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 DC0893BED0C for ; Tue, 2 Jun 2026 22:26:52 +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=1780439214; cv=none; b=NBJlGxHkCyya7nG5/TVs9l+mGhNKpSduVsYWUzN9+vXqcjsBOZZO1SvaH+DIBHIXHU1IPsCpKool7Zl2p9std+JzG5qYYEBvr06zGKh9pvogVd3hYSJallRHRr5oK6th6qk88F11Y2NTuFmoRx2dFNXRnLDNtkeP04PeUgEJryk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780439214; c=relaxed/simple; bh=z2GRFIJDLUs0zqghpXpvcmtx+2RFU2K+SgawPMD8KNA=; h=Date:To:From:Subject:Message-Id; b=kdrVkRowVLJg2odm4MrXHNWYHQRYcou8mVbWKW+etcruZAZd+Rrl2IQVqBlEqkPAJZyeabYaumHDtE0MCi+bmgcKiIVYaScFfwfR55RbgYcvDLYMOT2NglXEMB3tBA/HQ25ItMBVPbrtNHH7xFcHsqke3XOdBRaIQWPXQKZu7O0= 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=ME4ny4mQ; 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="ME4ny4mQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF1BC1F00893; Tue, 2 Jun 2026 22:26:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1780439212; bh=51Z6DTa185B7N84kqX6bV6Fc6Cenpbhjr2IYY27rubU=; h=Date:To:From:Subject; b=ME4ny4mQpKvaj8+dJ9Wvs5tocIdo0AzLDNDWk7DFMXducm440SorQTnd7TKATKA/9 thop0ZZ+r2B2gKjJgN+7zvH3s7VnenhsMwSFxSQXYL5jxwB07J5DE5GUUCNQPeHnDY DaSQuSJpgBAuKu6R8sAsVZ3n1YlbOI1L5iyyVb5o= Date: Tue, 02 Jun 2026 15:26:52 -0700 To: mm-commits@vger.kernel.org,roman.gushchin@linux.dev,qi.zheng@linux.dev,oliver.sang@intel.com,muchun.song@linux.dev,mhocko@kernel.org,joshua.hahnjy@gmail.com,harry@kernel.org,hannes@cmpxchg.org,alex@ghiti.fr,shakeel.butt@linux.dev,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] memcg-int16_t-for-cached-slab-stats.patch removed from -mm tree Message-Id: <20260602222652.AF1BC1F00893@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: memcg: int16_t for cached slab stats has been removed from the -mm tree. Its filename was memcg-int16_t-for-cached-slab-stats.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Shakeel Butt Subject: memcg: int16_t for cached slab stats Date: Mon, 25 May 2026 20:39:30 -0700 Currently struct obj_stock_pcp stores cached slab stats in 'int' which is 4 bytes per counter on 64-bit machines. Switch them to int16_t to shrink the cached metadata. The existing PAGE_SIZE flush in __account_obj_stock() bounds *bytes at PAGE_SIZE on 4KiB and 16KiB page archs, well within int16_t. On 64KiB pages PAGE_SIZE is well above S16_MAX so that flush never fires, and a sufficiently long run of accumulations would overflow the cache. Add an explicit S16_MAX guard before each add: when the next add would push abs(*bytes) past S16_MAX, fold the cached value into @nr and flush directly via mod_objcg_mlstate() before the accumulation. Link: https://lore.kernel.org/20260526033931.1760588-4-shakeel.butt@linux.dev Fixes: 01b9da291c49 ("mm: memcontrol: convert objcg to be per-memcg per-node type") Signed-off-by: Shakeel Butt Tested-by: kernel test robot Reviewed-by: Harry Yoo (Oracle) Acked-by: Qi Zheng Acked-by: Muchun Song Cc: Alexandre Ghiti Cc: Johannes Weiner Cc: Joshua Hahn Cc: Michal Hocko Cc: Roman Gushchin Signed-off-by: Andrew Morton --- mm/memcontrol.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) --- a/mm/memcontrol.c~memcg-int16_t-for-cached-slab-stats +++ a/mm/memcontrol.c @@ -2032,8 +2032,8 @@ struct obj_stock_pcp { uint16_t nr_bytes; #endif int16_t node_id; - int nr_slab_reclaimable_b; - int nr_slab_unreclaimable_b; + int16_t nr_slab_reclaimable_b; + int16_t nr_slab_unreclaimable_b; struct work_struct work; unsigned long flags; @@ -3170,7 +3170,7 @@ static void __account_obj_stock(struct o struct obj_stock_pcp *stock, int nr, struct pglist_data *pgdat, enum node_stat_item idx) { - int *bytes; + int16_t *bytes; /* * Though at the moment MAX_NUMNODES <= 1024 in all archs but let's make @@ -3207,21 +3207,20 @@ static void __account_obj_stock(struct o bytes = (idx == NR_SLAB_RECLAIMABLE_B) ? &stock->nr_slab_reclaimable_b : &stock->nr_slab_unreclaimable_b; + /* - * Even for large object >= PAGE_SIZE, the vmstat data will still be - * cached locally at least once before pushing it out. + * Fold @nr into the cached value and decide whether to keep it cached + * or flush it directly. Cache the combined value when it fits in the + * int16_t storage and either the cache was empty (so even a value + * above PAGE_SIZE gets a chance to be canceled by a paired delta) or + * the combined value is within the PAGE_SIZE flush threshold. */ - if (!*bytes) { + nr += *bytes; + if (abs(nr) <= S16_MAX && (!*bytes || abs(nr) <= PAGE_SIZE)) { *bytes = nr; nr = 0; } else { - *bytes += nr; - if (abs(*bytes) > PAGE_SIZE) { - nr = *bytes; - *bytes = 0; - } else { - nr = 0; - } + *bytes = 0; } direct: if (nr) _ Patches currently in -mm which might be from shakeel.butt@linux.dev are mm-list_lru-drain-before-clearing-xarray-entry-on-reparent.patch