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b=eYm1fJgxpp3l16wAf3hHdY2PMp/tTzeTwP7fDp9H5zKMbgEzqXUbdoayv9MO5h2C5 nJ8RPwLemSs3tGEL+MNNWSUr0IKqqzUSbjFYNENVftj/koRsijDnoEWAiyaZR58mi8 gwuIaH0FcNPDh+3lKnNXBhO6jx6sDd4VHD3T93D8wL+YPGdfjxtBZpTDYcjxDWldvs Da8V7tEH3UEg8gq+L3BmkeVVr1ks4OjpoK4Faga8zpLQ+DGoW7UepmQ3NJIABY2tHI Ki4GlTyLpCZiYH96zWNrU0u9ZHPZUt169w+4seciUde+Udt5ZWCCc/OsnozGRbKeE8 +qLTt4P44BviQ== Date: Sun, 28 Jul 2024 15:43:02 +0300 From: Mike Rapoport To: Leesoo Ahn Cc: Leesoo Ahn , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/sparse: return right away if sparsemap_buf is null Message-ID: References: <20240726071023.4078055-1-lsahn@wewakecorp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240726071023.4078055-1-lsahn@wewakecorp.com> X-Rspam-User: X-Rspamd-Queue-Id: 7AE5C140008 X-Rspamd-Server: rspam01 X-Stat-Signature: pjezb7986fk1q1gze5octw5prmwgjxfa X-HE-Tag: 1722170601-330621 X-HE-Meta: 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 CzynyM+z Sx5q9rPXDxRA0NhcfR0i0IRsjPhREN7SqzODyLxccUviwD9BF6uXbuVRx3ODaaiJbLgvap70etZthRudgwWr8h10BJaiE2dbDEF72ctSWLfLGPMiHS21H7ycgUka6+JB3ZEghfPx+3kbXBElwpGtKEboBRb/K6jMQvkRg854h0+fPhYue0Jq5xN9agE4pI/smM83oksyDhEuVuZa7sGgbBdPmVAB1+2h56rr1I7Tj/9r42msnalz89jwsziRCrbw/TdNOASK8+EOOn06aUkis9mEoZ/rUJg/bGJdd6X1gjFttRRD94nhf4RYTMt/KoMvWpj+3Ap5cTuciM4I= 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 Fri, Jul 26, 2024 at 04:10:23PM +0900, Leesoo Ahn wrote: > sparse_buffer_fini(..) takes the following actions even though the value of > sparsemap_buf is NULL, > 1. calculate size of sparsemap buffer (which is meaningless). > 2. set sparsemap_buf variable to NULL (although it is already NULL). > > These steps are unnecessary if the variable, sparsemap_buf is NULL. > > Refactor the function to return right away if the variable is NULL. > Hence, it doesn't need to take further actions. sparse_buffer_fini() is called a few times on init so saving a jump (if at all) does not worth the churn. > Signed-off-by: Leesoo Ahn > --- > mm/sparse.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/mm/sparse.c b/mm/sparse.c > index e4b830091d13..091e4bc2f72c 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -469,9 +469,13 @@ static void __init sparse_buffer_init(unsigned long size, int nid) > > static void __init sparse_buffer_fini(void) > { > - unsigned long size = sparsemap_buf_end - sparsemap_buf; > + unsigned long size; > > - if (sparsemap_buf && size > 0) > + if (!sparsemap_buf) > + return; > + > + size = sparsemap_buf_end - sparsemap_buf; > + if (size > 0) > sparse_buffer_free(size); > sparsemap_buf = NULL; > } > -- > 2.34.1 > > -- Sincerely yours, Mike.