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

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Date:   Mon, 17 Apr 2023 12:52:32 +0900
From:   Sergey Senozhatsky <senozhatsky@...omium.org>
To:     Yu Zhao <yuzhao@...gle.com>
Cc:     Sergey Senozhatsky <senozhatsky@...omium.org>,
        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 (23/04/16 20:55), Yu Zhao wrote:
> > Do you run some specific test?
> 
> E.g.,
>   tools/testing/selftests/kvm/max_guest_memory_test -c 112 -m 800 -s 800
> with 112 CPUs and ~770GB DRAM + 32GB zram.

Hmm ...

Something like this maybe?

The src zspage pointer is not NULL-ed after non-empty zspage is
put back to corresponding fullness list.

---

@@ -2239,8 +2241,8 @@ static unsigned long __zs_compact(struct zs_pool *pool,
                if (fg == ZS_INUSE_RATIO_0) {
                        free_zspage(pool, class, src_zspage);
                        pages_freed += class->pages_per_zspage;
-                       src_zspage = NULL;
                }
+               src_zspage = NULL;

                if (get_fullness_group(class, dst_zspage) == ZS_INUSE_RATIO_100
                    || spin_is_contended(&pool->lock)) {