| Message ID | 20210810094835.13402-6-bhe@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Avoid requesting page from DMA zone when no managed pages | expand |
diff --git a/mm/slab_common.c b/mm/slab_common.c index 1c673c323baf..22350bef3bae 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -911,10 +911,16 @@ void __init create_kmalloc_caches(slab_flags_t flags) slab_state = UP; #ifdef CONFIG_ZONE_DMA + bool managed_dma = has_managed_dma(); + for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) { struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i]; if (s) { + if (!managed_dma) { + kmalloc_caches[KMALLOC_DMA][i] = kmalloc_caches[KMALLOC_NORMAL][i]; + continue; + } kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache( kmalloc_info[i].name[KMALLOC_DMA], kmalloc_info[i].size,
Dma-kmalloc will be created as long as CONFIG_ZONE_DMA is enabled. However, it will fail if DMA zone has no managed pages. The failure can be seen in kdump kernel of x86_64 as below: CPU: 0 PID: 65 Comm: kworker/u2:1 Not tainted 5.14.0-rc2+ #9 Hardware name: Intel Corporation SandyBridge Platform/To be filled by O.E.M., BIOS RMLSDP.86I.R2.28.D690.1306271008 06/27/2013 Workqueue: events_unbound async_run_entry_fn Call Trace: dump_stack_lvl+0x57/0x72 warn_alloc.cold+0x72/0xd6 __alloc_pages_slowpath.constprop.0+0xf56/0xf70 __alloc_pages+0x23b/0x2b0 allocate_slab+0x406/0x630 ___slab_alloc+0x4b1/0x7e0 ? sr_probe+0x200/0x600 ? lock_acquire+0xc4/0x2e0 ? fs_reclaim_acquire+0x4d/0xe0 ? lock_is_held_type+0xa7/0x120 ? sr_probe+0x200/0x600 ? __slab_alloc+0x67/0x90 __slab_alloc+0x67/0x90 ? sr_probe+0x200/0x600 ? sr_probe+0x200/0x600 kmem_cache_alloc_trace+0x259/0x270 sr_probe+0x200/0x600 ...... bus_probe_device+0x9f/0xb0 device_add+0x3d2/0x970 ...... __scsi_add_device+0xea/0x100 ata_scsi_scan_host+0x97/0x1d0 async_run_entry_fn+0x30/0x130 process_one_work+0x2b0/0x5c0 worker_thread+0x55/0x3c0 ? process_one_work+0x5c0/0x5c0 kthread+0x149/0x170 ? set_kthread_struct+0x40/0x40 ret_from_fork+0x22/0x30 Mem-Info: ...... The above failure happened when calling kmalloc() to allocate buffer with GFP_DMA. It requests to allocate slab page from DMA zone while no managed pages in there. sr_probe() --> get_capabilities() --> buffer = kmalloc(512, GFP_KERNEL | GFP_DMA); The DMA zone should be checked if it has managed pages, then try to create dma-kmalloc. Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vlastimil Babka <vbabka@suse.cz> --- mm/slab_common.c | 6 ++++++ 1 file changed, 6 insertions(+)