From 94cc81f9a8f995923e35e2db936741dd62d18350 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Wed, 10 Jun 2015 17:49:40 +0200 Subject: swiotlb: Warn on allocation failure in swiotlb_alloc_coherent() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Print a warning when all allocation tries have been failed and the function is about to return NULL. This prepares for calling the function with __GFP_NOWARN to suppress allocation failure warnings before all fall-backs have failed - which we'll do to improve kdump behavior. Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Acked-by: Konrad Rzeszutek Wilk Acked-by: Baoquan He Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Young Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Jörg Rödel Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vivek Goyal Cc: kexec@lists.infradead.org Link: http://lkml.kernel.org/r/1433500202-25531-2-git-send-email-joro@8bytes.org Signed-off-by: Ingo Molnar diff --git a/lib/swiotlb.c b/lib/swiotlb.c index 3c365ab..42e192d 100644 --- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -656,7 +656,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size, */ phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE); if (paddr == SWIOTLB_MAP_ERROR) - return NULL; + goto err_warn; ret = phys_to_virt(paddr); dev_addr = phys_to_dma(hwdev, paddr); @@ -670,7 +670,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size, /* DMA_TO_DEVICE to avoid memcpy in unmap_single */ swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE); - return NULL; + goto err_warn; } } @@ -678,6 +678,13 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size, memset(ret, 0, size); return ret; + +err_warn: + pr_warn("swiotlb: coherent allocation failed for device %s size=%zu\n", + dev_name(hwdev), size); + dump_stack(); + + return NULL; } EXPORT_SYMBOL(swiotlb_alloc_coherent); -- cgit v0.10.2 From 186dfc9d69b96a38ec6ec654127dba4432184494 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Wed, 10 Jun 2015 17:49:41 +0200 Subject: x86/swiotlb: Try coherent allocations with __GFP_NOWARN MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 fall-back 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 [ Simplify, reflow comment. ] Signed-off-by: Borislav Petkov Acked-by: Baoquan He Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Young Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Jörg Rödel Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vivek Goyal Cc: kexec@lists.infradead.org Link: http://lkml.kernel.org/r/1433500202-25531-3-git-send-email-joro@8bytes.org Signed-off-by: Ingo Molnar diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c index 77dd0ad..adf0392 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) -- cgit v0.10.2 From 94fb9334182284e8e7e4bcb9125c25dc33af19d4 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Wed, 10 Jun 2015 17:49:42 +0200 Subject: x86/crash: Allocate enough low memory when crashkernel=high MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When the crash kernel is loaded above 4GiB in memory, the first kernel allocates only 72MiB of low-memory for the DMA requirements of the second kernel. On systems with many devices this is not enough and causes device driver initialization errors and failed crash dumps. Testing by SUSE and Redhat has shown that 256MiB is a good default value for now and the discussion has lead to this value as well. So set this default value to 256MiB to make sure there is enough memory available for DMA. Signed-off-by: Joerg Roedel [ Reflow comment. ] Signed-off-by: Borislav Petkov Acked-by: Baoquan He Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Young Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Jörg Rödel Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vivek Goyal Cc: kexec@lists.infradead.org Link: http://lkml.kernel.org/r/1433500202-25531-4-git-send-email-joro@8bytes.org Signed-off-by: Ingo Molnar diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index d74ac33..cba8288 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -531,12 +531,14 @@ static void __init reserve_crashkernel_low(void) if (ret != 0) { /* * two parts from lib/swiotlb.c: - * swiotlb size: user specified with swiotlb= or default. - * swiotlb overflow buffer: now is hardcoded to 32k. - * We round it to 8M for other buffers that - * may need to stay low too. + * -swiotlb size: user-specified with swiotlb= or default. + * + * -swiotlb overflow buffer: now hardcoded to 32k. We round it + * to 8M for other buffers that may need to stay low too. Also + * make sure we allocate enough extra low memory so that we + * don't run out of DMA buffers for 32-bit devices. */ - low_size = swiotlb_size_or_default() + (8UL<<20); + low_size = max(swiotlb_size_or_default() + (8UL<<20), 256UL<<20); auto_set = true; } else { /* passed with crashkernel=0,low ? */ -- cgit v0.10.2