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From: Andrew Morton <akpm@linux-foundation.org>
To: Hugh Dickins <hughd@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>,
	Minchan Kim <minchan@kernel.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Michal Hocko <mhocko@suse.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/mmap: replace if (cond) BUG() with BUG_ON()
Date: Wed, 6 Jan 2021 11:46:20 -0800	[thread overview]
Message-ID: <20210106114620.5c221690f3a9cad7afcc3077@linux-foundation.org> (raw)
In-Reply-To: <alpine.LSU.2.11.2101051919130.1361@eggly.anvils>

On Tue, 5 Jan 2021 20:28:27 -0800 (PST) Hugh Dickins <hughd@google.com> wrote:

> Alex, please consider why the authors of these lines (whom you
> did not Cc) chose to write them without BUG_ON(): it has always
> been preferred practice to use BUG_ON() on predicates, but not on
> functionally effective statements (sorry, I've forgotten the proper
> term: I'd say statements with side-effects, but here they are not
> just side-effects: they are their main purpose).
> 
> We prefer not to hide those away inside BUG macros

Should we change that?  I find BUG_ON(something_which_shouldnt_fail())
to be quite natural and readable.

As are things like the existing

BUG_ON(mmap_read_trylock(mm));
BUG_ON(wb_domain_init(&global_wb_domain, GFP_KERNEL));

etc.


No strong opinion here, but is current mostly-practice really
useful?



  parent reply	other threads:[~2021-01-06 19:46 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-12  3:26 [PATCH] mm/zsmalloc: " Alex Shi
2020-12-12  3:26 ` [PATCH] mm/mmap: " Alex Shi
2020-12-12  3:52   ` Alex Shi
2021-01-06  4:28     ` Hugh Dickins
2021-01-06  8:40       ` Alex Shi
2021-01-06 19:46       ` Andrew Morton [this message]
2021-01-06 20:09         ` Andrea Arcangeli
2021-01-06 20:18           ` Hugh Dickins
2021-01-06 20:42             ` Andrew Morton
2021-01-07 17:28             ` Vlastimil Babka
2021-01-07 17:36               ` Andrea Arcangeli
2021-01-07 17:45                 ` Vlastimil Babka
2021-01-06 20:10         ` Hugh Dickins
2021-01-07  8:33           ` Michal Hocko
2020-12-21 16:41 ` [PATCH] mm/zsmalloc: " Minchan Kim

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