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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pFOBJ-003cWt-Mg; Tue, 10 Jan 2023 23:37:25 +0000 Date: Tue, 10 Jan 2023 23:37:25 +0000 From: Matthew Wilcox To: Andrew Morton 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: References: <740a2396d9b98154dba76e326cba5e798b640ead.1673342761.git.baolin.wang@linux.alibaba.com> <20230110152532.8b2d34bf04d7b8e9a4e39130@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230110152532.8b2d34bf04d7b8e9a4e39130@linux-foundation.org> X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: E9D53C0008 X-Stat-Signature: kr98s56ptn1zu3igg6s4pay9nqx6ib4j X-HE-Tag: 1673393844-296653 X-HE-Meta: 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 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, Jan 10, 2023 at 03:25:32PM -0800, Andrew Morton wrote: > 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? What if compaction_suitable() is modified to return another value? This seems like a relatively innocuous check.