From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-180.mta1.migadu.com (out-180.mta1.migadu.com [95.215.58.180]) (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 AB664420E6A for ; Mon, 13 Jul 2026 13:13:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783948385; cv=none; b=Jvk6wP6brGaadS9tGI64NaxATERZEYMP2aev1vpcsgBMeHsWqrpiyii8KJrLzhmXXMHu4GO+V9ZFQux0NyIF02JrxjfEWLgl3IFEuepd0h04fZM8ZNYiDMZwhXvEAjuyp0A8zd30FSrzeThAgWNYNpkAgiecEV7+twO4x/e+NkU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783948385; c=relaxed/simple; bh=BgJBPkZ5skj/gjGlTheMmG+N99+EZQjf1oVIDsBj5d8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=jgh75n+6yk51UEyzjFO0AAy4rSSlUL1pSso4UK1NYemhToZAvkfGWvKFY/t/x2QESHy7+pxhMJE6Kd90kn0qiWZs2g5ts3ugDl0SbkogIwR+j9qm/sePhT94YcEGvQWzmYp8ftHihcgIRl7X2KWEAuyD8zBPr8Iah1eSXmQDBGk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=fM+mafjp; arc=none smtp.client-ip=95.215.58.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="fM+mafjp" Message-ID: <4752c658-7b61-4636-ab5b-bd172e11a42c@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1783948371; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BgJBPkZ5skj/gjGlTheMmG+N99+EZQjf1oVIDsBj5d8=; b=fM+mafjpFjm2q6euqpTOUH9LBCGN2HTwkh1zBOC+/9y7KBmXmgV17ArNOvAO6G6YmjYHgO Jwwvr/aJHS5zV0U9Zutr3M7/9j4zoA0CcmISGvtC4uhCqDYWybCjWX+bfKh5IYeNdSuJ6I dls6V2uYq0RaU21yrr4lRHFpoe4Oa7Y= Date: Mon, 13 Jul 2026 21:12:38 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH] fs/super: skip non-memcg-aware nr_cached_objects in memcg slab shrink To: Usama Arif , brauner@kernel.org, jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Al Viro , linux-mm@kvack.org Cc: hughd@google.com, boris@bur.io, clm@fb.com, dsterba@suse.com, linux-btrfs@vger.kernel.org, cem@kernel.org, linux-xfs@vger.kernel.org, shakeel.butt@linux.dev, hannes@cmpxchg.org, riel@surriel.com, kernel-team@meta.com References: <20260609123047.1948242-1-usama.arif@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Qi Zheng In-Reply-To: <20260609123047.1948242-1-usama.arif@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT Hi Usama, On 6/9/26 8:30 PM, Usama Arif wrote: > The super_block shrinker is registered with SHRINKER_MEMCG_AWARE because its > dentry and inode LRUs are memcg-aware (via list_lru). But the optional > ->nr_cached_objects() hooks that the shrinker also drives are not memcg-aware: > btrfs extent maps and xfs inode reclaim operate on filesystem-global > state, and shmem's unused-huge shrinker walks a per-superblock shrinklist. > None of them filter by sc->memcg. This makes sense for now, but how should we handle this if these shrinkers are made memcg-aware in the future? I've recently been working on making the shmem huge shrinker memcg-aware, but noticed my changes broke after rebasing onto the latest tree, which led me to this patch. As for the shmem huge shrinker, I can work around this limitation by making it a separate shrinker. But this feels more like an overall design decision, effectively meaning that all nr_cached_objects are precluded from being memcg-aware. Thanks, Qi