From: Linus Torvalds <torvalds@linux-foundation.org>
To: Peter Xu <peterx@redhat.com>
Cc: Linux-MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Hugh Dickins <hughd@google.com>,
John Hubbard <jhubbard@nvidia.com>, Jan Kara <jack@suse.cz>,
Kirill Shutemov <kirill@shutemov.name>,
Jason Gunthorpe <jgg@nvidia.com>,
Andrew Morton <akpm@linux-foundation.org>,
Kirill Tkhai <ktkhai@virtuozzo.com>,
Michal Hocko <mhocko@suse.com>, Oleg Nesterov <oleg@redhat.com>,
Jann Horn <jannh@google.com>,
Matthew Wilcox <willy@infradead.org>,
Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH 2/3] mm: gup: allow FOLL_PIN to scale in SMP
Date: Thu, 6 May 2021 19:34:07 -0700 [thread overview]
Message-ID: <CAHk-=wiNwNz33SEdZixX62XyEx4ZPPbkkNw+V4nn+9=YLc2Acw@mail.gmail.com> (raw)
In-Reply-To: <20210506232537.165788-3-peterx@redhat.com>
On Thu, May 6, 2021 at 4:25 PM Peter Xu <peterx@redhat.com> wrote:
>
> + if (flags & FOLL_PIN && !atomic_read(&mm->has_pinned))
Please add parentheses to clarify code like this and make the grouping
much more visually obvious.
Yes, yes, '&' has higher precedence than '&&'. This is not about the
compiler, this is about the humans reading it. So please write it as
if ((flags & FOLL_PIN) && !atomic_read(&mm->has_pinned))
instead (this problem remains - and the fix is the same - in the 3/3 patch).
Otherwise the series looks fine to me (although admittedly I do find
the commit message to be ridiculously verbose for such a trivial patch
- at some point the actual _point_ if it all gets hidden in the long
commit message).
Linus
next prev parent reply other threads:[~2021-05-07 2:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-06 23:25 [PATCH 0/3] mm/gup: Fix pin page write cache bouncing on has_pinned Peter Xu
2021-05-06 23:25 ` [PATCH 1/3] mm/gup_benchmark: Support threading Peter Xu
2021-05-07 4:37 ` John Hubbard
2021-05-07 14:04 ` Peter Xu
2021-05-06 23:25 ` [PATCH 2/3] mm: gup: allow FOLL_PIN to scale in SMP Peter Xu
2021-05-07 2:34 ` Linus Torvalds [this message]
2021-05-07 6:07 ` John Hubbard
2021-05-07 14:13 ` Peter Xu
2021-05-06 23:25 ` [PATCH 3/3] mm: gup: pack has_pinned in MMF_HAS_PINNED Peter Xu
2021-05-07 6:42 ` John Hubbard
2021-05-07 7:39 ` Linus Torvalds
2021-05-07 11:14 ` Matthew Wilcox
2021-05-07 14:34 ` Peter Xu
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