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b=E3Q+zmtDNgVMUah+YlSf9vBbWGR6tTqXsD9qISjT7L1McGuLeEU6YcOaYPV8E3vMo 5FxdvHcTC02fshJ9kTRpZ9KDik65jOwROJa8Lj44cTMExkR3yGGmIvX0WqE/Zxbfy0 frgu0+dy/0Wv0wNOEUGHD4G0xAT9Pqi1pGfSbfjDbavJZuWHd+VA+CYkULJDVYJeHn eCwIKuwJWYdQ2mRc4+z7suDS8x+EMBt56MyoCTk21xa9uX82BVwmnLUdhUmLds2wHm vIpnnSb1eXBQ2FtKcw4jb0+Z5uba9PAIvnrj3ZQZyIhohRKDQVPUtQVfXHT7nuhQw5 jbyPAC7ALE2Ig== From: SeongJae Park To: SeongJae Park Cc: damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: (sashiko review) [RFC PATCH v5 01/11] mm/damon/core: handle X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260410142034.83798-2-sj@kernel.org> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 56781180005 X-Stat-Signature: 7tuubbz8q6zy8yb5cm4eqejaa5defakd X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1775863953-594808 X-HE-Meta: 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 KKrvq1EB zxFuIC25n4W0QdLWsGApeZos2HiDEkvZSu3leAKrFeL7c6uWamlwxwIUKbAYywpjbZsfmfW3YEpfqnQimT7hbF5MVxsLdk02e9VDpJ3ltBBiWQupMcXDfFadqcwKMyo25vxPPCdBEu1wMPbW13pnPDGudwZEjBqLvBHrhC/YtTCmQiOgxhItMTJAiU65vszILygtCYt1GlnV+Sm6VvxIThduqU9RipaklkU26FRuvoxdcugAPMNBwHWZwjy0b8tGkBkoxRRLu5K3PVrWmHmRYvfOd8j6/Qzva+hOvxbt7JJgM2V+9jarzobqzDVDQxdXhf3wTomTTWvVHczHLGu8sj5Wz4LBfqWw8lVaM5stxTzCupk2hRUCv3TjxblMnHSGyT+AtPrtbTgOnOaVeFiLKNLrnv8LN8T7L3bISgsal8bIEoMI= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: TL; DR: sashiko found a good finding that better to be done as a separate cleanup work. This patch still seems good to go as-is. Forwarding sashiko review in a reply format with my inline comments below, for details of my view and doing discussions via mails if needed. > # review url: https://sashiko.dev/#/patchset/20260410142034.83798-2-sj@kernel.org > # start of sashiko.dev inline review > commit 2ab7d52b1eb10efa95d43a8eee7c50fd9669d56d > Author: SeongJae Park > > mm/damon/core: handle > This commit updates the core DAMOS logic to consider a quota fully charged > if the remaining quota is less than the minimum region size. This prevents > actions from being applied too frequently to specific memory areas. > > > diff --git a/mm/damon/core.c b/mm/damon/core.c > > index 12544c60531d3..8dbc365bb8e97 100644 > > --- a/mm/damon/core.c > > +++ b/mm/damon/core.c > > [ ... ] > > > @@ -2127,8 +2140,7 @@ static void damon_do_apply_schemes(struct damon_ctx *c, > > continue; > > > > /* Check the quota */ > > - if (damos_quota_is_set(quota) && > > - quota->charged_sz >= quota->esz) > > + if (damos_quota_is_full(quota, c->min_region_sz)) > > continue; > > > > if (damos_skip_charged_region(t, r, s, c->min_region_sz)) > > With this new check skipping regions when the remaining quota is less than > the minimum region size, does the truncation check in damos_apply_scheme() > become unreachable? > > Because damon_do_apply_schemes() will now only call damos_apply_scheme() > when quota->esz - quota->charged_sz >= c->min_region_sz, the ALIGN_DOWN > calculation: > > damos_apply_scheme() { > ... > if (c->ops.apply_scheme) { > if (damos_quota_is_set(quota) && > quota->charged_sz + sz > quota->esz) { > sz = ALIGN_DOWN(quota->esz - quota->charged_sz, > c->min_region_sz); > if (!sz) > goto update_stat; > ... > } > > will always result in a value greater than or equal to c->min_region_sz. > > Could the if (!sz) check and the corresponding goto update_stat be safely > removed since sz can no longer evaluate to 0? Good finding, but doing that would better to be a separate cleanup work. I will add that to my todo list, but keep this patch as is. > > > # end of sashiko.dev inline review > # review url: https://sashiko.dev/#/patchset/20260410142034.83798-2-sj@kernel.org Thanks, SJ # hkml [1] generated a draft of this mail. You can regenerate # this using below command: # # hkml patch sashiko_dev --for_forwarding \ # 20260410142034.83798-2-sj@kernel.org # # [1] https://github.com/sjp38/hackermail