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[71.184.117.43]) by smtp.gmail.com with ESMTPSA id e128sm13871914qkd.79.2019.04.11.14.31.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 11 Apr 2019 14:31:45 -0700 (PDT) From: Qian Cai To: akpm@linux-foundation.org Cc: mhocko@suse.com, osalvador@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qian Cai Subject: [PATCH] mm/hotplug: treat CMA pages as unmovable Date: Thu, 11 Apr 2019 17:31:24 -0400 Message-Id: <20190411213124.8254-1-cai@lca.pw> X-Mailer: git-send-email 2.20.1 (Apple Git-117) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When offlining a memory block that contains reserved CMA areas, it will set those page blocks migration type as MIGRATE_ISOLATE. Then, onlining will set them as MIGRATE_MOVABLE. As the results, those page blocks lose their original types, i.e., MIGRATE_CMA, and then it causes troubles like accounting for CMA areas becomes inconsist, # grep cma /proc/vmstat nr_free_cma 205824 # cat /sys/kernel/debug/cma/cma-kvm_cma/count 209920 Also, kmemleak still think those memory address are reserved but have already been used by the buddy allocator after onlining. Offlined Pages 4096 kmemleak: Cannot insert 0xc000201f7d040008 into the object search tree (overlaps existing) Call Trace: [c00000003dc2faf0] [c000000000884b2c] dump_stack+0xb0/0xf4 (unreliable) [c00000003dc2fb30] [c000000000424fb4] create_object+0x344/0x380 [c00000003dc2fbf0] [c0000000003d178c] __kmalloc_node+0x3ec/0x860 [c00000003dc2fc90] [c000000000319078] kvmalloc_node+0x58/0x110 [c00000003dc2fcd0] [c000000000484d9c] seq_read+0x41c/0x620 [c00000003dc2fd60] [c0000000004472bc] __vfs_read+0x3c/0x70 [c00000003dc2fd80] [c0000000004473ac] vfs_read+0xbc/0x1a0 [c00000003dc2fdd0] [c00000000044783c] ksys_read+0x7c/0x140 [c00000003dc2fe20] [c00000000000b108] system_call+0x5c/0x70 kmemleak: Kernel memory leak detector disabled kmemleak: Object 0xc000201cc8000000 (size 13757317120): kmemleak: comm "swapper/0", pid 0, jiffies 4294937297 kmemleak: min_count = -1 kmemleak: count = 0 kmemleak: flags = 0x5 kmemleak: checksum = 0 kmemleak: backtrace: cma_declare_contiguous+0x2a4/0x3b0 kvm_cma_reserve+0x11c/0x134 setup_arch+0x300/0x3f8 start_kernel+0x9c/0x6e8 start_here_common+0x1c/0x4b0 kmemleak: Automatic memory scanning thread ended Signed-off-by: Qian Cai --- mm/page_alloc.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d96ca5bc555b..896db9241fa6 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8015,14 +8015,18 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count, * can still lead to having bootmem allocations in zone_movable. */ - /* - * CMA allocations (alloc_contig_range) really need to mark isolate - * CMA pageblocks even when they are not movable in fact so consider - * them movable here. - */ - if (is_migrate_cma(migratetype) && - is_migrate_cma(get_pageblock_migratetype(page))) - return false; + if (is_migrate_cma(get_pageblock_migratetype(page))) { + /* + * CMA allocations (alloc_contig_range) really need to mark + * isolate CMA pageblocks even when they are not movable in fact + * so consider them movable here. + */ + if (is_migrate_cma(migratetype)) + return false; + + pr_warn("page: %px is in CMA", page); + return true; + } pfn = page_to_pfn(page); for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) { -- 2.20.1 (Apple Git-117)