On 17/08/2023 17:19, Suzuki K Poulose wrote:
Running the following command on Juno triggers the warning:
$ perf record -e cs_etm// -m ,128M ...
------------[ cut here ]------------ WARNING: CPU: 1 PID: 412 at mm/page_alloc.c:4453 __alloc_pages+0x334/0x1420 CPU: 1 PID: 412 Comm: perf Not tainted 6.5.0-rc3+ #181 Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Feb 1 2019 pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __alloc_pages+0x334/0x1420 lr : dma_common_alloc_pages+0x108/0x138 sp : ffffffc087fb7440 x29: ffffffc087fb7440 x28: 0000000000000000 x27: ffffffc07e48fba0 x26: 0000000000000001 x25: 000000000000000f x24: ffffffc081f24880 x23: 0000000000000cc0 x22: ffffff88012b6f08 x21: 0000000008000000 x20: ffffff8801433000 x19: 0000000000000000 x18: 0000000000000000 x17: ffffffc080316e5c x16: ffffffc07e46406c x15: ffffffc0803af580 x14: ffffffc08036b460 x13: ffffffc080025cbc x12: ffffffb8108c3fc4 x11: 1ffffff8108c3fc3 x10: 1ffffff810ff6eac x9 : 00000000f204f204 x8 : 000000000000f204 x7 : 00000000f2f2f2f2 x6 : 00000000f3f3f3f3 x5 : 0000000000000001 x4 : 0000000000000000 x3 : 0000000000000000 x2 : 0000000000000cc0 x1 : 0000000000000000 x0 : ffffffc085333000 Call trace: __alloc_pages+0x334/0x1420 dma_common_alloc_pages+0x108/0x138 __dma_alloc_pages+0xf4/0x108 dma_alloc_pages+0x18/0x30 tmc_etr_alloc_flat_buf+0xa0/0x190 [coresight_tmc] tmc_alloc_etr_buf.constprop.0+0x124/0x298 [coresight_tmc] alloc_etr_buf.constprop.0.isra.0+0x88/0xc8 [coresight_tmc] tmc_alloc_etr_buffer+0x164/0x2f0 [coresight_tmc] etm_setup_aux+0x32c/0x520 [coresight] rb_alloc_aux+0x29c/0x3f8 perf_mmap+0x59c/0xce0 mmap_region+0x340/0x10e0 do_mmap+0x48c/0x580 vm_mmap_pgoff+0x160/0x248 ksys_mmap_pgoff+0x1e8/0x278 __arm64_sys_mmap+0x8c/0xb8
With the flat mode, we only attempt to allocate large memory if there is an IOMMU connected to the ETR. If the allocation fails, we always have a fallback path and return an error if nothing else worked. So, suppress the warning for flat mode allocations.
Cc: Mike Leach mike.leach@linaro.org Cc: James Clark james.clark@arm.com Cc: Anshuman Khandual anshuman.khandual@arm.com Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com
Reviewed-by: James Clark james.clark@arm.com
drivers/hwtracing/coresight/coresight-tmc-etr.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 66dc5f97a009..c8df8719f6a0 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -610,7 +610,8 @@ static int tmc_etr_alloc_flat_buf(struct tmc_drvdata *drvdata, flat_buf->vaddr = dma_alloc_noncoherent(real_dev, etr_buf->size, &flat_buf->daddr,
DMA_FROM_DEVICE, GFP_KERNEL);
DMA_FROM_DEVICE,GFP_KERNEL | __GFP_NOWARN);