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b=BwYVRuQ3+jmYVOnw/z8CebDR+LNz8kgr/CPQcAxMUOha8IjB4i7VZajFRhyWLuqtB q9TepgLNsgS7Jb4tOeJm8PDeo61l/KRfxdxIFVOVf4TsQUd9Vm5tQ1N1UQfdsazrUb iPNyRpeVOgme/P5NUsn0f+MHjoY3Vc4rmKXQL15Td9oi77VU7OZhp13RYijWXWvmgn x/yMNpxtA4FfVnarTOOFCre6EWFUg1+3+RJUV9tRXPA4etZk8oMMVgtWBitvbsMVJm vlgvvGm8nSN1aE0SBLNCls2Zo4ae144ELao1ZMKnh7+4aS37Q3hb6oQf1C/ty7OfHN cmpRAt0jGMkLw== From: SJ Park To: sashiko-bot@kernel.org Cc: SJ Park , "Andrew Morton" , damon@lists.linux.dev, linux-mm@kvack.org Subject: Re: [RFC PATCH 02/27] mm/damon/core: implement data attribute report queue Date: Sun, 15 Nov 2026 13:17:22 -0800 Message-ID: <20261115211723.101033-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam09 X-Stat-Signature: 4p3oe61ebixfq4h9dhqmimu9mtc563u3 X-Rspamd-Queue-Id: 603E5100003 X-Rspam-User: X-HE-Tag: 1794777451-42242 X-HE-Meta: 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 a83SuS9l VUzies2BsHvWI2UE3QL4qQRH0OIcOuDdaSqs3v6/djSjyqdTSsicpr+ryrCFqXWZZvxHdRCZTjI73cDggT5DUOJ1S2JC92v7Yos4lOsYylOx8CYAegA054rIbJqqhxDIP1JvIu3+aNHitNJsq57XoDpOQYCZg0rTVNzajj0C5ZtI6Ci+fE1xVJTtxZ6WPduig6+YZTq4hDF46E2rgLBeINKkd+OY54qnm1V4elzQD/P4WbkMBbtO/eC/p4BzEcCB0CumqqdhUJ0+HXsg7vBqzF7hWtJmceXnGHL0m/vovYXErGxFOSDIvwinODI9vzIk6kI/A Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Sun, 15 Nov 2026 20:41:23 +0000 sashiko-bot@kernel.org wrote: > Thank you for your contribution! Sashiko AI review found 3 potential > issues to consider: > - [Medium] mm/damon: damon_init() leaks damon_region_cache on queue > alloc failure > - [Low] mm/damon: missing static qualifier on damon_report_queue in > core.c > - [Low] mm/damon: struct damon_report_queue comment documents head not > nr_reports > -- > > commit 10a61bc9bab6e48534e4a8552380aecaccbee97a > Author: SJ Park > > mm/damon/core: implement data attribute report queue > > This commit adds an internal damon_report_queue structure, allocates its > buffer for up to 1,000 reports in damon_init(), and checks that buffer in > damon_initialized(). > > > diff --git a/mm/damon/core.c b/mm/damon/core.c > > index 0a056949604f9..3f87a7eec442e 100644 > > --- a/mm/damon/core.c > > +++ b/mm/damon/core.c > > @@ -2334,6 +2334,25 @@ int damos_walk(struct damon_ctx *ctx, struct damos_walk_control *control) > > return 0; > > } > > > > +/* > > + * struct damon_report_queue - &struct damon_report queue. > > + * > > + * @lock: Represent if this queue is being used by someone. > > + * @head: Head of the queue. > > + * @tail: Tail of the queue. > > + * @size: Size of the queue. > > + * @reports: Array of &struct damon_report. > > + */ > > +struct damon_report_queue { > > + atomic_t lock; > > + unsigned int tail; > > + unsigned int size; > > + unsigned int nr_reports; > > + struct damon_report *reports; > > +}; > > [Severity: Low] > The comment above struct damon_report_queue documents @head, whereas the > struct defines nr_reports instead. Nice catch. I will remove the comment for @head and add a comment for @nr_reports. > > > + > > +struct damon_report_queue damon_report_queue; > > [Severity: Low] > Should damon_report_queue be marked static? struct damon_report_queue is > private to mm/damon/core.c, so leaving damon_report_queue non-static > exports it into the global namespace and triggers sparse and W=1 missing > variable declaration warnings. Good suggestion, I will mark it as static. > > > + > > /* > > * Reset the aggregated monitoring results ('nr_accesses' of each region). > > */ > > @@ -4308,7 +4327,7 @@ void damon_update_region_access_rate(struct damon_region *r, bool accessed) > > */ > > bool damon_initialized(void) > > { > > - return damon_region_cache != NULL; > > + return damon_region_cache && damon_report_queue.reports; > > } > > > > static int __init damon_init(void) > > @@ -4319,6 +4338,14 @@ static int __init damon_init(void) > > return -ENOMEM; > > } > > > > + damon_report_queue.size = 1000; > > + damon_report_queue.reports = kmalloc_objs(*damon_report_queue.reports, > > + 1000, GFP_KERNEL); > > + if (!damon_report_queue.reports) { > > + pr_err("report queue alloc fail\n"); > > + return -ENOMEM; > > + } > > [Severity: Medium] > Does this error path leak damon_region_cache when kmalloc_objs() fails? > Destroying damon_region_cache and resetting it (along with > damon_report_queue.size) before returning -ENOMEM would avoid leaking the > slab cache and leaving partially initialized state. Good suggestion. I will do destroy damon_region_cache. > > -- > Sashiko AI review ยท https://sashiko.dev/#/patchset/20261115202849.99134-1-sj@kernel.org?part=2 > Thanks, SJ