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bh=WgtCtfLuwYiDuoh7TNoyHB+vCe9fN558duUfvgaF3Yw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=bu3OT7DS7oq2rnBxcbUKoOC7omsp7pl+aG21lq0ziECOw04lojlobWm/+cBcgNXqy eYyGjWKgqDAWNJ9LY41S4ThzRfeqv3FrPE5wnoPr/tV4tEModvmDvhX4OYb4MzvRBZ L377iHH3WLd4VjIWaatP8eGI9QYvgN+rJ54Kn5NM= Date: Tue, 10 Jan 2023 15:25:32 -0800 From: Andrew Morton To: Matthew Wilcox Cc: Baolin Wang , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/5] mm: compaction: Remove redundant VM_BUG_ON() in compact_zone() Message-Id: <20230110152532.8b2d34bf04d7b8e9a4e39130@linux-foundation.org> In-Reply-To: References: <740a2396d9b98154dba76e326cba5e798b640ead.1673342761.git.baolin.wang@linux.alibaba.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 0A85540010 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: ohgwbfnc1j75g3gjhnftzxgcpeeqeshf X-HE-Tag: 1673393134-718085 X-HE-Meta: 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 L+Ts1byn k719SP2WIobIOihRQ/lceLddDQZD8hPi5CleRXag2Ak6VqF6TxOxZ5fur+g8k7IqGgyVi6zk8bXAHcIC+F2ZOgxnRmDdr7uX2BiVJ24NZVWXtk3aBhHwU3ZemQQ== 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: On Tue, 10 Jan 2023 13:37:57 +0000 Matthew Wilcox wrote: > On Tue, Jan 10, 2023 at 09:36:18PM +0800, Baolin Wang wrote: > > The compaction_suitable() will never return values other than COMPACT_SUCCESS, > > COMPACT_SKIPPED and COMPACT_CONTINUE, so after validation of COMPACT_SUCCESS > > and COMPACT_SKIPPED, we will never hit other unexpected case. Thus remove > > the redundant VM_BUG_ON() validation for the return values of compaction_suitable(). > > I don't understand why we'd remove this check. Well, just from code inspection it serves no purpose. Such an assertion might be useful during early code development, but I think we can consider compaction_suitable() to adequately debugged by now?