From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gir.skynet.ie (gir.skynet.ie [193.1.99.77]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 54799DDE16 for ; Wed, 5 Mar 2008 06:35:40 +1100 (EST) Date: Tue, 4 Mar 2008 19:35:33 +0000 From: Mel Gorman To: Pekka Enberg Subject: Re: [BUG] 2.6.25-rc3-mm1 kernel panic while bootup on powerpc () Message-ID: <20080304193532.GC9051@csn.ul.ie> References: <20080304011928.e8c82c0c.akpm@linux-foundation.org> <47CD4AB3.3080409@linux.vnet.ibm.com> <20080304103636.3e7b8fdd.akpm@linux-foundation.org> <47CDA081.7070503@cs.helsinki.fi> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 In-Reply-To: <47CDA081.7070503@cs.helsinki.fi> Cc: linux-mm@kvack.org, linuxppc-dev@ozlabs.org, Andrew Morton , Kamalesh Babulal List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On (04/03/08 21:18), Pekka Enberg didst pronounce: > Andrew Morton wrote: > >> [c000000009edf5f0] [c0000000000b56e4] .__alloc_pages_internal+0xf8/0x470 > >> [c000000009edf6e0] [c0000000000e0458] .kmem_getpages+0x8c/0x194 > >> [c000000009edf770] [c0000000000e1050] .fallback_alloc+0x194/0x254 > >> [c000000009edf820] [c0000000000e14b0] .kmem_cache_alloc+0xd8/0x144 > >> [c000000009edf8c0] [c0000000001fe0f8] .radix_tree_preload+0x50/0xd4 > >> [c000000009edf960] [c0000000000ad048] .add_to_page_cache+0x38/0x12c > >> [c000000009edfa00] [c0000000000ad158] .add_to_page_cache_lru+0x1c/0x4c > >> [c000000009edfa90] [c0000000000add58] .find_or_create_page+0x60/0xa8 > >> [c000000009edfb30] [c00000000011e478] .__getblk+0x140/0x310 > >> [c000000009edfc00] [c0000000001b78c4] > >.journal_get_descriptor_buffer+0x44/0xd8 > >> [c000000009edfca0] [c0000000001b236c] > >.journal_commit_transaction+0x948/0x1590 > >> [c000000009edfe00] [c0000000001b585c] .kjournald+0xf4/0x2ac > >> [c000000009edff00] [c00000000007ff4c] .kthread+0x84/0xd0 > >> [c000000009edff90] [c000000000028900] .kernel_thread+0x4c/0x68 > >> Instruction dump: > >> 7dc57378 48009575 60000000 2fa30000 419e0490 56c902d8 3c000018 7dd907b4 > >> 7ad2c7e2 7f890000 7c000026 5400fffe <0b000000> e93e8128 3b000000 > >80090000 > >/* Convert GFP flags to their corresponding migrate type */ > >static inline int allocflags_to_migratetype(gfp_t gfp_flags) > >{ > > WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK); > > > >Mel, Pekka: would you have some head-scratching time for this one please? > > What we have is __getblk() -> __getblk_slow() -> grow_buffers() -> > grow_dev_page() doing find_or_create_page() with __GFP_MOVABLE set. That > path then eventually does radix_tree_preload -> kmem_cache_alloc() to a > cache that has SLAB_RECLAIM_ACCOUNT set which implies __GFP_RECLAIMABLE > (for both SLAB and SLUB). So we oops there. > > I suspect the WARN_ON() is bogus although I really don't know that part > of the code all too well. Mel? > The warn-on is valid. A situation should not exist that allows both flags to be set. I suspect if remove-set_migrateflags.patch was reverted from -mm the warning would not trigger. Christoph, would it be reasonable to always clear __GFP_MOVABLE when __GFP_RECLAIMABLE is set for SLAB_RECLAIM_ACCOUNT. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab