Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755764AbbHYOD0 (ORCPT ); Tue, 25 Aug 2015 10:03:26 -0400 Received: from mail-wi0-f180.google.com ([209.85.212.180]:37740 "EHLO mail-wi0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755729AbbHYODZ (ORCPT ); Tue, 25 Aug 2015 10:03:25 -0400 Date: Tue, 25 Aug 2015 16:03:22 +0200 From: Michal Hocko To: Yaowei Bai Cc: akpm@linux-foundation.org, mgorman@suse.de, vbabka@suse.cz, js1304@gmail.com, hannes@cmpxchg.org, alexander.h.duyck@redhat.com, sasha.levin@oracle.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm/page_alloc: add a helper function to check page before alloc/free Message-ID: <20150825140322.GC6285@dhcp22.suse.cz> References: <1440509190-3622-1-git-send-email-bywxiaobai@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1440509190-3622-1-git-send-email-bywxiaobai@163.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1638 Lines: 52 On Tue 25-08-15 21:26:30, Yaowei Bai wrote: [...] > static inline int check_new_page(struct page *page) > { > - const char *bad_reason = NULL; > - unsigned long bad_flags = 0; > - > - if (unlikely(page_mapcount(page))) > - bad_reason = "nonzero mapcount"; > - if (unlikely(page->mapping != NULL)) > - bad_reason = "non-NULL mapping"; > - if (unlikely(atomic_read(&page->_count) != 0)) > - bad_reason = "nonzero _count"; > - if (unlikely(page->flags & __PG_HWPOISON)) { > - bad_reason = "HWPoisoned (hardware-corrupted)"; > - bad_flags = __PG_HWPOISON; > - } You have removed this check AFAICS. Now looking at 39ad4f19671d ("mm: check __PG_HWPOISON separately from PAGE_FLAGS_CHECK_AT_*") I am not sure it is correct to check it in the free path as it was removed from the mask by this commit. > - if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) { > - bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set"; > - bad_flags = PAGE_FLAGS_CHECK_AT_PREP; > - } > -#ifdef CONFIG_MEMCG > - if (unlikely(page->mem_cgroup)) > - bad_reason = "page still charged to cgroup"; > -#endif > - if (unlikely(bad_reason)) { > - bad_page(page, bad_reason, bad_flags); > - return 1; > - } > - return 0; > + return check_one_page(page, PAGE_FLAGS_CHECK_AT_PREP); > } > > static int prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags, > -- > 1.9.1 > -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/