On 29.06.2016 16:22, StDenis, Tom wrote: > Thanks. I use vmalloc first to avoid putting the array on the stack (as > good practice) then I chose vmalloc because there really isn't a need > for contiguous memory and in theory it should be just as fast to > allocate. Wouldn't you typically use kmalloc when you need contiguous > memory? Though this all boils down to a single page since it's so small > anyways. If it's potentially non-contiguous memory, isn't there the overhead of page table manipulation? Maybe somebody who's more familiar with the kernel has an opinion... Cheers, Nicolai > > > Tom > > > > > > ------------------------------------------------------------------------ > *From:* Nicolai Hähnle <nhaehnle at gmail.com> > *Sent:* Wednesday, June 29, 2016 10:20 > *To:* Tom St Denis; amd-gfx at lists.freedesktop.org > *Cc:* StDenis, Tom > *Subject:* Re: [PATCH 3/3] drm/amd/amdgpu: Add bank selection for MMIO > debugfs (v3) > Patch 1 & 3 are > > Reviewed-by: Nicolai Hähnle <nicolai.haehnle at amd.com> > > Patch 2 looks mostly fine to me, too, but I'm not sure about the > vmalloc/vfree vs. kmalloc/kfree. > > Cheers, > Nicolai > > On 29.06.2016 15:56, Tom St Denis wrote: >> (v2) Added INSTANCE selector >> (v3) Changed order of bank selectors >> >> Signed-off-by: Tom St Denis <tom.stdenis at amd.com> >> --- >> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 35 +++++++++++++++++++++++++++--- >> 1 file changed, 32 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c >> index 7f08ac02f9de..4a8f66c5ff43 100644 >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c >> @@ -2244,20 +2244,43 @@ static ssize_t amdgpu_debugfs_regs_read(struct file *f, char __user *buf, >> struct amdgpu_device *adev = f->f_inode->i_private; >> ssize_t result = 0; >> int r; >> + bool use_bank; >> + unsigned instance_bank, sh_bank, se_bank; >> >> if (size & 0x3 || *pos & 0x3) >> return -EINVAL; >> >> + if (*pos & (1ULL << 62)) { >> + se_bank = (*pos >> 24) & 0x3FF; >> + sh_bank = (*pos >> 34) & 0x3FF; >> + instance_bank = (*pos >> 44) & 0x3FF; >> + use_bank = 1; >> + *pos &= 0xFFFFFF; >> + } else { >> + use_bank = 0; >> + } >> + >> + if (use_bank) { >> + if (sh_bank >= adev->gfx.config.max_sh_per_se || >> + se_bank >= adev->gfx.config.max_shader_engines) >> + return -EINVAL; >> + mutex_lock(&adev->grbm_idx_mutex); >> + amdgpu_gfx_select_se_sh(adev, se_bank, >> + sh_bank, instance_bank); >> + } >> + >> while (size) { >> uint32_t value; >> >> if (*pos > adev->rmmio_size) >> - return result; >> + goto end; >> >> value = RREG32(*pos >> 2); >> r = put_user(value, (uint32_t *)buf); >> - if (r) >> - return r; >> + if (r) { >> + result = r; >> + goto end; >> + } >> >> result += 4; >> buf += 4; >> @@ -2265,6 +2288,12 @@ static ssize_t amdgpu_debugfs_regs_read(struct file *f, char __user *buf, >> size -= 4; >> } >> >> +end: >> + if (use_bank) { >> + amdgpu_gfx_select_se_sh(adev, 0xffffffff, 0xffffffff, 0xffffffff); >> + mutex_unlock(&adev->grbm_idx_mutex); >> + } >> + >> return result; >> } >> >>