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charset=UTF-8 Date: Sat, 10 Oct 2026 07:42:42 -0400 Message-Id: Cc: , , , , , To: "Kanishka Solanki" , , From: "Zi Yan" Subject: Re: [PATCH] mm/page_owner: make page_owner stack depth runtime configurable X-Mailer: aerc 0.22.0 References: <20261010093843.103169-1-kanishkasolanki456s@gmail.com> In-Reply-To: <20261010093843.103169-1-kanishkasolanki456s@gmail.com> X-ClientProxiedBy: YQBPR01CA0160.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c01:7e::29) To IA0PR12MB8374.namprd12.prod.outlook.com (2603:10b6:208:40e::7) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: IA0PR12MB8374:EE_|PH0PR12MB7957:EE_ X-MS-Office365-Filtering-Correlation-Id: 1ac95a5f-3ce6-48a1-4b6e-08df26c3992d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|23010399003|376014|22082099003|18002099003|56012099006|6133799003|10067099003|11063799006|261009223027099003; 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This allows users to configure > the stack recording depth between 1 and 64 at boot or runtime via sysfs, > while preventing unbounded stack usage. What is your motivation? If you see page owner stack gets cutoff due to insufficient depth, explain your use cases first. > > Signed-off-by: Kanishka > Signed-off-by: Kanishka Solanki > --- > mm/page_owner.c | 15 ++++++++------- > 1 file changed, 8 insertions(+), 7 deletions(-) > > diff --git a/mm/page_owner.c b/mm/page_owner.c > index fbbda7ba914b..fcb584070f1d 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -15,11 +15,10 @@ > =20 > #include "page_alloc.h" > =20 > -/* > - * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack) > - * to use off stack temporal storage > - */ > -#define PAGE_OWNER_STACK_DEPTH (16) > +#define PAGE_OWNER_STACK_DEPTH_MAX (64) This uses more stack. Do not do this. > + > +static unsigned int page_owner_stack_depth =3D 16; > +module_param_named(stack_depth, page_owner_stack_depth, uint, 0644); > =20 > struct page_owner { > unsigned short order; > @@ -172,15 +171,17 @@ static inline struct page_owner *get_page_owner(str= uct page_ext *page_ext) > =20 > static noinline depot_stack_handle_t save_stack(gfp_t flags) > { > - unsigned long entries[PAGE_OWNER_STACK_DEPTH]; > + unsigned long entries[PAGE_OWNER_STACK_DEPTH_MAX]; > depot_stack_handle_t handle; > unsigned int nr_entries; > + unsigned int max_entries; > =20 > if (current->in_page_owner) > return dummy_handle; > =20 > set_current_in_page_owner(); > - nr_entries =3D stack_trace_save(entries, ARRAY_SIZE(entries), 2); > + max_entries =3D min_t(unsigned int, page_owner_stack_depth, ARRAY_SIZE(= entries)); > + nr_entries =3D stack_trace_save(entries, max_entries, 2); > handle =3D stack_depot_save(entries, nr_entries, flags); > if (!handle) > handle =3D failure_handle; --=20 Best Regards, Yan, Zi