWNER_PRINT_STACK_HANDLE] = "stack_handle", }; +struct memcg_info { + char name[80]; + bool is_slab; + bool is_objcg; + bool is_online; +}; + /* PID_MAX_LIMIT = 4,194,304 (7 decimal digits) */ #define PID_MAX_DIGITS 7 #define MAX_FILTER_PIDS 16 @@ -573,16 +580,13 @@ void pagetypeinfo_showmixedcount_print(struct seq_file *m, #ifdef CONFIG_MEMCG /* - * Looking for memcg information and print it out + * Get memcg information from page */ -static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret, - struct page *page) +static void get_page_memcg_info(struct page *page, struct memcg_info *info) { unsigned long memcg_data; struct obj_cgroup *objcg; struct mem_cgroup *memcg; - bool online; - char name[80]; rcu_read_lock(); memcg_data = READ_ONCE(page->memcg_data); @@ -590,8 +594,7 @@ static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret, goto out_unlock; if (memcg_data & MEMCG_DATA_OBJEXTS) { - ret += scnprintf(kbuf + ret, count - ret, - "Slab cache page\n"); + info->is_slab = true; goto out_unlock; } @@ -600,21 +603,38 @@ static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret, if (!memcg) goto out_unlock; - online = css_is_online(&memcg->css); - cgroup_name(memcg->css.cgroup, name, sizeof(name)); - ret += scnprintf(kbuf + ret, count - ret, - "Charged %sto %smemcg %s\n", - (memcg_data & MEMCG_DATA_KMEM) ? "(via objcg) " : "", - online ? "" : "offline ", - name); + info->is_objcg = (memcg_data & MEMCG_DATA_KMEM) != 0; + info->is_online = css_is_online(&memcg->css); + cgroup_name(memcg->css.cgroup, info->name, sizeof(info->name)); out_unlock: rcu_read_unlock(); +} + +/* + * Print memcg information from memcg_info + */ +static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret, + const struct memcg_info *info) +{ + if (!info) + return ret; + + if (info->is_slab) + ret += scnprintf(kbuf + ret, count - ret, + "Slab cache page\n"); + + if (info->name[0]) + ret += scnprintf(kbuf + ret, count - ret, + "Charged %sto %smemcg %s\n", + info->is_objcg ? "(via objcg) " : "", + info->is_online ? "" : "offline ", + info->name); return ret; } #else static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret, - struct page *page) + const struct memcg_info *info) { return ret; } @@ -624,7 +644,8 @@ static ssize_t print_page_owner(char __user *buf, size_t count, unsigned long pfn, struct page *page, struct page_owner *page_owner, depot_stack_handle_t handle, - struct page_owner_filter_state *state) + struct page_owner_filter_state *state, + const struct memcg_info *memcg_info) { int ret, pageblock_mt, page_mt; char *kbuf; @@ -674,7 +695,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, migrate_reason_names[page_owner->last_migrate_reason]); } - ret = print_page_owner_memcg(kbuf, count, ret, page); + ret = print_page_owner_memcg(kbuf, count, ret, memcg_info); ret += snprintf(kbuf + ret, count - ret, "\n"); if (ret >= count) @@ -777,6 +798,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) * user through copy_to_user() or GFP_KERNEL allocations. */ struct page_owner page_owner_tmp; + struct memcg_info memcg_info = {}; /* * If the new page is in a new MAX_ORDER_NR_PAGES area, @@ -876,13 +898,17 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) goto ext_put_continue; } +#ifdef CONFIG_MEMCG + get_page_memcg_info(page, &memcg_info); +#endif + /* Record the next PFN to read in the file offset */ *ppos = pfn + 1; page_owner_tmp = *page_owner; page_ext_put(page_ext); return print_page_owner(buf, count, pfn, page, - &page_owner_tmp, handle, state); + &page_owner_tmp, handle, state, &memcg_info); ext_put_continue: page_ext_put(page_ext); cond_resched(); -- 2.20.1