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Wed, 10 Sep 2025 06:46:35 -0700 (PDT) Date: Wed, 10 Sep 2025 09:46:35 -0400 From: Johannes Weiner To: Yosry Ahmed Cc: Andrew Morton , Nhat Pham , Chengming Zhou , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] mm: remove unused zpool layer Message-ID: <20250910134635.GB1111@cmpxchg.org> References: <20250829162212.208258-1-hannes@cmpxchg.org> <20250829162212.208258-3-hannes@cmpxchg.org> <20250909151639.GF1474@cmpxchg.org> <3dmy2gxowbmq5wmpjtsb26d25k5fjev2geykik3du2ltmhrj7z@nfkwjjhndet5> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3dmy2gxowbmq5wmpjtsb26d25k5fjev2geykik3du2ltmhrj7z@nfkwjjhndet5> On Tue, Sep 09, 2025 at 08:09:22PM +0000, Yosry Ahmed wrote: > On Tue, Sep 09, 2025 at 08:08:12PM +0000, Yosry Ahmed wrote: > > On Tue, Sep 09, 2025 at 04:16:39PM +0100, Johannes Weiner wrote: > > > On Fri, Sep 05, 2025 at 06:58:47PM +0000, Yosry Ahmed wrote: > > > > On Fri, Aug 29, 2025 at 05:15:27PM +0100, Johannes Weiner wrote: > > > > > With zswap using zsmalloc directly, there are no more in-tree users of > > > > > this code. Remove it. > > > > > > > > > > Signed-off-by: Johannes Weiner > > > > > --- > > > > [..] > > > > > @@ -125,45 +122,18 @@ config ZSWAP_COMPRESSOR_DEFAULT > > > > > default "zstd" if ZSWAP_COMPRESSOR_DEFAULT_ZSTD > > > > > default "" > > > > > > > > > > -choice > > > > > - prompt "Default allocator" > > > > > - depends on ZSWAP > > > > > - default ZSWAP_ZPOOL_DEFAULT_ZSMALLOC if MMU > > > > > - help > > > > > - Selects the default allocator for the compressed cache for > > > > > - swap pages. > > > > > - The default is 'zbud' for compatibility, however please do > > > > > - read the description of each of the allocators below before > > > > > - making a right choice. > > > > > - > > > > > - The selection made here can be overridden by using the kernel > > > > > - command line 'zswap.zpool=' option. > > > > > +config ZSMALLOC > > > > > + tristate > > > > > > > > > > -config ZSWAP_ZPOOL_DEFAULT_ZSMALLOC > > > > > - bool "zsmalloc" > > > > > - select ZSMALLOC > > > > > - help > > > > > - Use the zsmalloc allocator as the default allocator. > > > > > -endchoice > > > > > +if ZSMALLOC > > > > > > > > > > -config ZSWAP_ZPOOL_DEFAULT > > > > > - string > > > > > - depends on ZSWAP > > > > > - default "zsmalloc" if ZSWAP_ZPOOL_DEFAULT_ZSMALLOC > > > > > - default "" > > > > > +menu "Zsmalloc allocator options" > > > > > + depends on ZSMALLOC > > > > > > > > > > -config ZSMALLOC > > > > > - tristate > > > > > - prompt "N:1 compression allocator (zsmalloc)" if (ZSWAP || ZRAM) > > > > > - depends on MMU > > > > > - help > > > > > - zsmalloc is a slab-based memory allocator designed to store > > > > > - pages of various compression levels efficiently. It achieves > > > > > - the highest storage density with the least amount of fragmentation. > > > > > > > > Why remove the prompt and help text here? > > > > > > We shouldn't ask users unnecessary questions. Zswap and zram are the > > > user-visible kernel options; if one of them is selected, they should > > > just quietly pull in the zsmalloc code. > > > > That's fair, although ideally we should call it out in the commit log :P > > With the commit log amended: > > Acked-by: Yosry Ahmed Thanks! Andrew, could you add this to the changelog? --- With zpool gone, zsmalloc is now always a simple dependency and no longer something the user needs to configure. Hide CONFIG_ZSMALLOC from the user and have zswap and zram pull it in as needed. ---