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 BCC6A42078 for ; Thu, 2 May 2024 15:35:50 +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=1714664150; cv=none; b=FijaFsN9FQsCIOZc9PRWY1NcAdxZqBtg5hS5DwzP53LgMXUDziP+DV0IEjqWx+inNVjO3c9sEFeiUJHDLCkgHD39CFLQ+RLtFK1rwdwN4bo40rFEYgqGTPuUYaZwYJdYhH3gciwA9mmE+/8chTGv2lEKe397qJIZ2mSuwKpzvX8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714664150; c=relaxed/simple; bh=21LZLDGlp/y7vOtp4262+xKtW9DyFN5dWTYeelvEJ1o=; h=Date:To:From:Subject:Message-Id; b=MQtHiBCFakD+7VXeu5+4NoflaiHvaTwXJ6KTa7bPuRzqAMyi7hHkjdEIF7BPg5+eJMP4cptuZhSzIHHPPjmbiWzADz475nVKz341FYnF7Ej4fAU7ewz59lL/qoberQWWb2PUqVn4glBSsaqm3Rb5FrotxSUNjmWfj29+wXh3vP8= 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=meqk5PRP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="meqk5PRP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0334AC113CC; Thu, 2 May 2024 15:35:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1714664150; bh=21LZLDGlp/y7vOtp4262+xKtW9DyFN5dWTYeelvEJ1o=; h=Date:To:From:Subject:From; b=meqk5PRP97zryvaqgE2a1esFhFvO71Jh784Dq5gyjqarlsNP6+tCpdigLo+0fNq14 /M6G/ycNMdjXWqSSQofBB/XYLUCRv32ZAbPLL03ie0c56GmpR393Z0sm72wjs6TL1I 7k3uV50TNJuc25Ml7L78spqGiKdxYtpcmgU8mtTw= Date: Thu, 02 May 2024 08:35:48 -0700 To: mm-commits@vger.kernel.org,yosryahmed@google.com,tjmercier@google.com,roman.gushchin@linux.dev,muchun.song@linux.dev,mhocko@kernel.org,hannes@cmpxchg.org,shakeel.butt@linux.dev,akpm@linux-foundation.org From: Andrew Morton Subject: + memcg-reduce-memory-size-of-mem_cgroup_events_index.patch added to mm-unstable branch Message-Id: <20240502153550.0334AC113CC@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: memcg: reduce memory size of mem_cgroup_events_index has been added to the -mm mm-unstable branch. Its filename is memcg-reduce-memory-size-of-mem_cgroup_events_index.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/memcg-reduce-memory-size-of-mem_cgroup_events_index.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Shakeel Butt Subject: memcg: reduce memory size of mem_cgroup_events_index Date: Wed, 1 May 2024 10:26:10 -0700 Patch series "memcg: reduce memory consumption by memcg stats", v4. Most of the memory overhead of a memcg object is due to memcg stats maintained by the kernel. Since stats updates happen in performance critical codepaths, the stats are maintained per-cpu and numa specific stats are maintained per-node * per-cpu. This drastically increase the overhead on large machines i.e. large of CPUs and multiple numa nodes. This patch series tries to reduce the overhead by at least not allocating the memory for stats which are not memcg specific. This patch (of 8): mem_cgroup_events_index is a translation table to get the right index of the memcg relevant entry for the general vm_event_item. At the moment, it is defined as integer array. However on a typical system the max entry of vm_event_item (NR_VM_EVENT_ITEMS) is 113, so we don't need to use int as storage type of the array. For now just use int8_t as type and add a BUILD_BUG_ON(). Another benefit of this change is that the translation table fits in 2 cachelines while previously it would require 8 cachelines (assuming 64 bytes cacheline). Link: https://lkml.kernel.org/r/20240501172617.678560-1-shakeel.butt@linux.dev Link: https://lkml.kernel.org/r/20240501172617.678560-2-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt Reviewed-by: Roman Gushchin Reviewed-by: Yosry Ahmed Reviewed-by: T.J. Mercier Cc: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Signed-off-by: Andrew Morton --- mm/memcontrol.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/mm/memcontrol.c~memcg-reduce-memory-size-of-mem_cgroup_events_index +++ a/mm/memcontrol.c @@ -606,11 +606,13 @@ static const unsigned int memcg_vm_event }; #define NR_MEMCG_EVENTS ARRAY_SIZE(memcg_vm_event_stat) -static int mem_cgroup_events_index[NR_VM_EVENT_ITEMS] __read_mostly; +static int8_t mem_cgroup_events_index[NR_VM_EVENT_ITEMS] __read_mostly; static void init_memcg_events(void) { - int i; + int8_t i; + + BUILD_BUG_ON(NR_VM_EVENT_ITEMS >= S8_MAX); for (i = 0; i < NR_MEMCG_EVENTS; ++i) mem_cgroup_events_index[memcg_vm_event_stat[i]] = i + 1; _ Patches currently in -mm which might be from shakeel.butt@linux.dev are memcg-simple-cleanup-of-stats-update-functions.patch memcg-reduce-memory-size-of-mem_cgroup_events_index.patch memcg-dynamically-allocate-lruvec_stats.patch memcg-reduce-memory-for-the-lruvec-and-memcg-stats.patch memcg-cleanup-__mod_memcg_lruvec_state.patch mm-cleanup-workingset_nodes-in-workingset.patch memcg-warn-for-unexpected-events-and-stats.patch memcg-use-proper-type-for-mod_memcg_state.patch