mm: lower the printk loglevel for __dump_page messages (e0392cf7) · Commits · 戴 / test

__dump_page messages use KERN_EMERG resp. KERN_ALERT loglevel (this is the case since 2004). Most callers of this function are really detecting a critical page state and BUG right after. On the other hand the function is called also from contexts which just want to inform about the page state and those would rather not disrupt logs that much (e.g. some systems route these messages to the normal console). Reduce the loglevel to KERN_WARNING to make dump_page easier to reuse for other contexts while those messages will still make it to the kernel log in most setups. Even if the loglevel setup filters warnings away those paths that are really critical already print the more targeted error or panic and that should make it to the kernel log. [mhocko@kernel.org: fix __dump_page()] Link: http://lkml.kernel.org/r/20181212142540.GA7378@dhcp22.suse.cz [akpm@linux-foundation.org: s/KERN_WARN/KERN_WARNING/, per Michal] Link: http://lkml.kernel.org/r/20181107101830.17405-3-mhocko@kernel.org Signed-off-by:

Michal Hocko <mhocko@suse.com> Reviewed-by:

Andrew Morton <akpm@linux-foundation.org> Reviewed-by:

Anshuman Khandual <anshuman.khandual@arm.com> Cc: Baoquan He <bhe@redhat.com> Cc: Oscar Salvador <OSalvador@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: William Kucharski <william.kucharski@oracle.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/debug.c

+10 −10

Original line number	Diff line number	Diff line
		@@ -54,7 +54,7 @@ void __dump_page(struct page page, const char reason)
		* dump_page() when detected.
		*/
		if (page_poisoned) {
		pr_emerg("page:%px is uninitialized and poisoned", page);
		pr_warn("page:%px is uninitialized and poisoned", page);
		goto hex_only;
		}

		@@ -65,39 +65,39 @@ void __dump_page(struct page page, const char reason)
		*/
		mapcount = PageSlab(page) ? 0 : page_mapcount(page);

		pr_emerg("page:%px count:%d mapcount:%d mapping:%px index:%#lx",
		pr_warn("page:%px count:%d mapcount:%d mapping:%px index:%#lx",
		page, page_ref_count(page), mapcount,
		page->mapping, page_to_pgoff(page));
		if (PageCompound(page))
		pr_cont(" compound_mapcount: %d", compound_mapcount(page));
		pr_cont("\n");
		if (PageAnon(page))
		pr_emerg("anon ");
		pr_warn("anon ");
		else if (PageKsm(page))
		pr_emerg("ksm ");
		pr_warn("ksm ");
		else if (mapping) {
		pr_emerg("%ps ", mapping->a_ops);
		pr_warn("%ps ", mapping->a_ops);
		if (mapping->host->i_dentry.first) {
		struct dentry *dentry;
		dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias);
		pr_emerg("name:\"%pd\" ", dentry);
		pr_warn("name:\"%pd\" ", dentry);
		}
		}
		BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);

		pr_emerg("flags: %#lx(%pGp)\n", page->flags, &page->flags);
		pr_warn("flags: %#lx(%pGp)\n", page->flags, &page->flags);

		hex_only:
		print_hex_dump(KERN_ALERT, "raw: ", DUMP_PREFIX_NONE, 32,
		print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
		sizeof(unsigned long), page,
		sizeof(struct page), false);

		if (reason)
		pr_alert("page dumped because: %s\n", reason);
		pr_warn("page dumped because: %s\n", reason);

		#ifdef CONFIG_MEMCG
		if (!page_poisoned && page->mem_cgroup)
		pr_alert("page->mem_cgroup:%px\n", page->mem_cgroup);
		pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup);
		#endif
		}

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