From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 DC20D146A66; Thu, 27 Aug 2026 05:02:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787806959; cv=none; b=RnwLZPfz7g2xQlUPXaB8D6ECxTuUjwWUGR0nvdFLQuW72eNxDYH/Dr5GsyzmuozLeYW33MvSto2bpMKWbutmXzmkUcYcULy+lXVRFWPnyE0aJj2pD5Wj4QT3V4VAogb93OJGZB9ehTHjc6NSkyjI/mxDBdhNp2cjvG4AxdRqY8k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787806959; c=relaxed/simple; bh=i+wUeZ7MG3m3VkG7W2VNpMGVyi3HjT0iKIkWo7X32lc=; h=Date:To:From:Subject:Message-Id; b=ZmZRYZvZZB1mLBvbb71WfGOzrlJlqlOqSxkW7Ey/aSFwgY+Xtmw81PHY3MU68goc890ycWIDgpfMh3t4SNqyrvwK4dJc4SmUxzu9jtvNrFrs9MnpMXgVUTYJZnr5B887nimFhah4j9o5gvGtVeFIHjcYYUf2K4qevsrC10jSIAA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=ViSiM7Dm; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="ViSiM7Dm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 674031F000E9; Thu, 27 Aug 2026 05:02:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1787806957; bh=n9K6NnDFncTQqWWWL1iB6Yfdc9HxPxQG0Xb1YgqGWgw=; h=Date:To:From:Subject; b=ViSiM7DmBjdt4lz/GUvPtU8zehg/cZrfSBIbAm7oc9bAVez3z60UsHs0i6Hh4isJj B5PDNfidp5iN47DGVwkz7bp3m72tR5MAMiLZISkAnhDYyuSvTNiXxhikMsKQ9IWU/Y eALXtizHlvP2HKeIYdjDax1fgOWosZgYyySBOMmc= Date: Wed, 26 Aug 2026 22:02:36 -0700 To: mm-commits@vger.kernel.org,yanquanmin1@huawei.com,stable@vger.kernel.org,sj@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-damon-core-initialize-damos_quota_goal-last_psi_total.patch removed from -mm tree Message-Id: <20260827050237.674031F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/damon/core: initialize damos_quota_goal->last_psi_total has been removed from the -mm tree. Its filename was mm-damon-core-initialize-damos_quota_goal-last_psi_total.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: SJ Park Subject: mm/damon/core: initialize damos_quota_goal->last_psi_total Date: Wed, 26 Aug 2026 21:29:18 -0700 Patch series "mm/damon: fix wrong behaviors in DAMOS PSI goal and sysfs refresh_ms". PSI based DAMOS auto-tuning and DAMON sysfs refresh_ms file have bugs that can produce non critical but still unexpected behaviors. Fix the two bugs. This patch (of 2): When DAMOS_QUOTA_SOME_MEM_PSI_US metric damos quota goal is set, the PSI delta for the feedback loop is calculated using damos_quota_goal->last_psi_total. However, it is initialized only after the first feedback loop. The first iteration of the loop uses the uninitialized value. As a result, the feedback loop can change the effective quota in an unexpected way at the first iteration. The user impact of the issue is not big, because the issue impacts only the first iteration of the feedback loop. The feedback loop also has an internal cap of the quota adjustment. The wrong adjustment will soon be corrected over a few iterations. For this reason, doing no initialization at commit time was intentional. It is also explicitly commented. That said, nobody likes behaviors that are unexpected or difficult to be expected. Fixing it is also simple and not expensive. Initialize the field at the beginning of kdamond and each commit of SOME_MEM_PSI_US type quota goals. The issue was discovered [1] by Sashiko. Link: https://lore.kernel.org/20260827042920.93580-2-sj@kernel.org Link: https://lore.kernel.org/20260718005316.89585-1-sj@kernel.org [1] Fixes: 2dbb60f789cb ("mm/damon/core: implement PSI metric DAMOS quota goal") Signed-off-by: SJ Park Cc: Quanmin Yan Cc: # 6.9.x Signed-off-by: Andrew Morton --- mm/damon/core.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) --- a/mm/damon/core.c~mm-damon-core-initialize-damos_quota_goal-last_psi_total +++ a/mm/damon/core.c @@ -1122,6 +1122,9 @@ static void damos_commit_quota_goal_unio struct damos_quota_goal *dst, struct damos_quota_goal *src) { switch (dst->metric) { + case DAMOS_QUOTA_SOME_MEM_PSI_US: + dst->last_psi_total = damos_get_some_mem_psi_total(); + break; case DAMOS_QUOTA_NODE_MEM_USED_BP: case DAMOS_QUOTA_NODE_MEM_FREE_BP: dst->nid = src->nid; @@ -1143,7 +1146,6 @@ static void damos_commit_quota_goal( dst->target_value = src->target_value; if (dst->metric == DAMOS_QUOTA_USER_INPUT) dst->current_value = src->current_value; - /* keep last_psi_total as is, since it will be updated in next cycle */ damos_commit_quota_goal_union(dst, src); } @@ -3727,6 +3729,17 @@ static int kdamond_wait_activation(struc return -EBUSY; } +static void damos_init_quota_goal_last_psi(struct damos *s) +{ + struct damos_quota_goal *goal; + + damos_for_each_quota_goal(goal, &s->quota) { + if (goal->metric != DAMOS_QUOTA_SOME_MEM_PSI_US) + continue; + goal->last_psi_total = damos_get_some_mem_psi_total(); + } +} + static void kdamond_init_ctx(struct damon_ctx *ctx) { unsigned long sample_interval = ctx->attrs.sample_interval ? @@ -3743,6 +3756,7 @@ static void kdamond_init_ctx(struct damo damon_for_each_scheme(scheme, ctx) { damos_set_next_apply_sis(scheme, ctx); damos_set_filters_default_reject(scheme); + damos_init_quota_goal_last_psi(scheme); } } _ Patches currently in -mm which might be from sj@kernel.org are mm-damon-sysfs-set-next-refresh-jiffies-per-sysfs-context.patch