From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) (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 A1FA831619B for ; Wed, 1 Apr 2026 14:47:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=82.195.75.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775054855; cv=none; b=PQY2QznutDBHd4u+BKn5Z+VXHxzaeAByHsjCLMdPvht2RkM0Zamf8iS6OQJxbmbhVGL94znGS+mnjZTG93tMKgWRV183N305lFFTm8zSeLKIr3UVSVSVI9PnD2Objn4G/qWNRDLQ79WD02zR8YIWUAaaorwm38UQwqoEy4+i89I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775054855; c=relaxed/simple; bh=1cDwOrZIUkhMQhXGaX5gnRqlfv09oXKsX7tl9oA8qtw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MaNyFyLiWRet4Uo0WnBM2jgB8VO+3Gzjk7aVXtmQtIK0N4i6WnF3u+BnZCDtT1qY69bI9RWtKZpSpyeiR8az1ZFfn67Vx8aG50Btllaiw+hvzwp340nN4k11kwYZcx2+Su6rVXqrX5nTuuTThKz6Va7Hrctt3i8OXO+9+7QhE9g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=debian.org; spf=none smtp.mailfrom=debian.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b=fVUZv9jc; arc=none smtp.client-ip=82.195.75.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=debian.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b="fVUZv9jc" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=JnSPjif5Uaj42mJ9z9PRSlAuR5srdE7KzJ1Mpd5Z4zI=; b=fVUZv9jcUfB/+Op9gRasnSrFPu 6a55c6PQIdS4o+sRVJ44OSIe6NEBgl2Dxj212AginiEqdcHZl1MUBwBU3dp4ihAqiZ5eKYISW2P6K rdLdgS9PxeQmrrtHBsmT6X+nZSgPYzJO7XwbZIixn/t822yrTmejacHJgqx1eKrOAkSNOdJPQT57W SNrAWjQ96b05a05NWrM+UtkvE1sJvNPFbap13V0thSO2/GKzgziT0GlJ3Xd8ycNFGUNR7Ce0CY5MH CI6/2U9WfkXRFvRLXKOI8En37s4QBbs+lVECDXvpbUPf/lneU6DiWjiaeWiOb5ZhE6zq6bCGCaezZ CDjjEfOg==; Received: from authenticated user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1w7wqs-0033kT-23; Wed, 01 Apr 2026 14:47:25 +0000 Date: Wed, 1 Apr 2026 07:47:19 -0700 From: Breno Leitao To: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kas@kernel.org, shakeel.butt@linux.dev, usama.arif@linux.dev, kernel-team@meta.com Subject: Re: [PATCH] mm/vmstat: spread vmstat_update requeue across the stat interval Message-ID: References: <20260401-vmstat-v1-1-b68ce4a35055@debian.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260401-vmstat-v1-1-b68ce4a35055@debian.org> X-Debian-User: leitao On Wed, Apr 01, 2026 at 06:57:50AM -0700, Breno Leitao wrote: > free_pcppages_bulk contention (KASAN): > +--------------+----------+----------+ > | Metric | No fix | With fix | > +--------------+----------+----------+ > | Contentions | 872 | 117 | > | Total wait | 199.43ms | 80.76ms | > | Max wait | 4.19ms | 35.76ms | > +--------------+----------+----------+ > > Results without KASAN: > > free_pcppages_bulk contention (no KASAN): > +--------------+----------+----------+ > | Metric | No fix | With fix | > +--------------+----------+----------+ > | Contentions | 240 | 133 | > | Total wait | 34.01ms | 24.61ms | > | Max wait | 965us | 1.35ms | > +--------------+----------+----------+ Sorry, the Max wait time is inverted on both cases. free_pcppages_bulk contention (KASAN): +--------------+----------+----------+ | Metric | No fix | With fix | +--------------+----------+----------+ | Contentions | 872 | 117 | | Total wait | 199.43ms | 80.76ms | | Max wait | 35.76ms | 4.19ms | +--------------+----------+----------+ Results without KASAN: free_pcppages_bulk contention (no KASAN): +--------------+----------+----------+ | Metric | No fix | With fix | +--------------+----------+----------+ | Contentions | 240 | 133 | | Total wait | 34.01ms | 24.61ms | | Max wait | 1.35ms | 965us | +--------------+----------+----------+