Hi Chen, On Thu, May 21, 2020 at 3:05 PM Chen Zhou <chenzhou10@xxxxxxxxxx> wrote: > > This patch series enable reserving crashkernel above 4G in arm64. > > There are following issues in arm64 kdump: > 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail > when there is no enough low memory. > 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G, > in this case, if swiotlb or DMA buffers are required, crash dump kernel > will boot failure because there is no low memory available for allocation. > > To solve these issues, introduce crashkernel=X,low to reserve specified > size low memory. > Crashkernel=X tries to reserve memory for the crash dump kernel under > 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified > size low memory for crash kdump kernel devices firstly and then reserve > memory above 4G. > > When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low > is specified simultaneously, kernel should reserve specified size low memory > for crash dump kernel devices. So there may be two crash kernel regions, one > is below 4G, the other is above 4G. > In order to distinct from the high region and make no effect to the use of > kexec-tools, rename the low region as "Crash kernel (low)", and add DT property > "linux,low-memory-range" to crash dump kernel's dtb to pass the low region. > > Besides, we need to modify kexec-tools: > arm64: kdump: add another DT property to crash dump kernel's dtb(see [1]) > > The previous changes and discussions can be retrieved from: > > Changes since [v7] > - Move x86 CRASH_ALIGN to 2M > Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M. > - Update Documentation/devicetree/bindings/chosen.txt > Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd. > - Add Tested-by from Jhon and pk > > Changes since [v6] > - Fix build errors reported by kbuild test robot. > > Changes since [v5] > - Move reserve_crashkernel_low() into kernel/crash_core.c. > - Delete crashkernel=X,high. > - Modify crashkernel=X,low. > If crashkernel=X,low is specified simultaneously, reserve spcified size low > memory for crash kdump kernel devices firstly and then reserve memory above 4G. > In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then > pass to crash dump kernel by DT property "linux,low-memory-range". > - Update Documentation/admin-guide/kdump/kdump.rst. > > Changes since [v4] > - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike. > > Changes since [v3] > - Add memblock_cap_memory_ranges back for multiple ranges. > - Fix some compiling warnings. > > Changes since [v2] > - Split patch "arm64: kdump: support reserving crashkernel above 4G" as > two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate > patch. > > Changes since [v1]: > - Move common reserve_crashkernel_low() code into kernel/kexec_core.c. > - Remove memblock_cap_memory_ranges() i added in v1 and implement that > in fdt_enforce_memory_region(). > There are at most two crash kernel regions, for two crash kernel regions > case, we cap the memory range [min(regs[*].start), max(regs[*].end)] > and then remove the memory range in the middle. > > [1]: http://lists.infradead.org/pipermail/kexec/2020-May/025128.html > [v1]: https://lkml.org/lkml/2019/4/2/1174 > [v2]: https://lkml.org/lkml/2019/4/9/86 > [v3]: https://lkml.org/lkml/2019/4/9/306 > [v4]: https://lkml.org/lkml/2019/4/15/273 > [v5]: https://lkml.org/lkml/2019/5/6/1360 > [v6]: https://lkml.org/lkml/2019/8/30/142 > [v7]: https://lkml.org/lkml/2019/12/23/411 > > Chen Zhou (5): > x86: kdump: move reserve_crashkernel_low() into crash_core.c > arm64: kdump: reserve crashkenel above 4G for crash dump kernel > arm64: kdump: add memory for devices by DT property, low-memory-range > kdump: update Documentation about crashkernel on arm64 > dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump > We are getting "warn_alloc" [1] warning during boot of kdump kernel with bootargs as [2] of primary kernel. This error observed on ThunderX2 ARM64 platform. It is observed with latest upstream tag (v5.7-rc3) with this patch set and https://lists.infradead.org/pipermail/kexec/2020-May/025128.html Also **without** this patch-set "https://www.spinics.net/lists/arm-kernel/msg806882.html"; This issue comes whenever crashkernel memory is reserved after 0xc000_0000. More details discussed earlier in https://www.spinics.net/lists/arm-kernel/msg806882.html without any solution This patch-set is expected to solve similar kind of issue. i.e. low memory is only targeted for DMA, swiotlb; So above mentioned observation should be considered/fixed. . --pk [1] [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy [ 30.367696] NET: Registered protocol family 16 [ 30.369973] swapper/0: page allocation failure: order:6, mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0 [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc3+ #121 [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy [ 30.369984] Call trace: [ 30.369989] dump_backtrace+0x0/0x1f8 [ 30.369991] show_stack+0x20/0x30 [ 30.369997] dump_stack+0xc0/0x10c [ 30.370001] warn_alloc+0x10c/0x178 [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0xb50 [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300 [ 30.370008] alloc_page_interleave+0x24/0x98 [ 30.370011] alloc_pages_current+0xe4/0x108 [ 30.370017] dma_atomic_pool_init+0x44/0x1a4 [ 30.370020] do_one_initcall+0x54/0x228 [ 30.370027] kernel_init_freeable+0x228/0x2cc [ 30.370031] kernel_init+0x1c/0x110 [ 30.370034] ret_from_fork+0x10/0x18 [ 30.370036] Mem-Info: [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0 [ 30.370064] active_file:0 inactive_file:0 isolated_file:0 [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0 [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438 [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0 [ 30.370064] free:1537719 free_pcp:219 free_cma:0 [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:128kB managed:0kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB [ 30.370084] lowmem_reserve[]: 0 250 6063 6063 [ 30.370090] Node 0 DMA32 free:256000kB min:408kB low:664kB high:920kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:269700kB managed:256000kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB [ 30.370094] lowmem_reserve[]: 0 0 5813 5813 [ 30.370100] Node 0 Normal free:5894876kB min:9552kB low:15504kB high:21456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:8388608kB managed:5953112kB mlocked:0kB kernel_stack:21672kB pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB free_cma:0kB [ 30.370104] lowmem_reserve[]: 0 0 0 0 [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) = 256000kB [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB (UE) 3*32kB (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME) 3*1024kB (ME) 3*2048kB (UME) 1436*4096kB (M) = 5893600kB [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB [ 30.370130] 0 total pagecache pages [ 30.370132] 0 pages in swap cache [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0 [ 30.370135] Free swap = 0kB [ 30.370136] Total swap = 0kB [ 30.370137] 2164609 pages RAM [ 30.370139] 0 pages HighMem/MovableOnly [ 30.370140] 612331 pages reserved [ 30.370141] 0 pages hwpoisoned [ 30.370143] DMA: failed to allocate 256 KiB pool for atomic coherent allocation [2] root@localhost$ dmesg | grep crash [ 0.000000] Reserving 250MB of low memory at 3724MB for crashkernel (System low RAM: 2029MB) [ 0.000000] crashkernel reserved: 0x0000000e00000000 - 0x0000001000000000 (8192 MB) [ 0.000000] Kernel command line: BOOT_IMAGE=(hd11,gpt2)/vmlinuz-5.7.0-rc3+ root=UUID=e5c34f86-6727-4668-81f9-f41433555df6 ro crashkernel=250M,low crashkernel=8G nowatchdog console=ttyAMA0 default_hugepagesz=1G hugepagesz=1G hugepages=2 [ 44.019393] crashkernel=8G _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
