LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Andrew Morton <akpm@linux-foundation.org>
To: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Hugh Dickins <hugh@veritas.com>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Linux Memory Management <linux-mm@kvack.org>,
	Linux Filesystems <linux-fsdevel@vger.kernel.org>
Subject: Re: [patch 1/3] mm: fix PageUptodate memorder
Date: Tue, 6 Feb 2007 00:25:12 -0800	[thread overview]
Message-ID: <20070206002512.4e0bbbad.akpm@linux-foundation.org> (raw)
In-Reply-To: <20070206054935.21042.13541.sendpatchset@linux.site>

On Tue,  6 Feb 2007 09:02:11 +0100 (CET) Nick Piggin <npiggin@suse.de> wrote:

> +static inline void __SetPageUptodate(struct page *page)
> +{
> +#ifdef CONFIG_S390
>  	if (!test_and_set_bit(PG_uptodate, &page->flags))
>  		page_test_and_clear_dirty(page);
> -}
>  #else
> -#define SetPageUptodate(page)	set_bit(PG_uptodate, &(page)->flags)
> +	/*
> +	 * Memory barrier must be issued before setting the PG_uptodate bit,
> +	 * so all previous writes that served to bring the page uptodate are
> +	 * visible before PageUptodate becomes true.
> +	 *
> +	 * S390 is guaranteed to have a barrier in the test_and_set operation
> +	 * (see Documentation/atomic_ops.txt).
> +	 *
> +	 * XXX: does this memory barrier need to be anything special to
> +	 * handle things like DMA writes into the page?
> +	 */
> +	smp_wmb();
> +	set_bit(PG_uptodate, &(page)->flags);
>  #endif
> +}
> +
> +static inline void SetPageUptodate(struct page *page)
> +{
> +	WARN_ON(!PageLocked(page));
> +	__SetPageUptodate(page);
> +}
> +
> +static inline void SetNewPageUptodate(struct page *page)
> +{
> +	__SetPageUptodate(page);
> +}

I was panicing for a minute when I saw that __SetPageUptodate() in there.

Conventionally the __SetPageFoo namespace is for nonatomic updates to
page->flags.  Can we call this something different?


What a fugly patchset :(

  reply	other threads:[~2007-02-06  8:25 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-06  8:02 [patch 0/3] 2.6.20 fix for PageUptodate memorder problem Nick Piggin
2007-02-06  8:02 ` [patch 1/3] mm: fix PageUptodate memorder Nick Piggin
2007-02-06  8:25   ` Andrew Morton [this message]
2007-02-06  8:51     ` Nick Piggin
2007-02-06  8:02 ` [patch 2/3] fs: buffer don't PageUptodate without page locked Nick Piggin
2007-02-06  8:21   ` Andrew Morton
2007-02-06  8:31     ` Nick Piggin
2007-02-06  8:02 ` [patch 3/3] mm: make read_cache_page synchronous Nick Piggin
2007-02-06  8:28   ` Andrew Morton
2007-02-06  8:56     ` Nick Piggin
2007-02-06  8:58     ` Nick Piggin
2007-02-06 22:58 ` [patch 0/3] 2.6.20 fix for PageUptodate memorder problem David Chinner
2007-02-07  3:13   ` Nick Piggin
2007-02-08 13:26 [patch 0/3] 2.6.20 fix for PageUptodate memorder problem (try 2) Nick Piggin
2007-02-08 13:27 ` [patch 1/3] mm: fix PageUptodate memorder Nick Piggin

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20070206002512.4e0bbbad.akpm@linux-foundation.org \
    --to=akpm@linux-foundation.org \
    --cc=hugh@veritas.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=npiggin@suse.de \
    --cc=torvalds@linux-foundation.org \
    --subject='Re: [patch 1/3] mm: fix PageUptodate memorder' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).