On 10/04/2019 01:55 PM, David Hildenbrand wrote: > On 03.10.19 14:14, Qian Cai wrote: >> >> >>> On Oct 3, 2019, at 8:01 AM, Anshuman Khandual <Anshuman.Khandual@xxxxxxx> wrote: >>> >>> Will something like this be better ? >> >> Not really. dump_page() will dump PageCompound information anyway, so it is trivial to figure out if went in that path. >> > > I agree, I use the dump_page() output frequently to identify PG_reserved > pages. No need to duplicate that. Here in this path there is a reserved page which is preventing offlining a memory section but unfortunately dump_page() does not print page->flags for a reserved page pinned there possibly through memblock_reserve() during boot. __offline_pages() start_isolate_page_range() set_migratetype_isolate() has_unmovable_pages() dump_page() [ 64.920970] ------------[ cut here ]------------ [ 64.921718] WARNING: CPU: 16 PID: 1116 at mm/page_alloc.c:8298 has_unmovable_pages+0x274/0x2a8 [ 64.923110] Modules linked in: [ 64.923634] CPU: 16 PID: 1116 Comm: bash Not tainted 5.5.0-rc6-00006-gca544f2a11ae-dirty #281 [ 64.925102] Hardware name: linux,dummy-virt (DT) [ 64.925905] pstate: 60400085 (nZCv daIf +PAN -UAO) [ 64.926742] pc : has_unmovable_pages+0x274/0x2a8 [ 64.927554] lr : has_unmovable_pages+0x298/0x2a8 [ 64.928359] sp : ffff800014fd3a00 [ 64.928944] x29: ffff800014fd3a00 x28: fffffe0017640000 [ 64.929875] x27: 0000000000000000 x26: ffff0005fcfcda00 [ 64.930810] x25: 0000000000640000 x24: 0000000000000003 [ 64.931736] x23: 0000000019840000 x22: 0000000000001380 [ 64.932667] x21: ffff800011259000 x20: ffff0005fcfcda00 [ 64.933588] x19: 0000000000661000 x18: 0000000000000010 [ 64.934514] x17: 0000000000000000 x16: 0000000000000000 [ 64.935454] x15: ffffffffffffffff x14: ffff8000118498c8 [ 64.936377] x13: ffff800094fd3797 x12: ffff800014fd379f [ 64.937304] x11: ffff800011861000 x10: ffff800014fd3720 [ 64.938226] x9 : 00000000ffffffd0 x8 : ffff8000106a60d0 [ 64.939156] x7 : 0000000000000000 x6 : ffff0005fc6261b0 [ 64.940078] x5 : ffff0005fc6261b0 x4 : 0000000000000000 [ 64.941003] x3 : ffff0005fc62cf80 x2 : ffffffffffffec80 [ 64.941927] x1 : ffff800011141b58 x0 : ffff0005fcfcda00 [ 64.942857] Call trace: [ 64.943298] has_unmovable_pages+0x274/0x2a8 [ 64.944056] start_isolate_page_range+0x258/0x360 [ 64.944879] __offline_pages+0xf4/0x9e8 [ 64.945554] offline_pages+0x10/0x18 [ 64.946189] memory_block_action+0x40/0x1a0 [ 64.946929] memory_subsys_offline+0x4c/0x78 [ 64.947679] device_offline+0x98/0xc8 [ 64.948328] unprobe_store+0xa8/0x158 [ 64.948976] dev_attr_store+0x14/0x28 [ 64.949628] sysfs_kf_write+0x40/0x50 [ 64.950273] kernfs_fop_write+0x108/0x218 [ 64.950983] __vfs_write+0x18/0x40 [ 64.951592] vfs_write+0xb0/0x1d0 [ 64.952175] ksys_write+0x64/0xe8 [ 64.952761] __arm64_sys_write+0x18/0x20 [ 64.953451] el0_svc_common.constprop.2+0x88/0x150 [ 64.954293] el0_svc_handler+0x20/0x80 [ 64.954963] el0_sync_handler+0x118/0x188 [ 64.955669] el0_sync+0x140/0x180 [ 64.956256] ---[ end trace b162b4d1cbea304d ]--- [ 64.957063] page:fffffe0017640000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 [ 64.958489] raw: 1ffff80000001000 fffffe0017640008 fffffe0017640008 0000000000000000 [ 64.959839] raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 [ 64.961174] page dumped because: unmovable page The reason is dump_page() does not print page->flags universally and only does so for KSM, Anon and File pages while excluding reserved pages at boot. Wondering should not we make printing page->flags universal ? - Anshuman
