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[AMD Official Use Only - AMD Internal Distribution Only]<br>
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<p class="MsoNormal"><span style="font-size:11.0pt">The change of granularity from 0x3F to 0x1B is based on review comments from Felix<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;color:black">Regards,</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:black">Ramesh</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;color:black"> </span><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Yang, Philip <Philip.Yang@amd.com>
<br>
<b>Sent:</b> Tuesday, September 3, 2024 11:36 AM<br>
<b>To:</b> Chen, Xiaogang <Xiaogang.Chen@amd.com>; Errabolu, Ramesh <Ramesh.Errabolu@amd.com>; amd-gfx@lists.freedesktop.org<br>
<b>Subject:</b> Re: [PATCH V3] drm/amdgpu: Surface svm_default_granularity, a RW module parameter<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p><o:p> </o:p></p>
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<p class="MsoNormal">On 2024-08-29 18:31, Chen, Xiaogang wrote:<o:p></o:p></p>
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<br>
On 8/29/2024 5:13 PM, Ramesh Errabolu wrote: <br>
<br>
<o:p></o:p></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal">Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
<br>
<br>
<br>
Enables users to update SVM's default granularity, used in <br>
buffer migration and handling of recoverable page faults. <br>
Param value is set in terms of log(numPages(buffer)), <br>
e.g. 9 for a 2 MIB buffer <o:p></o:p></p>
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<p class="MsoNormal"><br>
Forgot asking if this parameter is request from customer or used for debug/experiment purpose? If it is later, how about put it at debug fs? There are already many driver parameters.
<o:p></o:p></p>
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<p>debugfs is not always available, depending on kernel configuration, and debugfs seems for debugging purpose, ex. /sys/kernel/debug/kfd/mqds, hqds, not for functional purpose. one comment embedded below.<o:p></o:p></p>
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<p class="MsoNormal"><br>
Regards <br>
<br>
Xiaogang <br>
<br>
<br>
<o:p></o:p></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal">Signed-off-by: Ramesh Errabolu <a href="mailto:Ramesh.Errabolu@amd.com">
<Ramesh.Errabolu@amd.com></a> <br>
--- <br>
drivers/gpu/drm/amd/amdgpu/amdgpu.h | 1 + <br>
drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 17 +++++++++++++++++ <br>
drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 6 ++++++ <br>
drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 25 +++++++++++++++---------- <br>
4 files changed, 39 insertions(+), 10 deletions(-) <br>
<br>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
<br>
index e8c284aea1f2..8eb934af02f2 100644 <br>
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h <br>
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h <br>
@@ -237,6 +237,7 @@ extern int sched_policy; <br>
extern bool debug_evictions; <br>
extern bool no_system_mem_limit; <br>
extern int halt_if_hws_hang; <br>
+extern uint amdgpu_svm_default_granularity; <br>
#else <br>
static const int __maybe_unused sched_policy = KFD_SCHED_POLICY_HWS; <br>
static const bool __maybe_unused debug_evictions; /* = false */ <br>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
<br>
index b9529948f2b2..442039436cb3 100644 <br>
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c <br>
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c <br>
@@ -169,6 +169,16 @@ uint amdgpu_sdma_phase_quantum = 32; <br>
char *amdgpu_disable_cu; <br>
char *amdgpu_virtual_display; <br>
bool enforce_isolation; <br>
+ <br>
+/* Specifies the default granularity for SVM, used in buffer <br>
+ * migration and restoration of backing memory when handling <br>
+ * recoverable page faults. <br>
+ * <br>
+ * The value is given as log(numPages(buffer)); for a 2 MiB <br>
+ * buffer it computes to be 9 <br>
+ */ <br>
+uint amdgpu_svm_default_granularity = 9; <br>
+ <br>
/* <br>
* OverDrive(bit 14) disabled by default <br>
* GFX DCS(bit 19) disabled by default <br>
@@ -320,6 +330,13 @@ module_param_named(pcie_gen2, amdgpu_pcie_gen2, int, 0444); <br>
MODULE_PARM_DESC(msi, "MSI support (1 = enable, 0 = disable, -1 = auto)"); <br>
module_param_named(msi, amdgpu_msi, int, 0444); <br>
<br>
+/** <br>
+ * DOC: svm_default_granularity (uint) <br>
+ * Used in buffer migration and handling of recoverable page faults <br>
+ */ <br>
+MODULE_PARM_DESC(svm_default_granularity, "SVM's default granularity in log(2^Pages), default 9 = 2^9 = 2 MiB");
<br>
+module_param_named(svm_default_granularity, amdgpu_svm_default_granularity, uint, 0644);
<br>
+ <br>
/** <br>
* DOC: lockup_timeout (string) <br>
* Set GPU scheduler timeout value in ms. <br>
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
<br>
index 9ae9abc6eb43..d6530febabad 100644 <br>
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h <br>
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h <br>
@@ -868,6 +868,12 @@ struct svm_range_list { <br>
struct task_struct *faulting_task; <br>
/* check point ts decides if page fault recovery need be dropped */ <br>
uint64_t checkpoint_ts[MAX_GPU_INSTANCE]; <br>
+ <br>
+ /* Default granularity to use in buffer migration <br>
+ * and restoration of backing memory while handling <br>
+ * recoverable page faults <br>
+ */ <br>
+ uint8_t default_granularity; <br>
}; <br>
<br>
/* Process data */ <br>
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
<br>
index b44dec90969f..624bfe317c9c 100644 <br>
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c <br>
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c <br>
@@ -309,12 +309,13 @@ static void svm_range_free(struct svm_range *prange, bool do_unmap)
<br>
} <br>
<br>
static void <br>
-svm_range_set_default_attributes(int32_t *location, int32_t *prefetch_loc, <br>
- uint8_t *granularity, uint32_t *flags) <br>
+svm_range_set_default_attributes(struct svm_range_list *svms, <br>
+ int32_t *location, uint8_t *granularity, <br>
+ int32_t *prefetch_loc, uint32_t *flags) <br>
{ <br>
*location = KFD_IOCTL_SVM_LOCATION_UNDEFINED; <br>
*prefetch_loc = KFD_IOCTL_SVM_LOCATION_UNDEFINED; <br>
- *granularity = 9; <br>
+ *granularity = svms->default_granularity; <br>
*flags = <br>
KFD_IOCTL_SVM_FLAG_HOST_ACCESS | KFD_IOCTL_SVM_FLAG_COHERENT; <br>
} <br>
@@ -358,9 +359,8 @@ svm_range *svm_range_new(struct svm_range_list *svms, uint64_t start,
<br>
bitmap_copy(prange->bitmap_access, svms->bitmap_supported, <br>
MAX_GPU_INSTANCE); <br>
<br>
- svm_range_set_default_attributes(&prange->preferred_loc, <br>
- &prange->prefetch_loc, <br>
- &prange->granularity, &prange->flags); <br>
+ svm_range_set_default_attributes(svms, &prange->preferred_loc, <br>
+ &prange->granularity, &prange->prefetch_loc, &prange->flags); <br>
<br>
pr_debug("svms 0x%p [0x%llx 0x%llx]\n", svms, start, last); <br>
<br>
@@ -2694,9 +2694,10 @@ svm_range_get_range_boundaries(struct kfd_process *p, int64_t addr,
<br>
*is_heap_stack = vma_is_initial_heap(vma) || vma_is_initial_stack(vma); <br>
<br>
start_limit = max(vma->vm_start >> PAGE_SHIFT, <br>
- (unsigned long)ALIGN_DOWN(addr, 2UL << 8)); <br>
+ (unsigned long)ALIGN_DOWN(addr, 1UL << p->svms.default_granularity));
<br>
end_limit = min(vma->vm_end >> PAGE_SHIFT, <br>
- (unsigned long)ALIGN(addr + 1, 2UL << 8)); <br>
+ (unsigned long)ALIGN(addr + 1, 1UL << p->svms.default_granularity));
<br>
+ <br>
/* First range that starts after the fault address */ <br>
node = interval_tree_iter_first(&p->svms.objects, addr + 1, ULONG_MAX); <br>
if (node) { <br>
@@ -3240,6 +3241,10 @@ int svm_range_list_init(struct kfd_process *p) <br>
if (KFD_IS_SVM_API_SUPPORTED(p->pdds[i]->dev->adev)) <br>
bitmap_set(svms->bitmap_supported, i, 1); <br>
<br>
+ /* Update default granularity to one bound by user/driver */ <br>
+ svms->default_granularity = min_t(u8, amdgpu_svm_default_granularity, 0x1B);
<o:p></o:p></p>
</blockquote>
</blockquote>
<p>the max granularity is 0x3F, 63 bits, why do you limit max granularity to 0x1B?<o:p></o:p></p>
<p>Regards,<o:p></o:p></p>
<p>Philip<o:p></o:p></p>
<p class="MsoNormal"><br>
<br>
<o:p></o:p></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal" style="margin-bottom:12.0pt">+ pr_debug("Default SVM Granularity to use: %d\n", svms->default_granularity);
<br>
+ <br>
return 0; <br>
} <br>
<br>
@@ -3767,8 +3772,8 @@ svm_range_get_attr(struct kfd_process *p, struct mm_struct *mm,
<br>
node = interval_tree_iter_first(&svms->objects, start, last); <br>
if (!node) { <br>
pr_debug("range attrs not found return default values\n"); <br>
- svm_range_set_default_attributes(&location, &prefetch_loc, <br>
- &granularity, &flags_and); <br>
+ svm_range_set_default_attributes(svms, &location, <br>
+ &granularity, &prefetch_loc, &flags_and); <br>
flags_or = flags_and; <br>
if (p->xnack_enabled) <br>
bitmap_copy(bitmap_access, svms->bitmap_supported, <br>
-- <br>
2.34.1 <o:p></o:p></p>
</blockquote>
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