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b=b5sUKZOU429aGue5jA1Ng8scXotKK10GgtDEDHLY1uH2vKa9ClNbNk5NbtxgbnS7Q nqjz1W43MtpbmlhhfCe8/zdbwA4+bAWLwWqw2GqA1+SBxszj3fL/djkV5e95nobMDa xLR92isA5PkcLRFHbB091/WOazwR6XiZiV3ZPqwY= Date: Mon, 1 Jul 2024 23:52:10 -0700 From: Andrew Morton To: Barry Song <21cnbao@gmail.com> Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Barry Song , Yosry Ahmed , Nhat Pham , Chengming Zhou , Chris Li , David Hildenbrand , Johannes Weiner , Matthew Wilcox Subject: Re: [PATCH] mm: zswap: fix zswap_never_enabled() for CONFIG_ZSWAP==N Message-Id: <20240701235210.5c187c85aa225292d034cafc@linux-foundation.org> In-Reply-To: <20240629232231.42394-1-21cnbao@gmail.com> References: <20240629232231.42394-1-21cnbao@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: CFE59140011 X-Stat-Signature: 7kur63343p1pkyd15ob6m8c1w7g673yr X-HE-Tag: 1719903135-444320 X-HE-Meta: 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 6bVhUA63 OuFVQe2xi/gbOnAEe9YrCUblDlYAtQA+nTo3EdIVv2X47EIGIpn8DWH+1zKB4tpR2PbCYLJNgZXWyQcZDdJFjH75tuoI9tgc1PqcmiBXV9+fvoZ/MHuHa+VZO2fnSSCTOqFr2N+jwlDRu5cdgA0Ed1m5NPMj8mxnptAMOXLr9+bILzV1WX2aG/rYDQUn7cMrg3iMM4PjfJWXeo2RCKzI1NhrdjXDAuDzBAo/OspGt0tCmZWhicJJf5nadqiu6wZcPsGIp9iGlEfkkHYKmuuZWqefOaAGVsCQa3zibNP7DzyzNNByoH7cD8pqpyJ0W4BBBVN9jm8Fn+sdkvuB+TFuUI7zxtJKIcZ8Puxx2UIm/kFMroKIYSH3CHs19N7/ebp+q7FWERouDKNlN6GCOKxB9YhGQYg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, 30 Jun 2024 11:22:31 +1200 Barry Song <21cnbao@gmail.com> wrote: > From: Barry Song > > If CONFIG_ZSWAP is set to N, it means zswap cannot be enabled. > zswap_never_enabled() should return true. > > ... > > --- a/include/linux/zswap.h > +++ b/include/linux/zswap.h > @@ -68,7 +68,7 @@ static inline bool zswap_is_enabled(void) > > static inline bool zswap_never_enabled(void) > { > - return false; > + return true; > } Well, that code was as wrong as it's possible to get. But what effect does this have? Seems "not much"? Perhaps we'll attempt a zswap_load() which later fails for other reasons?