From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 63FED329C48; Sat, 16 May 2026 18:37:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778956646; cv=none; b=gBz7Mswf7irQTD4dLoeWHVKP4rjBMH6DkqeuEwg4+ns4GcJCIrPNnaosAa6nnWNFucdgwCpkXjeefsQIfXR+f2RMuRpBep/5k67fbxN37UIT0AyawHZqXbJEeLG8qIrY4TawoYdMLYXKr0OvWtp4/dbsp08ddm1NIwxu1PCP0sI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778956646; c=relaxed/simple; bh=rRV3S8Zs8/YBc8+5AI5kB/a9fxfrWlXoj5Vu2qtKMvo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iw6ib/RMhfC7MDnmLUACVtGXvBXgGfl0nvwyolW72mVEbFTeKO/VT7E87AIOET2ctHY4wOlyW7XmCHqs/4XAZgKq8dYENGhFI8eJRrJp0hmpmZd8N7KO64+JaGqtI8uECqWpT5NswXfxcv9s2BW93m4BIwcZknZy7pLk7dpYDHY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SK+xuiP4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SK+xuiP4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0F8A6C2BCC7; Sat, 16 May 2026 18:37:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778956646; bh=rRV3S8Zs8/YBc8+5AI5kB/a9fxfrWlXoj5Vu2qtKMvo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SK+xuiP4C2SaxDcfue3JBq/5hYij+Ee22zfOQ6LlqvqDk9kYdu9pGzHSPQTTBbInH lI8AwtBpUNP8Q0J0pMNJecqfzfme9hlNDukGaab3cU/AbSBtk/PsOJshIpPKMV1ltG s2ZhlE2SkmzDXMuWsK73RblUfd4XVDWJ2KEAfoXutOpRNkNuLXi41DA70efNBhp0BV iJzYi8PjHAh8JJ60zu3DmBB4Is+AkFOaFQ4ml1LfexUKjMQYwM2dqol68KXNHR5Tzd VgYjMPTiiFwo02VZz+uGa9qo51mxjy9tBN5v4HMzinTJGVPZ2AVZr4kLktU/0GuCrF GflR/TeenGipw== From: SeongJae Park To: Cc: SeongJae Park , Andrew Morton , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v3 05/28] mm/damon/core: introduce damon_region->probe_hits Date: Sat, 16 May 2026 11:36:46 -0700 Message-ID: <20260516183712.81393-6-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260516183712.81393-1-sj@kernel.org> References: <20260516183712.81393-1-sj@kernel.org> Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add an array for the per-region per-probe positive samples count. For simple and efficient implementation, add a limit to the number of data probes and set the array to support only the limited number of counters. Signed-off-by: SeongJae Park --- include/linux/damon.h | 4 ++++ mm/damon/core.c | 10 ++++++++++ 2 files changed, 14 insertions(+) diff --git a/include/linux/damon.h b/include/linux/damon.h index 32005b8b1f8cd..9e70239e5305f 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -16,6 +16,8 @@ /* Minimal region size. Every damon_region is aligned by this. */ #define DAMON_MIN_REGION_SZ PAGE_SIZE +/* Maximum number of monitoring probes. */ +#define DAMON_MAX_PROBES (4) /* Max priority score for DAMON-based operation schemes */ #define DAMOS_MAX_SCORE (99) @@ -52,6 +54,7 @@ struct damon_size_range { * @nr_accesses: Access frequency of this region. * @nr_accesses_bp: @nr_accesses in basis point (0.01%) that updated for * each sampling interval. + * @probe_hits: Number of probe-positive region samples. * @list: List head for siblings. * @age: Age of this region. * @@ -80,6 +83,7 @@ struct damon_region { unsigned long sampling_addr; unsigned int nr_accesses; unsigned int nr_accesses_bp; + unsigned char probe_hits[DAMON_MAX_PROBES]; struct list_head list; unsigned int age; diff --git a/mm/damon/core.c b/mm/damon/core.c index 15f2795a1156f..e5667660b4cd9 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -225,6 +225,7 @@ static void damon_verify_new_region(unsigned long start, unsigned long end) struct damon_region *damon_new_region(unsigned long start, unsigned long end) { struct damon_region *region; + int i; damon_verify_new_region(start, end); region = kmem_cache_alloc(damon_region_cache, GFP_KERNEL); @@ -235,6 +236,8 @@ struct damon_region *damon_new_region(unsigned long start, unsigned long end) region->ar.end = end; region->nr_accesses = 0; region->nr_accesses_bp = 0; + for (i = 0; i < DAMON_MAX_PROBES; i++) + region->probe_hits[i] = 0; INIT_LIST_HEAD(®ion->list); region->age = 0; @@ -2754,12 +2757,17 @@ static void damon_merge_two_regions(struct damon_target *t, struct damon_region *l, struct damon_region *r) { unsigned long sz_l = damon_sz_region(l), sz_r = damon_sz_region(r); + int i; l->nr_accesses = (l->nr_accesses * sz_l + r->nr_accesses * sz_r) / (sz_l + sz_r); l->nr_accesses_bp = l->nr_accesses * 10000; l->age = (l->age * sz_l + r->age * sz_r) / (sz_l + sz_r); l->ar.end = r->ar.end; + /* todo: do this for only installed probes */ + for (i = 0; i < DAMON_MAX_PROBES; i++) + l->probe_hits[i] = (l->probe_hits[i] * sz_l + r->probe_hits[i] + * sz_r) / (sz_l + sz_r); damon_verify_merge_two_regions(l, r); damon_destroy_region(r, t); } @@ -2882,6 +2890,8 @@ static void damon_split_region_at(struct damon_target *t, new->last_nr_accesses = r->last_nr_accesses; new->nr_accesses_bp = r->nr_accesses_bp; new->nr_accesses = r->nr_accesses; + /* todo: do this for only installed probes */ + memcpy(new->probe_hits, r->probe_hits, sizeof(r->probe_hits)); damon_insert_region(new, r, damon_next_region(r), t); } -- 2.47.3