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References: <20231213-zswap-dstmem-v3-0-4eac09b94ece@bytedance.com> <20231213-zswap-dstmem-v3-4-4eac09b94ece@bytedance.com>
In-Reply-To: <20231213-zswap-dstmem-v3-4-4eac09b94ece@bytedance.com>
From: Chris Li <chrisl@kernel.org>
Date: Tue, 19 Dec 2023 04:47:14 -0800
Message-ID: <CAF8kJuOnBhVRcC9bPJrqSDQYynbG+CpJDveFn9MJNmsBsFyM+g@mail.gmail.com>
Subject: Re: [PATCH v3 4/6] mm/zswap: cleanup zswap_load()
To: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Seth Jennings <sjenning@redhat.com>, Yosry Ahmed <yosryahmed@google.com>, 
	Vitaly Wool <vitaly.wool@konsulko.com>, Dan Streetman <ddstreet@ieee.org>, 
	Johannes Weiner <hannes@cmpxchg.org>, Andrew Morton <akpm@linux-foundation.org>, 
	Nhat Pham <nphamcs@gmail.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org
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On Mon, Dec 18, 2023 at 3:50=E2=80=AFAM Chengming Zhou
<zhouchengming@bytedance.com> wrote:
>
> After the common decompress part goes to __zswap_load(), we can cleanup
> the zswap_load() a little.
>
> Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
> ---
>  mm/zswap.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/mm/zswap.c b/mm/zswap.c
> index 3433bd6b3cef..86886276cb81 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -1759,7 +1759,6 @@ bool zswap_load(struct folio *folio)
>         struct zswap_tree *tree =3D zswap_trees[type];
>         struct zswap_entry *entry;
>         u8 *dst;
> -       bool ret;
>
>         VM_WARN_ON_ONCE(!folio_test_locked(folio));
>
> @@ -1776,19 +1775,16 @@ bool zswap_load(struct folio *folio)
>                 dst =3D kmap_local_page(page);
>                 zswap_fill_page(dst, entry->value);
>                 kunmap_local(dst);
> -               ret =3D true;
> -               goto stats;
> +       } else {
> +               __zswap_load(entry, page);

Very minor nitpick. I think this change you only take out the "ret",
you don't have to remove the goto. Personally I prefer the one with
the goto because If (!entry->length) is a rare case, having them
indented match the normal execution flow is the streamlined one
without indentation.

If you keep the else statement without the goto. You can move
__zswap_load(entry,page) to the if statement so most common case go
through the if statement rather than else.

I also think this commit can fold into the previous one. As I said,
this is minor comment, it is your call.

Acked-by: Chis Li <chrisl@kernel.org> (Google)

Chris