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[71.184.117.43]) by smtp.gmail.com with ESMTPSA id a20sm29689919qth.88.2019.04.16.08.34.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 16 Apr 2019 08:34:50 -0700 (PDT) Subject: Re: [PATCH] slab: remove store_stackinfo() To: Vlastimil Babka , akpm@linux-foundation.org Cc: luto@kernel.org, jpoimboe@redhat.com, sean.j.christopherson@intel.com, penberg@kernel.org, rientjes@google.com, tglx@linutronix.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20190416142258.18694-1-cai@lca.pw> <902fed9c-9655-a241-677d-5fa11b6c95a1@suse.cz> From: Qian Cai Message-ID: <332fc776-65fa-eee6-e15d-2d872bd9d220@lca.pw> Date: Tue, 16 Apr 2019 11:34:49 -0400 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <902fed9c-9655-a241-677d-5fa11b6c95a1@suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/16/19 11:25 AM, Vlastimil Babka wrote: > On 4/16/19 4:22 PM, Qian Cai wrote: >> store_stackinfo() does not seem used in actual SLAB debugging. >> Potentially, it could be added to check_poison_obj() to provide more >> information, but this seems like an overkill due to the declining >> popularity of the SLAB, so just remove it instead. >> >> Signed-off-by: Qian Cai > > I've acked Thomas' version already which was narrower, but no objection > to remove more stuff on top of that. Linus (and I later in another > thread) already pointed out /proc/slab_allocators. It only takes a look > at add_caller() there to not regret removing that one. Well, with the 2 patches I sent a while back, /proc/slab_allocators is back to life on all arches (arm64, powerpc, and x86) which provides a little information that may still useful for debugging until SLAB is gone entirely. # cat /proc/slab_allocators xfs_ili: 92 kmem_zone_alloc+0x6c/0x100 [xfs] xfs_ifork: 2539 kmem_zone_alloc+0x6c/0x100 [xfs] xfs_log_ticket: 3 kmem_zone_alloc+0x6c/0x100 [xfs] sd_ext_cdb: 2 mempool_alloc_slab+0x1c/0x30 ip_fib_trie: 7 fib_insert_alias+0x11a/0x2b0 ip_fib_alias: 9 fib_table_insert+0x16d/0x510 eventpoll_pwq: 5 ep_ptable_queue_proc+0x3f/0xc0 inotify_inode_mark: 8 __x64_sys_inotify_add_watch+0x225/0x340 khugepaged_mm_slot: 6 __khugepaged_enter+0x36/0x190 file_lock_ctx: 23 locks_get_lock_context+0xf2/0x180 fsnotify_mark_connector: 79 fsnotify_add_mark_locked+0x117/0x460 task_delay_info: 509 __delayacct_tsk_init+0x1e/0x50 sigqueue: 2 __sigqueue_alloc+0xa8/0x130 kernfs_iattrs_cache: 122 __kernfs_iattrs+0x5c/0xf0 kernfs_node_cache: 28234 __kernfs_new_node.constprop.6+0x65/0x200 buffer_head: 1 alloc_buffer_head+0x21/0x70 nsproxy: 4 create_new_namespaces+0x36/0x1c0 vm_area_struct: 17 vm_area_alloc+0x1e/0x60 anon_vma_chain: 16 __anon_vma_prepare+0x3d/0x160 anon_vma: 18 __anon_vma_prepare+0xd2/0x160 Acpi-Operand: 2931 acpi_ut_allocate_object_desc_dbg+0x3e/0x69 Acpi-Namespace: 1618 acpi_ns_create_node+0x37/0x46 numa_policy: 47 __mpol_dup+0x3c/0x170 kmemleak_scan_area: 994 kmemleak_scan_area+0xa0/0x1e0 kmemleak_object: 513426 create_object+0x48/0x2c0 trace_event_file: 1650 trace_create_new_event+0x22/0x90 ftrace_event_field: 3198 __trace_define_field+0x36/0xc0 vmap_area: 890 alloc_vmap_area+0xaf/0x880 vmap_area: 663 alloc_vmap_area+0x2a3/0x880 vmap_area: 6 pcpu_get_vm_areas+0x277/0xbe0 vmap_area: 1 pcpu_get_vm_areas+0x689/0xbe0 vmap_area: 1 vmalloc_init+0x23d/0x26e debug_objects_cache: 15917 __debug_object_init+0x444/0x4e0 debug_objects_cache: 999 debug_objects_mem_init+0x7b/0x5a2 page->ptl: 1526 ptlock_alloc+0x1e/0x40