From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 848BBC3A589 for ; Tue, 20 Aug 2019 13:18:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5089022DA9 for ; Tue, 20 Aug 2019 13:18:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5089022DA9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 813936B000A; Tue, 20 Aug 2019 09:18:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 28C546B000E; Tue, 20 Aug 2019 09:18:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EDFEA6B026B; Tue, 20 Aug 2019 09:18:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0108.hostedemail.com [216.40.44.108]) by kanga.kvack.org (Postfix) with ESMTP id A982F6B0010 for ; Tue, 20 Aug 2019 09:18:41 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 287EC181AC9C9 for ; Tue, 20 Aug 2019 13:18:41 +0000 (UTC) X-FDA: 75842860842.24.taste05_1190a18866945 X-HE-Tag: taste05_1190a18866945 X-Filterd-Recvd-Size: 5618 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf16.hostedemail.com (Postfix) with ESMTP for ; Tue, 20 Aug 2019 13:18:40 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id E9EB9AD54; Tue, 20 Aug 2019 13:18:38 +0000 (UTC) From: Vlastimil Babka To: linux-mm@kvack.org, Andrew Morton Cc: linux-kernel@vger.kernel.org, "Kirill A. Shutemov" , Michal Hocko , Mel Gorman , Matthew Wilcox , Vlastimil Babka Subject: [PATCH v2 3/4] mm, page_owner: keep owner info when freeing the page Date: Tue, 20 Aug 2019 15:18:27 +0200 Message-Id: <20190820131828.22684-4-vbabka@suse.cz> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190820131828.22684-1-vbabka@suse.cz> References: <20190820131828.22684-1-vbabka@suse.cz> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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: For debugging purposes it might be useful to keep the owner info even aft= er page has been freed, and include it in e.g. dump_page() when detecting a = bad page state. For that, change the PAGE_EXT_OWNER flag meaning to "page own= er info has been set at least once" and add new PAGE_EXT_OWNER_ACTIVE for tr= acking whether page is supposed to be currently tracked allocated or free. Adjus= t dump_page() accordingly, distinguishing free and allocated pages. In the page_owner debugfs file, keep printing only allocated pages so that exist= ing scripts are not confused, and also because free pages are irrelevant for = the memory statistics or leak detection that's the typical use case of the fi= le, anyway. Signed-off-by: Vlastimil Babka --- include/linux/page_ext.h | 1 + mm/page_owner.c | 34 ++++++++++++++++++++++++---------- 2 files changed, 25 insertions(+), 10 deletions(-) diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h index 09592951725c..682fd465df06 100644 --- a/include/linux/page_ext.h +++ b/include/linux/page_ext.h @@ -18,6 +18,7 @@ struct page_ext_operations { =20 enum page_ext_flags { PAGE_EXT_OWNER, + PAGE_EXT_OWNER_ACTIVE, #if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT) PAGE_EXT_YOUNG, PAGE_EXT_IDLE, diff --git a/mm/page_owner.c b/mm/page_owner.c index 813fcb70547b..4a48e018dbdf 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -111,7 +111,7 @@ void __reset_page_owner(struct page *page, unsigned i= nt order) page_ext =3D lookup_page_ext(page + i); if (unlikely(!page_ext)) continue; - __clear_bit(PAGE_EXT_OWNER, &page_ext->flags); + __clear_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags); } } =20 @@ -168,6 +168,7 @@ static inline void __set_page_owner_handle(struct pag= e *page, page_owner->gfp_mask =3D gfp_mask; page_owner->last_migrate_reason =3D -1; __set_bit(PAGE_EXT_OWNER, &page_ext->flags); + __set_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags); =20 page_ext =3D lookup_page_ext(page + i); } @@ -243,6 +244,7 @@ void __copy_page_owner(struct page *oldpage, struct p= age *newpage) * the new page, which will be freed. */ __set_bit(PAGE_EXT_OWNER, &new_ext->flags); + __set_bit(PAGE_EXT_OWNER_ACTIVE, &new_ext->flags); } =20 void pagetypeinfo_showmixedcount_print(struct seq_file *m, @@ -302,7 +304,7 @@ void pagetypeinfo_showmixedcount_print(struct seq_fil= e *m, if (unlikely(!page_ext)) continue; =20 - if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) + if (!test_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags)) continue; =20 page_owner =3D get_page_owner(page_ext); @@ -413,21 +415,26 @@ void __dump_page_owner(struct page *page) mt =3D gfpflags_to_migratetype(gfp_mask); =20 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) { - pr_alert("page_owner info is not active (free page?)\n"); + pr_alert("page_owner info is not present (never set?)\n"); return; } =20 + if (test_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags)) + pr_alert("page_owner tracks the page as allocated\n"); + else + pr_alert("page_owner tracks the page as freed\n"); + + pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#= x(%pGg)\n", + page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask); + handle =3D READ_ONCE(page_owner->handle); if (!handle) { - pr_alert("page_owner info is not active (free page?)\n"); - return; + pr_alert("page_owner allocation stack trace missing\n"); + } else { + nr_entries =3D stack_depot_fetch(handle, &entries); + stack_trace_print(entries, nr_entries, 0); } =20 - nr_entries =3D stack_depot_fetch(handle, &entries); - pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pG= g)\n", - page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask); - stack_trace_print(entries, nr_entries, 0); - if (page_owner->last_migrate_reason !=3D -1) pr_alert("page has been migrated, last migrate reason: %s\n", migrate_reason_names[page_owner->last_migrate_reason]); @@ -489,6 +496,13 @@ read_page_owner(struct file *file, char __user *buf,= size_t count, loff_t *ppos) if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) continue; =20 + /* + * Although we do have the info about past allocation of free + * pages, it's not relevant for current memory usage. + */ + if (!test_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags)) + continue; + page_owner =3D get_page_owner(page_ext); =20 /* --=20 2.22.0