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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 73989C83007 for ; Wed, 29 Apr 2020 07:34:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4197D206D9 for ; Wed, 29 Apr 2020 07:34:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4197D206D9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-m68k.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B58848E0005; Wed, 29 Apr 2020 03:34:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B09718E0001; Wed, 29 Apr 2020 03:34:15 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A1F028E0005; Wed, 29 Apr 2020 03:34:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0095.hostedemail.com [216.40.44.95]) by kanga.kvack.org (Postfix) with ESMTP id 86CC78E0001 for ; Wed, 29 Apr 2020 03:34:15 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 4D43F2C1F for ; Wed, 29 Apr 2020 07:34:15 +0000 (UTC) X-FDA: 76760079270.17.quiet85_5f50201388140 X-HE-Tag: quiet85_5f50201388140 X-Filterd-Recvd-Size: 3831 Received: from mail-oi1-f194.google.com (mail-oi1-f194.google.com [209.85.167.194]) by imf31.hostedemail.com (Postfix) with ESMTP for ; Wed, 29 Apr 2020 07:34:14 +0000 (UTC) Received: by mail-oi1-f194.google.com with SMTP id 19so961930oiy.8 for ; Wed, 29 Apr 2020 00:34:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=SyWquW6C3h9yYRPnL8ZX6mVqONgOMsOlS/nbLkzCvR8=; b=UZpJJDI25I7EY5xSY5NEfNLYMO4IJekeniGj2yD6E7YjpH3coz82dzLtUCi6ebWHVX J89O6+jvuTn0iwfFBoUk93hEo6+z/FtgFhF4tDEDfyMmjcLyW1CCMXZLrZumwn/+CpwQ l6jXf3thHd30d2O0NHdoJM5gaLDJTXNWCsPv6PI++CdHUa3zZT6SDvSKi80Pl23hZn71 wjkKmQLlQfz58bmqweSAJwRcRCwySIHlb931Mbxuo1pW3PEwo8R7pFdbsLBHA+PAdQul 8AiwEHesmH8VH5a3T4FikP9074lf5E6K3uuEo8geTZjRiWhOoZWlxHxn1F4gSjK5Uqqg l/Sw== X-Gm-Message-State: AGi0PuaPxWTtOzrFsK0cfTYWwUcYjlVuXPDM7WISwqoz9MlJusKTJQwa Afi1AHwGDU3qvngoewaYblipyhgcOZogCf/P420= X-Google-Smtp-Source: APiQypJAsZR6cJVnPhd52DhYQokiZWeX1PxL/6m2Vvtp1dgHuL2QQU2M5utJVEIEaKuPsXF6mplj99rnUrUZngmlKtw= X-Received: by 2002:aca:d50f:: with SMTP id m15mr810760oig.54.1588145654121; Wed, 29 Apr 2020 00:34:14 -0700 (PDT) MIME-Version: 1.0 References: <20200428194449.22615-1-willy@infradead.org> <20200428194449.22615-3-willy@infradead.org> In-Reply-To: <20200428194449.22615-3-willy@infradead.org> From: Geert Uytterhoeven Date: Wed, 29 Apr 2020 09:34:02 +0200 Message-ID: Subject: Re: [PATCH 2/7] mm: Move pt_mm within struct page To: Matthew Wilcox Cc: Linux MM , Linux Kernel Mailing List , Linux ARM , Will Deacon , Catalin Marinas , Russell King , linux-m68k Content-Type: text/plain; charset="UTF-8" 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: Hi Matthew, On Tue, Apr 28, 2020 at 9:44 PM Matthew Wilcox wrote: > From: "Matthew Wilcox (Oracle)" > Instead of a per-arch word within struct page, use a formerly reserved > word. This word is shared with page->mapping, so it must be cleared > before being freed as it is checked in free_pages(). > > Signed-off-by: Matthew Wilcox (Oracle) Thanks for your patch! > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -149,11 +149,8 @@ struct page { > pgtable_t pmd_huge_pte; > }; > }; > - unsigned long _pt_pad_2; /* mapping */ > - union { > - struct mm_struct *pt_mm; /* x86 pgds only */ > - atomic_t pt_frag_refcount; /* powerpc */ > - }; > + struct mm_struct *pt_mm; > + atomic_t pt_frag_refcount; /* powerpc */ So here is now an implicit hole on 64-bit platforms, right? Do we have any where alignof(long) != 8? > #if ALLOC_SPLIT_PTLOCKS > spinlock_t *ptl; > #else Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds