Mike,
Thanks for your comment. I have additional comment for current design.
I know there is a requirement for UEFI S4 resume that need to have consistent
memory map and OS using gBS->GetMemoryMap() for such check.
CoreGetMemoryMap returned UEFI memory map based on the information conveyed via
gMemoryTypeInformation[] which is the same pointer DXE core installs into
ConfigurationTable.
Yes, from current implement, it logs only peak usage but I am curious about why
it should not reflect the real usage for current boot. (Differ to what EDK
version had implemented.)
If we look from current UEFI memory management, PEI phase use either existing
UEFI variable or predefined configuration to create
gEfiMemoryTypeInformationGuid GUIDed Hob. DXE Core uses this HOB during
CoreInitializeMemoryServices() for pre-allocate memory bins for different type
of memory. Platform design might choose to handle estimated BIN size does not
fit to current memory usage we get from mMemoryTypeStatistics[] via (1) Update
MemoryTypeInformation UEFI variable and (2) Triggers a platform reset for
adjusting bin size in the next boot path which accommodate real memory usage
model.
If there is a DXE driver which allocates a memory band for tentative
operational use and finally get freed when done, current implement will not
reflect this change to gMemoryTypeInformation[] that mismatch to
mMemoryTypeStatistics[] and the bin adjustment process performed that caused we
pre-allocate bigger bin size that real active components are using. It will not
hurt anything but will it better we even don’t need to do the additional bin
adjustment if the gMemoryTypeInformation[] always been updated to match real
memory usage? In this way, we get a more compact memory map and not leaving
available memory band at the end of each memory bin.
Thanks,
- Mars
寄件者: Kinney, Michael D [mailto:[email protected]]
寄件日期: 2014年7月15日 上午 05:41
收件者: [email protected]
主旨: Re: [edk2] Memory usage does not get updated when free the allocated one
Mars Lin,
The purpose of the gEfiMemoryTypeInformationGuid system configuration table is
to track the peak usage of each memory type. Not the current usage. The
internal data structure mMemoryTypeStatistics tracks the current usage of each
memory type.
We need to know the peak usage of each memory type so the size of each memory
type bin can be set to guarantee that all the allocations during an entire boot
can fit within that bin.
I think your proposed change could produce a bin size that is smaller than the
peak, which could result in S4 resume failures for some operating systems.
Do you agree?
Thanks,
Mike
From: Mars Lin [mailto:[email protected]]
Sent: Monday, July 14, 2014 3:04 AM
To: [email protected]<mailto:[email protected]>
Subject: [edk2] Memory usage does not get updated when free the allocated one
Dear MdeModulePkg maintainer,
Please review attached patch file which try to correct the MemoryTypeInfo does
not get updated within CoreConvertPages().
Steps to reproduce:
0. EfiLibGetSystemConfigurationTable (&gEfiMemoryTypeInformationGuid,
&CurrentMemoryTypeInformation1)
1. AllocatePool (EfiBootServicesData, 0x80000, &BsData);
2. EfiLibGetSystemConfigurationTable (&gEfiMemoryTypeInformationGuid,
&CurrentMemoryTypeInformation2)
3. FreePool (BsData)
4. EfiLibGetSystemConfigurationTable (&gEfiMemoryTypeInformationGuid, &
CurrentMemoryTypeInformation3)
#1. CurrentMemoryTypeInformation2 get updated with EfiBootServicesData type
grow 128 pages compare to CurrentMemoryTypeInformation1==> Correct!
#2. CurrentMemoryTypeInformation3 does not get updated with EfiBootServicesData
type reduced 128 pages compare to CurrentMemoryTypeInformation2==> Problem!
----------------------------------------------------------------------------------------------------------------------
MdeModulePkg: Memory usage does not get updated when free the allocated one
Update gMemoryTypeInfo array when specific memory type been freed.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Smith Cheng
<[email protected]<mailto:[email protected]>>
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