From patchwork Wed Mar 6 10:41:35 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 13583887 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F18C9C5475B for ; Wed, 6 Mar 2024 10:42:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=e8NcSXQ/MIdi9de60HY882JCBIIVfzx2lrIdgZUVbHo=; b=o9HyN3fivpWofQ RiGySCWcnhWgE6HImCCoYnATFfBab7SE3pGeqrHdDrLZwTOAkSfNM9+rH5MmjDpW5kPDCe69p1hQ2 fp6bcqrj+FLi6smwjAMaNazmIx8l9eRnC7QBj+FSJ9bvd6+vhZ4xWbVp1mkmOvZnFfHQIQm4y0KbH VA5zAyHXvuLrCeptl8t82akSZoHOrZWnYVnXuA7iE52ZIzlEpLBvXXQ2e6KN5TdiROWN4Xn4SxhBT eod3vcgQDg28v7Jluo0jKD7/pggedGm4YqCfAevi50yUPZmpEEBrzG6Eaix06uY0Pmoo5o6sXWZug NvAu4B2KAx3COd5xiiuQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rhoiz-0000000HSjV-1tch; Wed, 06 Mar 2024 10:42:13 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rhoiw-0000000HSgc-1V63 for linux-arm-kernel@lists.infradead.org; Wed, 06 Mar 2024 10:42:11 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1709721728; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=20nNimBrOEQv87l0vyMx8t0O66X6ZMzRQtOERvnhrUo=; b=cLeURglkwkRzHo8oQ5I3fyDGuW7soNfjQWd8FO14Gca63TxWBsBfKUXoeNk6uUFKhuig6J utyBNIGWl97HCI5HYGSN6OR/vaZqghgo61+6h6JrAfj6zqwxRWTxoki23LtIpNvtX4IsBW 6LOnPn6qrQP8c+4PwT2qojIuuFrMIdc= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-651-oo52lPpuOsCDdbHCtpeneA-1; Wed, 06 Mar 2024 05:42:04 -0500 X-MC-Unique: oo52lPpuOsCDdbHCtpeneA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C7D471C05AF3; Wed, 6 Mar 2024 10:42:03 +0000 (UTC) Received: from x1n.redhat.com (unknown [10.72.116.8]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3C2C5112131D; Wed, 6 Mar 2024 10:41:56 +0000 (UTC) From: peterx@redhat.com To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org, Andrew Morton , Muchun Song , Jason Gunthorpe , peterx@redhat.com, Matthew Wilcox , Mike Rapoport , Christophe Leroy , x86@kernel.org, sparclinux@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Alistair Popple Subject: [PATCH RFC 01/13] mm/hmm: Process pud swap entry without pud_huge() Date: Wed, 6 Mar 2024 18:41:35 +0800 Message-ID: <20240306104147.193052-2-peterx@redhat.com> In-Reply-To: <20240306104147.193052-1-peterx@redhat.com> References: <20240306104147.193052-1-peterx@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240306_024210_655009_A4E85788 X-CRM114-Status: GOOD ( 13.87 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Peter Xu Swap pud entries do not always return true for pud_huge() for all archs. x86 and sparc (so far) allow it, but all the rest do not accept a swap entry to be reported as pud_huge(). So it's not safe to check swap entries within pud_huge(). Check swap entries before pud_huge(), so it should be always safe. This is the only place in the kernel that (IMHO, wrongly) relies on pud_huge() to return true on pud swap entries. The plan is to cleanup pXd_huge() to only report non-swap mappings for all archs. Cc: Alistair Popple Signed-off-by: Peter Xu Reviewed-by: Jason Gunthorpe --- mm/hmm.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/mm/hmm.c b/mm/hmm.c index 277ddcab4947..c44391a0246e 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -424,7 +424,7 @@ static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end, walk->action = ACTION_CONTINUE; pud = READ_ONCE(*pudp); - if (pud_none(pud)) { + if (pud_none(pud) || !pud_present(pud)) { spin_unlock(ptl); return hmm_vma_walk_hole(start, end, -1, walk); } @@ -435,11 +435,6 @@ static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end, unsigned long *hmm_pfns; unsigned long cpu_flags; - if (!pud_present(pud)) { - spin_unlock(ptl); - return hmm_vma_walk_hole(start, end, -1, walk); - } - i = (addr - range->start) >> PAGE_SHIFT; npages = (end - addr) >> PAGE_SHIFT; hmm_pfns = &range->hmm_pfns[i];