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 X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB619C28CBC for ; Mon, 4 May 2020 03:10:38 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6A7DF20643 for ; Mon, 4 May 2020 03:10:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="g1BP8fSK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6A7DF20643 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 167E88E0005; Sun, 3 May 2020 23:10:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0F15D8E0001; Sun, 3 May 2020 23:10:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0077B8E0005; Sun, 3 May 2020 23:10:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0238.hostedemail.com [216.40.44.238]) by kanga.kvack.org (Postfix) with ESMTP id D88D38E0001 for ; Sun, 3 May 2020 23:10:37 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 94385181AEF0B for ; Mon, 4 May 2020 03:10:37 +0000 (UTC) X-FDA: 76777558914.09.rat60_79d54f9ad2414 X-HE-Tag: rat60_79d54f9ad2414 X-Filterd-Recvd-Size: 2293 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf22.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 May 2020 03:10:37 +0000 (UTC) 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; bh=XXJ2nLBUwta0Na249+bQSZuRqkr1ECfsOkPvLduFZV0=; b=g1BP8fSKFiDU9E9Y5b2D0PjBQ9 FiTM+ywvRARjPcGKha2iPGb2jDEvx4LVKONbuyki4+x71gAasA27cT0q7u8QoYcB0MwlN7ERRAJjr WKLnPLVnRh/Vvm8n2lv8RnuZh4WkFYGYhZWt3YjYZtfWynEsbpCZN6eCn6dRZngWoeKtGfdtJ+EQq SOqybcna34WTXu2+HnuBtfRdxEUnJteMRxhaUazWMbKkOkkV0aX4akfdTLlkJF3tVZprTnXy+OUKw 8LXH5a3Mb5pTkOQv29D2dUwD64tkrWPqnWEtXX81TQDDdXOhEefvUS1+BM0OuXD8ViENU2E8FosH7 tmjJOBBw==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jVRV6-0000DP-89; Mon, 04 May 2020 03:10:36 +0000 Date: Sun, 3 May 2020 20:10:36 -0700 From: Matthew Wilcox To: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 18/25] mm: Allow large pages to be added to the page cache Message-ID: <20200504031036.GB16070@bombadil.infradead.org> References: <20200429133657.22632-1-willy@infradead.org> <20200429133657.22632-19-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200429133657.22632-19-willy@infradead.org> 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: On Wed, Apr 29, 2020 at 06:36:50AM -0700, Matthew Wilcox wrote: > @@ -886,7 +906,7 @@ static int __add_to_page_cache_locked(struct page *page, > /* Leave page->index set: truncation relies upon it */ > if (!huge) > mem_cgroup_cancel_charge(page, memcg, false); > - put_page(page); > + page_ref_sub(page, nr); > return xas_error(&xas); > } > ALLOW_ERROR_INJECTION(__add_to_page_cache_locked, ERRNO); This is wrong. page_ref_sub() will not call __put_page() if the refcount gets to zero. What do people prefer? - put_page(page); (a) + put_thp(page); (b) + put_page_nr(page, nr); (c) + if (page_ref_sub_return(page, nr) == 0) + __put_page(page);