linux-kernel - Re: [PATCHv4 0/4] zsmalloc: fine-grained fullness and new compaction algorithm

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Date:   Sun, 16 Apr 2023 01:20:37 -0600
From:   Yu Zhao <yuzhao@...gle.com>
To:     Sergey Senozhatsky <senozhatsky@...omium.org>
Cc:     Minchan Kim <minchan@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Yosry Ahmed <yosryahmed@...gle.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCHv4 0/4] zsmalloc: fine-grained fullness and new compaction algorithm

On Fri, Mar 3, 2023 at 8:48 PM Sergey Senozhatsky
<senozhatsky@...omium.org> wrote:
>
>         Hi,
>
> Existing zsmalloc page fullness grouping leads to suboptimal page
> selection for both zs_malloc() and zs_compact(). This patchset
> reworks zsmalloc fullness grouping/classification.
>
> Additinally it also implements new compaction algorithm that is
> expected to use less CPU-cycles (as it potentially does fewer
> memcpy-s in zs_object_copy()).
>
> Test (synthetic) results can be seen in patch 0003.

Seeing the following crashes from mm-unstable. Please take a look. Thanks.

  list_add corruption. next is NULL.
  kernel BUG at lib/list_debug.c:26!
  Call Trace:
   <TASK>
   zs_compact+0xbf6/0xda0
   zs_shrinker_scan+0x19/0x30
   do_shrink_slab+0x1ac/0x450
   shrink_slab+0xdc/0x3d0
   shrink_one+0xe2/0x1d0
   shrink_node+0xc7f/0xea0
   do_try_to_free_pages+0x1b5/0x500
   try_to_free_pages+0x396/0x5d0
   __alloc_pages_slowpath+0x5d0/0x1030
   __alloc_pages+0x1de/0x280
   __folio_alloc+0x1e/0x40
   vma_alloc_folio+0x4c0/0x530
   shmem_alloc_and_acct_folio+0x1a6/0x3b0
   shmem_get_folio_gfp+0x689/0xf00
   shmem_fault+0x81/0x240