From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E9A0C3DA6E for ; Wed, 20 Dec 2023 19:59:50 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8FB2A6B0074; Wed, 20 Dec 2023 14:59:49 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8AB2F6B0075; Wed, 20 Dec 2023 14:59:49 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 79AA06B0078; Wed, 20 Dec 2023 14:59:49 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 6D5B56B0074 for ; Wed, 20 Dec 2023 14:59:49 -0500 (EST) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 45C57405A9 for ; Wed, 20 Dec 2023 19:59:49 +0000 (UTC) X-FDA: 81588262098.18.BF6DE72 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf09.hostedemail.com (Postfix) with ESMTP id A3C6814001A for ; Wed, 20 Dec 2023 19:59:45 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=nGclzkJI; dmarc=none; spf=none (imf09.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1703102386; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=MOQBkuV64qGkpkL02M2q/zJVUfocblbpJ8/Q7Pg5Jnc=; b=3ZJtPl1d8jMV15hhOIuAfQNvcyNPvASh0vqClmjTaKKcGV6+9cd3lSLFJ/XDfqMnAcYSrq oJhq2OfDMDaLYn7RBumFoUpUP8HWgaf079mrFCyDdo2o4gzH4o/wNFWb+8dGqYVkJ7Nhmw QebTxFtYijUttLAGXFK8vBJ7mYkGUKs= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=nGclzkJI; dmarc=none; spf=none (imf09.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1703102386; a=rsa-sha256; cv=none; b=6qQq2tAUYXp0PXW0qNZaMr90LVg1k6x/ghutJaKM6CeKDHaZtc0kmCZ86IzWstdTR/vcgE DAytD355SaPXTYVCT9k9DSIU1lHgyHwRAG4IXpw4s5toGCz0EKuCrWRvoGpudxjL6y2DAR ySrfq4OQUQr8Nc3lztDc5kbW4kWTUgM= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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; bh=MOQBkuV64qGkpkL02M2q/zJVUfocblbpJ8/Q7Pg5Jnc=; b=nGclzkJI27pB0hdUSS5ouVV0ns O+02D269IBZ8f7WlDkCx6o7vRlP+AcWviiCSxE9Xn4rqSC7fubqVL0J6J8yG5tGrmbJ3/Entj/RgB xusZ7QrgCc32vwQkLV6HTKigjopb1NrrsKiTqUWMEj6Nf+C4zN67FkXhaIRiSK5jvbuAM8rgKUs3o +n1Ci83at1FkOal+kmoinH8t2A8APDD2M8TWwT6abZIKSIqNnwBdUseorZuM09PWH+CT/QsUsb5Zv 7rFdrklOtINI2fyQJ4jHkCXqYs5hWiSrk8gGFKfOyIpg2nCa3rPwY+O2goOf39CGNWUvDcaVEGbSd pYNwbF1w==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1rG2io-004Imu-0V; Wed, 20 Dec 2023 19:59:14 +0000 Date: Wed, 20 Dec 2023 19:59:13 +0000 From: Matthew Wilcox To: Ira Weiny Cc: "Fabio M. De Francesco" , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/memory: Replace kmap() with kmap_local_page() Message-ID: References: <20231215084417.2002370-1-fabio.maria.de.francesco@linux.intel.com> <657fbdb5db945_126a129483@iweiny-mobl.notmuch> <4255260.irdbgypaU6@fdefranc-mobl3> <6583463e8de5c_30a94294fb@iweiny-mobl.notmuch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6583463e8de5c_30a94294fb@iweiny-mobl.notmuch> X-Rspamd-Queue-Id: A3C6814001A X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: 31h9fbf9sqwptzua169tdnm59sr4hzcc X-HE-Tag: 1703102385-545614 X-HE-Meta: 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 BUuOKA/A koJNLQ9IWIXQltGGnRXyHua9k5Xnl6K6bkkldkuGfT7uSAErW/Posdd7SVkp1NhQNdPpf7b/uu+l8UkHGi4vEQD5BYbALSJ1Vr3Ug+NiGjDb5W2ConsimqtrGSeiy4yo+ivpjRwCupaHXj00WkcSofcXBG+gcx7yfe8N34+OuwONKU75fA0Hph2IPSw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Dec 20, 2023 at 11:53:34AM -0800, Ira Weiny wrote: > > My understanding of the current implementation is that unmap_and_put_page() > > calls folio_release_kmap(), taking as arguments the folio which the page > > belongs to and the kernel virtual address returned by kmap_local_page(). > > > > folio_release_kmap() calls kunmap_local() and then folio_put(). The last is > > called on the folio obtained by the unmap_and_put_page() wrapper and, if I'm > > not wrong, it releases refcounts on folios like put_page() does on pages. > > This is where my consternation came from. I saw the folio_put() and did > not realize that get_page() now calls folio_get(). That's not new. See 86d234cb0499 which changed get_page() to call folio_get(), but notice that it's doing the _exact same thing_ that get_page() used to do. And it's behaved this way since ddc58f27f9ee in 2016.