Dun, I can understand what you are trying to describe in the commit message. I have some suggestions/questions that might help you refine the commit message a bit better.
Code changes look good to me. Thanks, Ray > -----Original Message----- > From: Tan, Dun <dun....@intel.com> > Sent: Thursday, May 18, 2023 2:37 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] 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 the > allocated 4 pages. If the limit address is already 8KB aligned, then 1. What's "limit address"? > 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 lower address, then the higher 2 pages cann't be merged > 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 limit > of allocated 3 pages is 8KB-aligned, then the last 8K range will 2. What's "last 8k"? -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#105010): https://edk2.groups.io/g/devel/message/105010 Mute This Topic: https://groups.io/mt/98986400/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/leave/9847357/21656/1706620634/xyzzy [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
