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[2607:7c80:54:e::133]) by mx.google.com with ESMTPS id i30si246257pgm.76.2019.02.13.12.26.19 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 13 Feb 2019 12:26:20 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=qGrkOHz8; spf=pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=willy@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=fuyNjv+gA9Cpq0mS7d0DHpZNnRQ2StHPyhGiej79BQg=; b=qGrkOHz8qJCrWPVjL5jQPDQgS USOcI7mUSjEYxD36Eb4n+vEdFCMwhKc4EJKz1DDMC41pa7aa1qsVPetZT1FFYL7dxi59Zx8XHVeC7 KBVChej3yiTi1dXFRaSPrWwsAH0ArhoXNVBYOuMpLzecL25EQ8+dXWQ16KQgwmAghhqaCImMA4giT brascUu2N5+MOPcWY+D4CHjsyvEV39+djsXMMlU3wct/HNkpiV8Nm0xZNzy76PcTGdXKbLDF3oC5P oiLhBL6ZAwgqRj0Fd+WyTLfvmLwgAOPtc+PezbKIGXD92zr0GnfTwRqGcndeHl5GoBs0kp7SzGBl6 VnjE3xRgQ==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1gu16l-0007Kp-LX; Wed, 13 Feb 2019 20:26:16 +0000 Date: Wed, 13 Feb 2019 12:26:15 -0800 From: Matthew Wilcox To: Roman Gushchin Cc: Andrew Morton , Johannes Weiner , Roman Gushchin , "linux-mm@kvack.org" , Kernel Team , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v2 0/3] vmalloc enhancements Message-ID: <20190213202614.GV12668@bombadil.infradead.org> References: <20190212175648.28738-1-guro@fb.com> <20190212184724.GA18339@cmpxchg.org> <20190212123409.7ed5c34d68466dbd8b7013a3@linux-foundation.org> <20190212223605.GA15979@tower.DHCP.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190212223605.GA15979@tower.DHCP.thefacebook.com> User-Agent: Mutt/1.9.2 (2017-12-15) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Feb 12, 2019 at 10:36:12PM +0000, Roman Gushchin wrote: > On Tue, Feb 12, 2019 at 12:34:09PM -0800, Andrew Morton wrote: > > On Tue, 12 Feb 2019 13:47:24 -0500 Johannes Weiner wrote: > > > I don't understand what prompted this change to percpu counters. > > I *think*, I see some performance difference, but it's barely measurable > in my setup. Also as I remember, Matthew was asking why not percpu here. > So if everybody prefers a global atomic, I'm fine with either. I was asking why you were using an accessor instead of a direct reference to the atomic_long_t.