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McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , rcu@vger.kernel.org, linux-kernel@vger.kernel.org, openeuler Subject: Re: [PATCH v3 1/2] mm: Provide empty function for kmem_dump_obj() when CONFIG_PRINTK=n Message-ID: References: <20230802034518.1115-1-thunder.leizhen@huaweicloud.com> <20230802034518.1115-2-thunder.leizhen@huaweicloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230802034518.1115-2-thunder.leizhen@huaweicloud.com> X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: C05FC1C0007 X-Stat-Signature: tr9gofa7ypk6i8mfktupzf88zauhnmbb X-Rspam-User: X-HE-Tag: 1690948702-393202 X-HE-Meta: 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 0A8xuTC2 G8XLwiChaJL2xiRb9P2yT8kfJgDlLAZEHPoqhyAPMWFsScw3f5pXAFsJ+a8pf9nSFg1a0PxQ84watkmu0/k4TgHpLUxbfjVwNn8nvicuE0bsbQtlvl/z1DyVD8j/JfDYi8K+ET7Y0c3Zqo5VlEUDeDRdk0gjZCrL2ovyhqQvhD91n9REXFkEGs51WnlFsKkoX0/56Pyv5PHWJmjiQax4vjkbdDUSF+xo6GltiG9/jqCy1nEsHCTIP27oGi7XsqRc2EqfigxDVtBXOH3Wzp4OpRAoXlykeM3RdL89oIO9jBDc0JzY+UQ1mkxLVBUz4N85M+XmD 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: On Wed, Aug 02, 2023 at 11:45:16AM +0800, thunder.leizhen@huaweicloud.com wrote: > +++ b/include/linux/slab.h > @@ -246,6 +246,9 @@ size_t ksize(const void *objp); > #ifdef CONFIG_PRINTK > bool kmem_valid_obj(void *object); > void kmem_dump_obj(void *object); > +#else > +static inline bool kmem_valid_obj(void *object) { return false; } That is very confusing. kmem_valid_obj() looks like a function which should exist regardless of CONFIG_PRINTK and to have it always return false if CONFIG_PRINTK isn't set seems weird. I see we have one caller of kmem_valid_obj() right now. Which means it shouldn't be an EXPORT_SYMBOL since that caller is not a module. I think the right solution is to convert kmem_dump_obj() to work the same way as vmalloc_dump_obj(). ie: +++ b/mm/util.c @@ -1057,11 +1057,8 @@ void mem_dump_obj(void *object) { const char *type; - if (kmem_valid_obj(object)) { - kmem_dump_obj(object); + if (kmem_dump_obj(object)) return; - } - if (vmalloc_dump_obj(object)) return; ... with corresponding changes to eliminate kmem_valid_obj() as a symbol.