Re: Backporting "silence nfscache allocation warnings with kvzalloc" - 8c38b705b4f4ca4e7f9cc116141bc38391917c30 into 5.4-stable and potentially older stable kernels?

[Greg KH <greg@kroah.com>]

On Wed, Oct 06, 2021 at 09:20:29AM -0700, Krzysztof Olędzki wrote:
> (re-sent with the proper stable@ address)
> 
> On 2021-06-10 at 16:37, Krzysztof Olędzki wrote:
> > Hi,
> > 
> > I noticed sporadic "page allocation failure" errors in my systems
> > running 5.4-stable kernels, that look like this:
> > 
> > [1530107.418557] emerge: page allocation failure: order:5, mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), nodemask=(null),cpuset=/,mems_allowed=0
> > [1530107.418575] CPU: 7 PID: 673 Comm: emerge Not tainted 5.4.121-o3 #1
> > [1530107.418576] Hardware name: Dell Inc. PowerEdge T110 II/0PM2CW, BIOS 2.10.0 05/24/2018
> > [1530107.418577] Call Trace:
> > [1530107.418585]  dump_stack+0x50/0x63
> > [1530107.418589]  warn_alloc+0xde/0x15c
> > [1530107.418591]  __alloc_pages_slowpath+0x759/0x786
> > [1530107.418594]  ? kernfs_add_one+0xf6/0x10d
> > [1530107.418597]  ? preempt_latency_start+0x2b/0x3e
> > [1530107.418600]  ? ida_alloc_range+0x2bc/0x378
> > [1530107.418602]  __alloc_pages_nodemask+0x17d/0x243
> > [1530107.418605]  kmalloc_order+0x1b/0x69
> > [1530107.418607]  kmalloc_order_trace+0x18/0xa1
> > [1530107.418609]  nfsd_reply_cache_init+0xae/0x13a
> > [1530107.418612]  nfsd_init_net+0x66/0xfe
> > [1530107.418615]  ops_init+0xa9/0xd5
> > [1530107.418617]  setup_net+0xb3/0x19b
> > [1530107.418619]  copy_net_ns+0xec/0x140
> > [1530107.418621]  create_new_namespaces+0x125/0x19a
> > [1530107.418623]  unshare_nsproxy_namespaces+0x86/0x9c
> > [1530107.418626]  ksys_unshare+0x14b/0x2e3
> > [1530107.418628]  __x64_sys_unshare+0x9/0xc
> > [1530107.418630]  do_syscall_64+0x72/0x7f
> > [1530107.418633]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > [1530107.418636] RIP: 0033:0x7f47d7161f97
> > [1530107.418638] Code: 73 01 c3 48 8b 0d d1 fe 0b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 10 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 fe 0b 00 f7 d8 64 89 01 48
> > [1530107.418639] RSP: 002b:00007ffd9a1f61f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
> > [1530107.418641] RAX: ffffffffffffffda RBX: 00007ffd9a1f6200 RCX: 00007f47d7161f97
> > [1530107.418642] RDX: 0000000000000000 RSI: 00007f47c95d2800 RDI: 000000006c020000
> > [1530107.418643] RBP: 00007ffd9a1f6200 R08: 0000000000000000 R09: 00007ffd9a1f6250
> > [1530107.418643] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd9a1f6348
> > [1530107.418644] R13: 0000000000000000 R14: 00007ffd9a1f62c0 R15: 00007ffd9a1f6328
> > [1530107.418646] Mem-Info:
> > [1530107.418650] active_anon:507099 inactive_anon:153606 isolated_anon:0
> >                    active_file:2413575 inactive_file:4701878 isolated_file:0
> >                    unevictable:2557 dirty:2354 writeback:0 unstable:0
> >                    slab_reclaimable:275977 slab_unreclaimable:23789
> >                    mapped:27516 shmem:12726 pagetables:5087 bounce:0
> >                    free:83786 free_pcp:0 free_cma:0
> > [1530107.418653] Node 0 active_anon:2028396kB inactive_anon:614424kB active_file:9654300kB inactive_file:18807512kB unevictable:10228kB isolated(anon):0kB isolated(file):0kB mapped:110064kB dirty:9416kB writeback:0kB shmem:50904kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no
> > [1530107.418656] DMA free:15888kB min:8kB low:20kB high:32kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15988kB managed:15904kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> > [1530107.418657] lowmem_reserve[]: 0 2422 32068 32068
> > [1530107.418661] DMA32 free:248688kB min:1728kB low:4208kB high:6688kB active_anon:94588kB inactive_anon:108056kB active_file:976696kB inactive_file:792500kB unevictable:104kB writepending:2744kB present:2574428kB managed:2549240kB mlocked:104kB kernel_stack:192kB pagetables:968kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> > [1530107.418662] lowmem_reserve[]: 0 0 29645 29645
> > [1530107.418666] Normal free:70568kB min:21180kB low:51536kB high:81892kB active_anon:1934340kB inactive_anon:506132kB active_file:8677844kB inactive_file:18015144kB unevictable:10124kB writepending:6672kB present:30932992kB managed:30357820kB mlocked:10124kB kernel_stack:5732kB pagetables:19380kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> > [1530107.418666] lowmem_reserve[]: 0 0 0 0
> > [1530107.418668] DMA: 0*4kB 0*8kB 1*16kB (U) 0*32kB 2*64kB (U) 1*128kB (U) 1*256kB (U) 0*512kB 1*1024kB (U) 1*2048kB (M) 3*4096kB (M) = 15888kB
> > [1530107.418674] DMA32: 10702*4kB (UME) 3914*8kB (UME) 4900*16kB (UME) 1794*32kB (UME) 623*64kB (UM) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 249800kB
> > [1530107.418680] Normal: 1795*4kB (UMEH) 635*8kB (UMEH) 284*16kB (UMH) 297*32kB (UMEH) 703*64kB (MEH) 3*128kB (H) 0*256kB 1*512kB (H) 0*1024kB 0*2048kB 0*4096kB = 72196kB
> > [1530107.418687] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
> > [1530107.418688] 7129905 total pagecache pages
> > [1530107.418690] 13 pages in swap cache
> > [1530107.418691] Swap cache stats: add 121, delete 108, find 15/20
> > [1530107.418692] Free swap  = 4191732kB
> > [1530107.418692] Total swap = 4193276kB
> > [1530107.418693] 8380852 pages RAM
> > [1530107.418694] 0 pages HighMem/MovableOnly
> > [1530107.418694] 150111 pages reserved
> > 
> > If I'm not mistaken, 5.10 and newer kernels have a fix for this:
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8c38b705b4f4ca4e7f9cc116141bc38391917c30
> > 
> > I wonder if it would be possible to include it in 5.4-stable and potentially older stable kernels?

I've applied this to the 5.4.y tree, but it did not apply to older
kernels.  If you want it on them, please provide a working backport.

thanks,

greg k-h