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[73.93.239.127]) by smtp.gmail.com with ESMTPSA id c6sm396906pgl.38.2020.12.02.10.27.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Dec 2020 10:27:44 -0800 (PST) From: Yang Shi To: guro@fb.com, ktkhai@virtuozzo.com, shakeelb@google.com, david@fromorbit.com, hannes@cmpxchg.org, mhocko@suse.com, akpm@linux-foundation.org Cc: shy828301@gmail.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/9] mm: vmscan: simplify nr_deferred update code Date: Wed, 2 Dec 2020 10:27:17 -0800 Message-Id: <20201202182725.265020-2-shy828301@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201202182725.265020-1-shy828301@gmail.com> References: <20201202182725.265020-1-shy828301@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently if (next_deferred - scanned) = 0, the code would just read the current nr_deferred otherwise add the delta back. Both needs atomic operation anyway, it seems there is not too much gain by distinguishing the two cases, so just add the delta back even though the delta is 0. This would simply the code for the following patches too. Signed-off-by: Yang Shi --- mm/vmscan.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 7b4e31eac2cf..7d6186a07daf 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -528,14 +528,10 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl, next_deferred = 0; /* * move the unused scan count back into the shrinker in a - * manner that handles concurrent updates. If we exhausted the - * scan, there is no need to do an update. + * manner that handles concurrent updates. */ - if (next_deferred > 0) - new_nr = atomic_long_add_return(next_deferred, - &shrinker->nr_deferred[nid]); - else - new_nr = atomic_long_read(&shrinker->nr_deferred[nid]); + new_nr = atomic_long_add_return(next_deferred, + &shrinker->nr_deferred[nid]); trace_mm_shrink_slab_end(shrinker, nid, freed, nr, new_nr, total_scan); return freed; -- 2.26.2