From: Joerg Roedel <[email protected]> When we boot a kdump kernel in high memory, there is by default only 72MB of low memory available. The swiotlb code takes 64MB of it (by default) so that there are only 8MB left to allocate from. On systems with many devices this causes page allocator warnings from dma_generic_alloc_coherent():
systemd-udevd: page allocation failure: order:0, mode:0x280d4 CPU: 0 PID: 197 Comm: systemd-udevd Tainted: G W 3.12.28-4-default #1 Hardware name: HP ProLiant DL980 G7, BIOS P66 07/30/2012 ffff8800781335e0 ffffffff8150b1db 00000000000280d4 ffffffff8113af90 0000000000000000 0000000000000000 ffff88007efdbb00 0000000100000000 0000000000000000 0000000000000000 0000000000000000 0000000000000001 Call Trace: dump_trace+0x7d/0x2d0 show_stack_log_lvl+0x94/0x170 show_stack+0x21/0x50 dump_stack+0x41/0x51 warn_alloc_failed+0xf0/0x160 __alloc_pages_slowpath+0x72f/0x796 __alloc_pages_nodemask+0x1ea/0x210 dma_generic_alloc_coherent+0x96/0x140 x86_swiotlb_alloc_coherent+0x1c/0x50 ttm_dma_pool_alloc_new_pages+0xab/0x320 [ttm] ttm_dma_populate+0x3ce/0x640 [ttm] ttm_tt_bind+0x36/0x60 [ttm] ttm_bo_handle_move_mem+0x55f/0x5c0 [ttm] ttm_bo_move_buffer+0x105/0x130 [ttm] ttm_bo_validate+0xc1/0x130 [ttm] ttm_bo_init+0x24b/0x400 [ttm] radeon_bo_create+0x16c/0x200 [radeon] radeon_ring_init+0x11e/0x2b0 [radeon] r100_cp_init+0x123/0x5b0 [radeon] r100_startup+0x194/0x230 [radeon] r100_init+0x223/0x410 [radeon] radeon_device_init+0x6af/0x830 [radeon] radeon_driver_load_kms+0x89/0x180 [radeon] drm_get_pci_dev+0x121/0x2f0 [drm] local_pci_probe+0x39/0x60 pci_device_probe+0xa9/0x120 driver_probe_device+0x9d/0x3d0 __driver_attach+0x8b/0x90 bus_for_each_dev+0x5b/0x90 bus_add_driver+0x1f8/0x2c0 driver_register+0x5b/0xe0 do_one_initcall+0xf2/0x1a0 load_module+0x1207/0x1c70 SYSC_finit_module+0x75/0xa0 system_call_fastpath+0x16/0x1b 0x7fac533d2788 After these warnings the code enters a fallback path and allocated directly from the swiotlb aperture in the end. So remove these warnings as this is not a fatal error. Signed-off-by: Joerg Roedel <[email protected]> Acked-by: Baoquan He <[email protected]> Cc: Baoquan He <[email protected]> Cc: Dave Young <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Jörg Rödel <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Vivek Goyal <[email protected]> Cc: [email protected] Cc: x86-ml <[email protected]> Link: http://lkml.kernel.org/r/[email protected] [ Simplify, reflow comment. ] Signed-off-by: Borislav Petkov <[email protected]> --- arch/x86/kernel/pci-swiotlb.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c index 77dd0ad58be4..adf0392d549a 100644 --- a/arch/x86/kernel/pci-swiotlb.c +++ b/arch/x86/kernel/pci-swiotlb.c @@ -20,6 +20,13 @@ void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size, { void *vaddr; + /* + * Don't print a warning when the first allocation attempt fails. + * swiotlb_alloc_coherent() will print a warning when the DMA + * memory allocation ultimately failed. + */ + flags |= __GFP_NOWARN; + vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags, attrs); if (vaddr) -- 2.3.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
