Continued from http://lkml.kernel.org/r/201702261530.JDD56292.OFOLFHQtVMJSOF@xxxxxxxxxxxxxxxxxxx : While I was testing a patch which avoids infinite too_many_isolated() loop in shrink_inactive_list(), I hit a lockup where WQ_MEM_RECLAIM threads got stuck waiting for memory allocation. I guess that we overlooked a basic thing about WQ_MEM_RECLAIM. WQ_MEM_RECLAIM helps only when the cause of failing to complete a work item is lack of "struct task_struct" to run that work item, for WQ_MEM_RECLAIM preallocates one "struct task_struct" so that the workqueue will not be blocked waiting for memory allocation for "struct task_struct". WQ_MEM_RECLAIM does not help when "struct task_struct" running that work item is blocked waiting for memory allocation (or is indirectly blocked on a lock where the owner of that lock is blocked waiting for memory allocation). That is, WQ_MEM_RECLAIM users must guarantee forward progress if memory allocation (including indirect memory allocation via locks/completions) is needed. In XFS, "xfs_mru_cache", "xfs-buf/%s", "xfs-data/%s", "xfs-conv/%s", "xfs-cil/%s", "xfs-reclaim/%s", "xfs-log/%s", "xfs-eofblocks/%s", "xfsalloc" and "xfsdiscard" workqueues are used, and all but "xfsdiscard" are WQ_MEM_RECLAIM workqueues. What I observed is at http://I-love.SAKURA.ne.jp/tmp/serial-20170226.txt.xz . I guess that the key of this lockup is that xfs-data/sda1 and xfs-eofblocks/s workqueues (which are RESCUER) got stuck waiting for memory allocation. ---------------------------------------- [ 1095.633625] MemAlloc: xfs-data/sda1(451) flags=0x4228060 switches=45509 seq=1 gfp=0x1604240(GFP_NOFS|__GFP_NOWARN|__GFP_COMP|__GFP_NOTRACK) order=0 delay=652073 [ 1095.633626] xfs-data/sda1 R running task 12696 451 2 0x00000000 [ 1095.633663] Workqueue: xfs-data/sda1 xfs_end_io [xfs] [ 1095.633665] Call Trace: [ 1095.633668] __schedule+0x336/0xe00 [ 1095.633671] schedule+0x3d/0x90 [ 1095.633672] schedule_timeout+0x20d/0x510 [ 1095.633675] ? lock_timer_base+0xa0/0xa0 [ 1095.633678] schedule_timeout_uninterruptible+0x2a/0x30 [ 1095.633680] __alloc_pages_slowpath+0x2b5/0xd95 [ 1095.633687] __alloc_pages_nodemask+0x3e4/0x460 [ 1095.633699] alloc_pages_current+0x97/0x1b0 [ 1095.633702] new_slab+0x4cb/0x6b0 [ 1095.633706] ___slab_alloc+0x3a3/0x620 [ 1095.633728] ? kmem_alloc+0x96/0x120 [xfs] [ 1095.633730] ? ___slab_alloc+0x5c6/0x620 [ 1095.633732] ? cpuacct_charge+0x38/0x1e0 [ 1095.633767] ? kmem_alloc+0x96/0x120 [xfs] [ 1095.633770] __slab_alloc+0x46/0x7d [ 1095.633773] __kmalloc+0x301/0x3b0 [ 1095.633802] kmem_alloc+0x96/0x120 [xfs] [ 1095.633804] ? kfree+0x1fa/0x330 [ 1095.633842] xfs_log_commit_cil+0x489/0x710 [xfs] [ 1095.633864] __xfs_trans_commit+0x83/0x260 [xfs] [ 1095.633883] xfs_trans_commit+0x10/0x20 [xfs] [ 1095.633901] __xfs_setfilesize+0xdb/0x240 [xfs] [ 1095.633936] xfs_setfilesize_ioend+0x89/0xb0 [xfs] [ 1095.633954] ? xfs_setfilesize_ioend+0x5/0xb0 [xfs] [ 1095.633971] xfs_end_io+0x81/0x110 [xfs] [ 1095.633973] process_one_work+0x22b/0x760 [ 1095.633975] ? process_one_work+0x194/0x760 [ 1095.633997] rescuer_thread+0x1f2/0x3d0 [ 1095.634002] kthread+0x10f/0x150 [ 1095.634003] ? worker_thread+0x4b0/0x4b0 [ 1095.634004] ? kthread_create_on_node+0x70/0x70 [ 1095.634007] ret_from_fork+0x31/0x40 [ 1095.634013] MemAlloc: xfs-eofblocks/s(456) flags=0x4228860 switches=15435 seq=1 gfp=0x1400240(GFP_NOFS|__GFP_NOWARN) order=0 delay=293074 [ 1095.634014] xfs-eofblocks/s R running task 12032 456 2 0x00000000 [ 1095.634037] Workqueue: xfs-eofblocks/sda1 xfs_eofblocks_worker [xfs] [ 1095.634038] Call Trace: [ 1095.634040] ? _raw_spin_lock+0x3d/0x80 [ 1095.634042] ? vmpressure+0xd0/0x120 [ 1095.634044] ? vmpressure+0xd0/0x120 [ 1095.634047] ? vmpressure_prio+0x21/0x30 [ 1095.634049] ? do_try_to_free_pages+0x70/0x300 [ 1095.634052] ? try_to_free_pages+0x131/0x3f0 [ 1095.634058] ? __alloc_pages_slowpath+0x3ec/0xd95 [ 1095.634065] ? __alloc_pages_nodemask+0x3e4/0x460 [ 1095.634069] ? alloc_pages_current+0x97/0x1b0 [ 1095.634111] ? xfs_buf_allocate_memory+0x160/0x2a3 [xfs] [ 1095.634133] ? xfs_buf_get_map+0x2be/0x480 [xfs] [ 1095.634169] ? xfs_buf_read_map+0x2c/0x400 [xfs] [ 1095.634204] ? xfs_trans_read_buf_map+0x186/0x830 [xfs] [ 1095.634222] ? xfs_btree_read_buf_block.constprop.34+0x78/0xc0 [xfs] [ 1095.634239] ? xfs_btree_lookup_get_block+0x8a/0x180 [xfs] [ 1095.634257] ? xfs_btree_lookup+0xd0/0x3f0 [xfs] [ 1095.634296] ? kmem_zone_alloc+0x96/0x120 [xfs] [ 1095.634299] ? _raw_spin_unlock+0x27/0x40 [ 1095.634315] ? xfs_bmbt_lookup_eq+0x1f/0x30 [xfs] [ 1095.634348] ? xfs_bmap_del_extent+0x1b2/0x1610 [xfs] [ 1095.634380] ? kmem_zone_alloc+0x96/0x120 [xfs] [ 1095.634400] ? __xfs_bunmapi+0x4db/0xda0 [xfs] [ 1095.634421] ? xfs_bunmapi+0x2b/0x40 [xfs] [ 1095.634459] ? xfs_itruncate_extents+0x1df/0x780 [xfs] [ 1095.634502] ? xfs_rename+0xc70/0x1080 [xfs] [ 1095.634525] ? xfs_free_eofblocks+0x1c4/0x230 [xfs] [ 1095.634546] ? xfs_inode_free_eofblocks+0x18d/0x280 [xfs] [ 1095.634565] ? xfs_inode_ag_walk.isra.13+0x2b5/0x620 [xfs] [ 1095.634582] ? xfs_inode_ag_walk.isra.13+0x91/0x620 [xfs] [ 1095.634618] ? xfs_inode_clear_eofblocks_tag+0x1a0/0x1a0 [xfs] [ 1095.634630] ? radix_tree_next_chunk+0x10b/0x2d0 [ 1095.634635] ? radix_tree_gang_lookup_tag+0xd7/0x150 [ 1095.634672] ? xfs_perag_get_tag+0x11d/0x370 [xfs] [ 1095.634690] ? xfs_perag_get_tag+0x5/0x370 [xfs] [ 1095.634709] ? xfs_inode_ag_iterator_tag+0x71/0xa0 [xfs] [ 1095.634726] ? xfs_inode_clear_eofblocks_tag+0x1a0/0x1a0 [xfs] [ 1095.634744] ? __xfs_icache_free_eofblocks+0x3b/0x40 [xfs] [ 1095.634759] ? xfs_eofblocks_worker+0x27/0x40 [xfs] [ 1095.634762] ? process_one_work+0x22b/0x760 [ 1095.634763] ? process_one_work+0x194/0x760 [ 1095.634784] ? rescuer_thread+0x1f2/0x3d0 [ 1095.634788] ? kthread+0x10f/0x150 [ 1095.634789] ? worker_thread+0x4b0/0x4b0 [ 1095.634790] ? kthread_create_on_node+0x70/0x70 [ 1095.634793] ? ret_from_fork+0x31/0x40 [ 1116.758199] Showing busy workqueues and worker pools: [ 1116.759630] workqueue events: flags=0x0 [ 1116.760882] pwq 6: cpus=3 node=0 flags=0x0 nice=0 active=5/256 [ 1116.762484] pending: vmpressure_work_fn, vmstat_shepherd, vmw_fb_dirty_flush [vmwgfx], check_corruption, console_callback [ 1116.765197] pwq 4: cpus=2 node=0 flags=0x0 nice=0 active=2/256 [ 1116.766841] pending: drain_local_pages_wq BAR(9595), e1000_watchdog [e1000] [ 1116.768755] pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=2/256 [ 1116.770778] in-flight: 7418:rht_deferred_worker [ 1116.772255] pending: rht_deferred_worker [ 1116.773648] workqueue events_long: flags=0x0 [ 1116.776610] pwq 6: cpus=3 node=0 flags=0x0 nice=0 active=1/256 [ 1116.778302] pending: gc_worker [nf_conntrack] [ 1116.779857] workqueue events_power_efficient: flags=0x80 [ 1116.781485] pwq 6: cpus=3 node=0 flags=0x0 nice=0 active=1/256 [ 1116.783175] pending: fb_flashcursor [ 1116.784452] pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=2/256 [ 1116.786265] pending: neigh_periodic_work, neigh_periodic_work [ 1116.788056] workqueue events_freezable_power_: flags=0x84 [ 1116.789748] pwq 4: cpus=2 node=0 flags=0x0 nice=0 active=1/256 [ 1116.791490] in-flight: 27:disk_events_workfn [ 1116.793092] workqueue writeback: flags=0x4e [ 1116.794471] pwq 256: cpus=0-127 flags=0x4 nice=0 active=2/256 [ 1116.796209] in-flight: 8444:wb_workfn wb_workfn [ 1116.798747] workqueue mpt_poll_0: flags=0x8 [ 1116.800223] pwq 4: cpus=2 node=0 flags=0x0 nice=0 active=1/256 [ 1116.801997] pending: mpt_fault_reset_work [mptbase] [ 1116.803780] workqueue xfs-data/sda1: flags=0xc [ 1116.805324] pwq 6: cpus=3 node=0 flags=0x0 nice=0 active=27/256 MAYDAY [ 1116.807272] in-flight: 5356:xfs_end_io [xfs], 451(RESCUER):xfs_end_io [xfs] xfs_end_io [xfs] xfs_end_io [xfs] xfs_end_io [xfs] xfs_end_io [xfs], 10498:xfs_end_io [xfs], 6386:xfs_end_io [xfs] [ 1116.812145] pending: xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs] [ 1116.820988] pwq 4: cpus=2 node=0 flags=0x0 nice=0 active=21/256 MAYDAY [ 1116.823105] in-flight: 535:xfs_end_io [xfs], 7416:xfs_end_io [xfs], 7415:xfs_end_io [xfs], 65:xfs_end_io [xfs] [ 1116.826062] pending: xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs], xfs_end_io [xfs] [ 1116.834549] pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=4/256 MAYDAY [ 1116.837139] in-flight: 5357:xfs_end_io [xfs], 193:xfs_end_io [xfs], 52:xfs_end_io [xfs], 5358:xfs_end_io [xfs] [ 1116.840182] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 [ 1116.842297] in-flight: 2486:xfs_end_io [xfs] [ 1116.844230] workqueue xfs-reclaim/sda1: flags=0xc [ 1116.846168] pwq 4: cpus=2 node=0 flags=0x0 nice=0 active=1/256 [ 1116.848323] pending: xfs_reclaim_worker [xfs] [ 1116.850280] workqueue xfs-eofblocks/sda1: flags=0xc [ 1116.852358] pwq 6: cpus=3 node=0 flags=0x0 nice=0 active=1/256 [ 1116.854601] in-flight: 456(RESCUER):xfs_eofblocks_worker [xfs] [ 1116.856826] pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=0s workers=3 idle: 3 6387 [ 1116.859293] pool 2: cpus=1 node=0 flags=0x0 nice=0 hung=670s workers=6 manager: 19 [ 1116.861762] pool 4: cpus=2 node=0 flags=0x0 nice=0 hung=673s workers=6 manager: 157 [ 1116.864240] pool 6: cpus=3 node=0 flags=0x0 nice=0 hung=673s workers=4 manager: 10499 [ 1116.866876] pool 256: cpus=0-127 flags=0x4 nice=0 hung=670s workers=3 idle: 425 426 ---------------------------------------- kthreadd (PID = 2) is trying to allocate "struct task_struct" requested by workqueue managers (PID = 19, 157, 10499) but is blocked on memory allocation. Since "struct task_struct" cannot be allocated for workqueues, RESCUER threads (PID = 451, 456) are responsible for making forward progress. ---------------------------------------- [ 1039.876146] kworker/1:0 D12872 19 2 0x00000000 [ 1039.877743] Call Trace: [ 1039.878717] __schedule+0x336/0xe00 [ 1039.879908] schedule+0x3d/0x90 [ 1039.881016] schedule_timeout+0x26a/0x510 [ 1039.882306] ? wait_for_completion_killable+0x56/0x1e0 [ 1039.883831] wait_for_completion_killable+0x166/0x1e0 [ 1039.885331] ? wake_up_q+0x80/0x80 [ 1039.886512] ? process_one_work+0x760/0x760 [ 1039.887827] __kthread_create_on_node+0x194/0x240 [ 1039.889255] kthread_create_on_node+0x49/0x70 [ 1039.890604] create_worker+0xca/0x1a0 [ 1039.891823] worker_thread+0x34d/0x4b0 [ 1039.893050] kthread+0x10f/0x150 [ 1039.894186] ? process_one_work+0x760/0x760 [ 1039.895518] ? kthread_create_on_node+0x70/0x70 [ 1039.896921] ret_from_fork+0x31/0x40 [ 1040.575900] kworker/2:2 D12504 157 2 0x00000000 [ 1040.577485] Call Trace: [ 1040.578469] __schedule+0x336/0xe00 [ 1040.579646] schedule+0x3d/0x90 [ 1040.580748] schedule_timeout+0x26a/0x510 [ 1040.582031] ? wait_for_completion_killable+0x56/0x1e0 [ 1040.583548] wait_for_completion_killable+0x166/0x1e0 [ 1040.585041] ? wake_up_q+0x80/0x80 [ 1040.586199] ? process_one_work+0x760/0x760 [ 1040.587859] __kthread_create_on_node+0x194/0x240 [ 1040.589294] kthread_create_on_node+0x49/0x70 [ 1040.590662] create_worker+0xca/0x1a0 [ 1040.591884] worker_thread+0x34d/0x4b0 [ 1040.593123] kthread+0x10f/0x150 [ 1040.594243] ? process_one_work+0x760/0x760 [ 1040.595572] ? kthread_create_on_node+0x70/0x70 [ 1040.596974] ret_from_fork+0x31/0x40 [ 1090.480342] kworker/3:1 D11280 10499 2 0x00000080 [ 1090.481966] Call Trace: [ 1090.482984] __schedule+0x336/0xe00 [ 1090.484228] ? account_entity_enqueue+0xdb/0x110 [ 1090.487424] schedule+0x3d/0x90 [ 1090.488575] schedule_timeout+0x26a/0x510 [ 1090.489881] ? wait_for_completion_killable+0x56/0x1e0 [ 1090.491615] wait_for_completion_killable+0x166/0x1e0 [ 1090.493143] ? wake_up_q+0x80/0x80 [ 1090.494334] ? process_one_work+0x760/0x760 [ 1090.495679] __kthread_create_on_node+0x194/0x240 [ 1090.498150] kthread_create_on_node+0x49/0x70 [ 1090.499518] create_worker+0xca/0x1a0 [ 1090.500737] worker_thread+0x34d/0x4b0 [ 1090.501986] kthread+0x10f/0x150 [ 1090.503126] ? process_one_work+0x760/0x760 [ 1090.504459] ? kthread_create_on_node+0x70/0x70 [ 1090.505857] ? do_syscall_64+0x195/0x200 [ 1090.507132] ret_from_fork+0x31/0x40 [ 1095.631379] MemAlloc: kthreadd(2) flags=0x208840 switches=313 seq=5 gfp=0x16040c0(GFP_KERNEL|__GFP_COMP|__GFP_NOTRACK) order=2 delay=652085 uninterruptible [ 1095.631380] kthreadd D11000 2 0 0x00000000 [ 1095.631384] Call Trace: [ 1095.631387] __schedule+0x336/0xe00 [ 1095.631388] ? __mutex_lock+0x1a2/0x9c0 [ 1095.631391] schedule+0x3d/0x90 [ 1095.631393] schedule_preempt_disabled+0x15/0x20 [ 1095.631394] __mutex_lock+0x2ed/0x9c0 [ 1095.631395] ? __mutex_lock+0xce/0x9c0 [ 1095.631397] ? radix_tree_gang_lookup_tag+0xd7/0x150 [ 1095.631417] ? xfs_reclaim_inodes_ag+0x3c6/0x4f0 [xfs] [ 1095.631439] ? xfs_perag_get_tag+0x5/0x370 [xfs] [ 1095.631441] mutex_lock_nested+0x1b/0x20 [ 1095.631473] xfs_reclaim_inodes_ag+0x3c6/0x4f0 [xfs] [ 1095.631500] ? xfs_reclaim_inodes_ag+0xf2/0x4f0 [xfs] [ 1095.631507] ? _raw_spin_unlock_irqrestore+0x3b/0x60 [ 1095.631510] ? try_to_wake_up+0x59/0x7a0 [ 1095.631514] ? wake_up_process+0x15/0x20 [ 1095.631557] xfs_reclaim_inodes_nr+0x33/0x40 [xfs] [ 1095.631580] xfs_fs_free_cached_objects+0x19/0x20 [xfs] [ 1095.631582] super_cache_scan+0x181/0x190 [ 1095.631585] shrink_slab+0x29f/0x6d0 [ 1095.631591] shrink_node+0x2fa/0x310 [ 1095.631594] do_try_to_free_pages+0xe1/0x300 [ 1095.631597] try_to_free_pages+0x131/0x3f0 [ 1095.631602] __alloc_pages_slowpath+0x3ec/0xd95 [ 1095.631606] ? _raw_spin_unlock+0x27/0x40 [ 1095.631610] __alloc_pages_nodemask+0x3e4/0x460 [ 1095.631611] ? cpumask_next_and+0x47/0xa0 [ 1095.631615] new_slab+0x450/0x6b0 [ 1095.631618] ___slab_alloc+0x3a3/0x620 [ 1095.631622] ? find_busiest_group+0x47/0x4d0 [ 1095.631624] ? copy_process.part.31+0x122/0x21e0 [ 1095.631627] ? copy_process.part.31+0x122/0x21e0 [ 1095.631629] __slab_alloc+0x46/0x7d [ 1095.631631] kmem_cache_alloc_node+0xab/0x3a0 [ 1095.631633] ? load_balance+0x1e7/0xb50 [ 1095.631635] copy_process.part.31+0x122/0x21e0 [ 1095.631638] ? pick_next_task_fair+0x6c6/0x890 [ 1095.631641] ? kthread_create_on_node+0x70/0x70 [ 1095.631642] ? finish_task_switch+0x70/0x240 [ 1095.631644] _do_fork+0xf3/0x750 [ 1095.631647] ? kthreadd+0x2f2/0x3c0 [ 1095.631650] kernel_thread+0x29/0x30 [ 1095.631651] kthreadd+0x35a/0x3c0 [ 1095.631652] ? ret_from_fork+0x31/0x40 [ 1095.631656] ? kthread_create_on_cpu+0xb0/0xb0 [ 1095.631658] ret_from_fork+0x31/0x40 ---------------------------------------- As usual, GFP_NOIO allocation by disk_events_workfn (as a crying canary indicating a lockup) is stalling there. ---------------------------------------- [ 1095.631687] MemAlloc: kworker/2:0(27) flags=0x4208860 switches=38727 seq=21 gfp=0x1400000(GFP_NOIO) order=0 delay=652160 [ 1095.631688] kworker/2:0 R running task 12680 27 2 0x00000000 [ 1095.631739] Workqueue: events_freezable_power_ disk_events_workfn [ 1095.631740] Call Trace: [ 1095.631743] __schedule+0x336/0xe00 [ 1095.631746] preempt_schedule_common+0x1f/0x31 [ 1095.631747] _cond_resched+0x1c/0x30 [ 1095.631749] shrink_slab+0x339/0x6d0 [ 1095.631754] shrink_node+0x2fa/0x310 [ 1095.631758] do_try_to_free_pages+0xe1/0x300 [ 1095.631761] try_to_free_pages+0x131/0x3f0 [ 1095.631765] __alloc_pages_slowpath+0x3ec/0xd95 [ 1095.631771] __alloc_pages_nodemask+0x3e4/0x460 [ 1095.631775] alloc_pages_current+0x97/0x1b0 [ 1095.631779] bio_copy_kern+0xc9/0x180 [ 1095.631830] blk_rq_map_kern+0x70/0x140 [ 1095.631835] __scsi_execute.isra.22+0x13a/0x1e0 [ 1095.631838] scsi_execute_req_flags+0x94/0x100 [ 1095.631844] sr_check_events+0xbf/0x2b0 [sr_mod] [ 1095.631852] cdrom_check_events+0x18/0x30 [cdrom] [ 1095.631854] sr_block_check_events+0x2a/0x30 [sr_mod] [ 1095.631856] disk_check_events+0x60/0x170 [ 1095.631859] disk_events_workfn+0x1c/0x20 [ 1095.631862] process_one_work+0x22b/0x760 [ 1095.631863] ? process_one_work+0x194/0x760 [ 1095.631867] worker_thread+0x137/0x4b0 [ 1095.631887] kthread+0x10f/0x150 [ 1095.631889] ? process_one_work+0x760/0x760 [ 1095.631890] ? kthread_create_on_node+0x70/0x70 [ 1095.631893] ret_from_fork+0x31/0x40 ---------------------------------------- Due to __GFP_NOWARN, warn_alloc() cannot warn allocation stalls. Due to order <= PAGE_ALLOC_COSTLY_ORDER without __GFP_NORETRY, the "%s(%u) possible memory allocation deadlock size %u in %s (mode:0x%x)" message cannot be printed because __alloc_pages_nodemask() does not return. And due to GFP_NOFS with neither __GFP_HIGH nor __GFP_NOFAIL, memory cannot be allocated to RESCUER threads which are trying to allocate memory for reclaiming memory. Setting PF_MEMALLOC will disable direct reclaim and allow access to memory reserves, but allocation failure is not acceptable due to !KM_MAYFAIL. Passing __GFP_HIGH and/or __GFP_NOFAIL will allow access to memory reserves, but allocation might still loop forever inside the page allocator (especially if order > 0) because commit 06ad276ac18742c6 ("mm, oom: do not enforce OOM killer for __GFP_NOFAIL automatically") deprived WQ_MEM_RECLAIM users of the last resort for invoking the OOM killer. If order > 0 allocation request with __GFP_NOFAIL fails due to fragmentation, there is nothing we can do. Passing __GFP_NORETRY will allow the "%s(%u) possible memory allocation deadlock size %u in %s (mode:0x%x)" message to be printed but that helps only emitting warning. So, how can we avoid this situation? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
