Hi, Tao Thanks for the work. On Mon, Sep 19, 2022 at 11:10 PM <crash-utility-request(a)redhat.com&gt; wrote: > Date: Mon, 19 Sep 2022 23:10:22 +0800 > From: Tao Liu <ltao(a)redhat.com&gt; > To: crash-utility(a)redhat.com > Subject: [Crash-utility] [RFC] [PATCH 0/6] Add maple tree vma > iteration support for crash > Message-ID: <20220919151028.25830-1-ltao(a)redhat.com&gt; > Content-Type: text/plain; charset="US-ASCII"; x-default=true > > Patchset [1] introduces maple tree data structure for linux, and the > modification on mm subsystem. > > The main impact on crash utility, is the modification on vm_area_struct. > Patch [2][3] removed the rbtree and linked list iteration of > vm_area_struct, making it impossible for crash to iterate vma > in the traditional way. For example, we can observe the failing > of crash cmd vm/fuser on kernel which has integrated with patchset [1]. > > This patchset deals with the issue by porting and adapting > kernel's maple tree vma iteration code to crash utility. It has been > tested on linux-next-next-20220914 [4]. > > Good job. But I still have several questions about the patchset. Can you help try to tidy up the following patches? For example: Step 1: - introduce the maple tree data structures and iterative algorithms as one patch. - (they include two files: maple_tree.c, maple_tree.h) Patch 1: the pure copy-and-paste work, extracting related kernel > structures, functions, constants to crash. > Patch 2: minimal code modification for crash adaption, kernel > structures are kept for member resolving. > Patch 3: modification on crash memory.c to use the maple vma > iteration. > > The idea is to make patch 1-3 a POC work. > > Step 2: - imitate the do_rbtree(), do_radix_tree(), do_xarray()..., you could refer to the filesys.c/tools.c - the maple tree can be considered as a new structure and algorithm, just like the rbtree, radix_tree and xarray..., crash can keep the same code style. - the advantage is that it is easy to maintain in the future.