Is this considered a critical bug for stable tag release? Is there are HSD and if it is critical, all memory allocation lobs should be fixed. Right?
Mike > -----Original Message----- > From: Ni, Ray <ray...@intel.com> > Sent: Thursday, May 18, 2023 1:55 AM > To: Tan, Dun <dun....@intel.com>; devel@edk2.groups.io > Cc: Kinney, Michael D <michael.d.kin...@intel.com>; Gao, Liming > <gaolim...@byosoft.com.cn>; Liu, Zhiguang <zhiguang....@intel.com> > Subject: RE: [Patch V2] MdePkg: Code optimization to SMM > InternalAllocateAlignedPages > > Reviewed-by: Ray Ni <ray...@intel.com> > > > -----Original Message----- > > From: Tan, Dun <dun....@intel.com> > > Sent: Thursday, May 18, 2023 3:31 PM > > To: devel@edk2.groups.io > > Cc: Ni, Ray <ray...@intel.com>; Kinney, Michael D > > <michael.d.kin...@intel.com>; Gao, Liming <gaolim...@byosoft.com.cn>; > Liu, > > Zhiguang <zhiguang....@intel.com> > > Subject: [Patch V2] MdePkg: Code optimization to SMM > > InternalAllocateAlignedPages > > > > This commit is code optimization to InternalAllocateAlignedPages of > > SmmMemoryAllocationLib which can reduce free memory fragments. Also > > it can reduce one pre-allocation page. > > > > Let's take a simple example: > > The expected pages size is 8KB, Alignment value is 8KB. > > > > In original InternalAllocateAlignedPages(), the first step is to > > allocate 4 pages and then find the first 8KB-aligned address in > > allocated 4 pages. If the upper limit address of allocated 4 pages > > is already 8KB aligned, then the allocated 4 pages contains two > > 8KB-aligned 8KB ranges. The lower 2 pages will be selected and > > removed from free pages. Then the higher 2 pages will be free. > > Since the whole memory allocation is from high address to low > > address, then the higher 2 pages cann't be merged with other free > > pages, causing the free memory fragments. > > > > However, when only allocate 3(2+2-1) pages, we can avoid the free > > memory fragments in specific case. Also 3 pages must contain a > > 8KB-aligned 8KB range, which meets the requirement. If the upper > > limit address of allocated 3 pages is 8KB-aligned, then the higher > > 2 pages range of allocated 3 pages is 8KB-aligned and will be > > selected and removed from free pages. The remaining lower one page > > of allocated 3 pages will be free and merged with left lower free > > memory. This can reduce free memory fragments in smm. > > > > Signed-off-by: Dun Tan <dun....@intel.com> > > Cc: Ray Ni <ray...@intel.com> > > Cc: Michael D Kinney <michael.d.kin...@intel.com> > > Cc: Liming Gao <gaolim...@byosoft.com.cn> > > Cc: Zhiguang Liu <zhiguang....@intel.com> > > --- > > MdePkg/Library/SmmMemoryAllocationLib/MemoryAllocationLib.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git > a/MdePkg/Library/SmmMemoryAllocationLib/MemoryAllocationLib.c > > b/MdePkg/Library/SmmMemoryAllocationLib/MemoryAllocationLib.c > > index 3ab2c1ebfd..99a8259325 100644 > > --- a/MdePkg/Library/SmmMemoryAllocationLib/MemoryAllocationLib.c > > +++ b/MdePkg/Library/SmmMemoryAllocationLib/MemoryAllocationLib.c > > @@ -322,7 +322,7 @@ InternalAllocateAlignedPages ( > > // Calculate the total number of pages since alignment is larger than > page size. > > // > > AlignmentMask = Alignment - 1; > > - RealPages = Pages + EFI_SIZE_TO_PAGES (Alignment); > > + RealPages = Pages + EFI_SIZE_TO_PAGES (Alignment) - 1; > > // > > // Make sure that Pages plus EFI_SIZE_TO_PAGES (Alignment) does not > > overflow. > > // > > -- > > 2.31.1.windows.1 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#105037): https://edk2.groups.io/g/devel/message/105037 Mute This Topic: https://groups.io/mt/98986911/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/leave/9847357/21656/1706620634/xyzzy [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
