Sure. I'll change them. Thanks.
Regards,
Jian
> -----Original Message-----
> From: Zeng, Star
> Sent: Thursday, October 25, 2018 11:23 AM
> To: Wang, Jian J <jian.j.w...@intel.com>; edk2-devel@lists.01.org
> Cc: Kinney, Michael D <michael.d.kin...@intel.com>; Ni, Ruiyu
> <ruiyu...@intel.com>; Yao, Jiewen <jiewen....@intel.com>; Laszlo Ersek
> <ler...@redhat.com>; Zeng, Star <star.z...@intel.com>
> Subject: Re: [edk2] [PATCH v3 5/6] MdeModulePkg/Core: prevent re-acquire
> GCD memory lock
>
> Some minor comments are added below.
> With them addressed, Reviewed-by: Star Zeng <star.z...@intel.com>.
>
> On 2018/10/24 13:26, Jian J Wang wrote:
> >> v3 changes:
> >> a. drop the changes to CoreGetIoSpaceMap() because it won't cause
> >> problem
> >> b. refine the logic in changes of CoreGetMemorySpaceMap()
> >> and add more comments
> >
> > This issue is hidden in current code but exposed by introduction
> > of freed-memory guard feature due to the fact that the feature
> > will turn all pool allocation to page allocation.
> >
> > The solution is move the memory allocation in CoreGetMemorySpaceMap()
>
> Use 'moving' instead of 'move'?
>
> > and CoreGetIoSpaceMap() to be out of the GCD memory map lock.
>
> Please remove CoreGetIoSpaceMap() as the code does not touch it at all.
>
> >
> > Although it's rare, a while-loop is added to make sure that the count
> > of descriptor of memory map is the same after memory allocation, because
> > it's executed outside the GCD memory lock.
> >
> > CoreDumpGcdMemorySpaceMap()
> > => CoreGetMemorySpaceMap()
> > => CoreAcquireGcdMemoryLock () *
> > AllocatePool()
> > => InternalAllocatePool()
> > => CoreAllocatePool()
> > => CoreAllocatePoolI()
> > => CoreAllocatePoolPagesI()
> > => CoreAllocatePoolPages()
> > => FindFreePages()
> > => PromoteMemoryResource()
> > => CoreAcquireGcdMemoryLock() **
> >
> > Cc: Star Zeng <star.z...@intel.com>
> > Cc: Michael D Kinney <michael.d.kin...@intel.com>
> > Cc: Jiewen Yao <jiewen....@intel.com>
> > Cc: Ruiyu Ni <ruiyu...@intel.com>
> > Cc: Laszlo Ersek <ler...@redhat.com>
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Jian J Wang <jian.j.w...@intel.com>
> > ---
> > MdeModulePkg/Core/Dxe/Gcd/Gcd.c | 80 +++++++++++++++++++++++++++-
> -------------
> > 1 file changed, 54 insertions(+), 26 deletions(-)
> >
> > diff --git a/MdeModulePkg/Core/Dxe/Gcd/Gcd.c
> b/MdeModulePkg/Core/Dxe/Gcd/Gcd.c
> > index d9c65a8045..bc02945721 100644
> > --- a/MdeModulePkg/Core/Dxe/Gcd/Gcd.c
> > +++ b/MdeModulePkg/Core/Dxe/Gcd/Gcd.c
> > @@ -1691,10 +1691,10 @@ CoreGetMemorySpaceMap (
> > OUT EFI_GCD_MEMORY_SPACE_DESCRIPTOR **MemorySpaceMap
> > )
> > {
> > - EFI_STATUS Status;
> > LIST_ENTRY *Link;
> > EFI_GCD_MAP_ENTRY *Entry;
> > EFI_GCD_MEMORY_SPACE_DESCRIPTOR *Descriptor;
> > + UINTN DescriptorCount;
> >
> > //
> > // Make sure parameters are valid
> > @@ -1706,38 +1706,66 @@ CoreGetMemorySpaceMap (
> > return EFI_INVALID_PARAMETER;
> > }
> >
> > + *NumberOfDescriptors = 0;
> > + *MemorySpaceMap = NULL;
> > +
> > CoreAcquireGcdMemoryLock ();
>
> Better to add comment for it like below quoted from the example at
> https://lists.01.org/pipermail/edk2-devel/2018-October/031279.html given
> by Laszlo.
>
> //
> // Take the lock, for entering the loop with the lock held.
> //
>
> >
> > - //
> > - // Count the number of descriptors
> > - //
> > - *NumberOfDescriptors = CoreCountGcdMapEntry
> (&mGcdMemorySpaceMap);
> > + while (TRUE) {
> > + //
> > + // Count the number of descriptors. It might be done more than once
> because
>
> Use 'count' instead of 'number' to match the variable name?
>
> > + // there's code which has to be running outside the GCD lock.
>
> Use "AllocatePool() calling code below" instead of "there's code"?
>
> > + //
> > + DescriptorCount = CoreCountGcdMapEntry (&mGcdMemorySpaceMap);
> > + if (DescriptorCount == *NumberOfDescriptors) {
> > + //
> > + // Fill in the MemorySpaceMap if no memory space map change.
> > + //
> > + Descriptor = *MemorySpaceMap;
> > + Link = mGcdMemorySpaceMap.ForwardLink;
> > + while (Link != &mGcdMemorySpaceMap) {
> > + Entry = CR (Link, EFI_GCD_MAP_ENTRY, Link,
> EFI_GCD_MAP_SIGNATURE);
> > + BuildMemoryDescriptor (Descriptor, Entry);
> > + Descriptor++;
> > + Link = Link->ForwardLink;
> > + }
> >
> > - //
> > - // Allocate the MemorySpaceMap
> > - //
> > - *MemorySpaceMap = AllocatePool (*NumberOfDescriptors * sizeof
> (EFI_GCD_MEMORY_SPACE_DESCRIPTOR));
> > - if (*MemorySpaceMap == NULL) {
> > - Status = EFI_OUT_OF_RESOURCES;
> > - goto Done;
> > - }
> > + break;
> > + }
> >
> > - //
> > - // Fill in the MemorySpaceMap
> > - //
> > - Descriptor = *MemorySpaceMap;
> > - Link = mGcdMemorySpaceMap.ForwardLink;
> > - while (Link != &mGcdMemorySpaceMap) {
> > - Entry = CR (Link, EFI_GCD_MAP_ENTRY, Link, EFI_GCD_MAP_SIGNATURE);
> > - BuildMemoryDescriptor (Descriptor, Entry);
> > - Descriptor++;
> > - Link = Link->ForwardLink;
> > + //
> > + // Release the lock before memory allocation, because it might cause
> > + // GCD lock conflict in one of calling path in AllocatPool().
> > + //
> > + CoreReleaseGcdMemoryLock ();
> > +
> > + //
> > + // Allocate memory to store the MemorySpaceMap. Note it might be
> already
> > + // allocated if there's map descriptor change during memory allocation
> > at
> > + // last time.
> > + //
> > + if (*MemorySpaceMap != NULL) {
> > + FreePool (*MemorySpaceMap);
> > + }
> > +
> > + *MemorySpaceMap = AllocatePool (DescriptorCount *
> > + sizeof
> > (EFI_GCD_MEMORY_SPACE_DESCRIPTOR));
> > + if (*MemorySpaceMap == NULL) {
> > + *NumberOfDescriptors = 0;
> > + return EFI_OUT_OF_RESOURCES;
> > + }
> > +
> > + //
> > + // Save the descriptor number got before for another round of check to
> make
>
> Use 'count' instead of 'number' to match the variable name?
>
> > + // sure we won't miss any, since we have code running outside the GCD
> lock.
> > + //
> > + *NumberOfDescriptors = DescriptorCount;
> > + CoreAcquireGcdMemoryLock ();
>
> Better to add comment for it like below quoted from the example at
> https://lists.01.org/pipermail/edk2-devel/2018-October/031279.html given
> by Laszlo.
>
> //
> // Re-acquire the lock, for the next iteration.
> //
>
> > }
> > - Status = EFI_SUCCESS;
> >
> > -Done:
> > CoreReleaseGcdMemoryLock ();
>
> Better to add comment for it like below quoted from the example at
> https://lists.01.org/pipermail/edk2-devel/2018-October/031279.html given
> by Laszlo.
>
> //
> // We exited the loop with the lock held, release it.
> //
>
>
> Thanks,
> Star
>
> > - return Status;
> > +
> > + return EFI_SUCCESS;
> > }
> >
> >
> >
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