Linux-mm Archive on lore.kernel.org
 help / color / Atom feed
From: Michal Hocko <mhocko@kernel.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Stable tree <stable@vger.kernel.org>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jan Kara <jack@suse.cz>
Subject: Re: [Stable 4.4 - NEEDS REVIEW - 2/3] mm: filemap: don't plant shadow entries without radix tree node
Date: Mon, 24 Oct 2016 21:08:17 +0200
Message-ID: <20161024190816.GE13148@dhcp22.suse.cz> (raw)
In-Reply-To: <20161024185600.GB28326@cmpxchg.org>

On Mon 24-10-16 14:56:00, Johannes Weiner wrote:
> Hi Michal,
> 
> On Mon, Oct 24, 2016 at 05:26:04PM +0200, Michal Hocko wrote:
> > @@ -155,44 +155,27 @@ static void page_cache_tree_delete(struct address_space *mapping,
> >  				   struct page *page, void *shadow)
> >  {
> >  	struct radix_tree_node *node;
> > -	unsigned long index;
> > -	unsigned int offset;
> > -	unsigned int tag;
> >  	void **slot;
> >  
> >  	VM_BUG_ON(!PageLocked(page));
> >  
> >  	__radix_tree_lookup(&mapping->page_tree, page->index, &node, &slot);
> >  
> > -	if (shadow) {
> > -		mapping->nrshadows++;
> > -		/*
> > -		 * Make sure the nrshadows update is committed before
> > -		 * the nrpages update so that final truncate racing
> > -		 * with reclaim does not see both counters 0 at the
> > -		 * same time and miss a shadow entry.
> > -		 */
> > -		smp_wmb();
> > -	}
> > -	mapping->nrpages--;
> > +	radix_tree_clear_tags(&mapping->page_tree, node, slot);
> >  
> >  	if (!node) {
> > -		/* Clear direct pointer tags in root node */
> > -		mapping->page_tree.gfp_mask &= __GFP_BITS_MASK;
> > -		radix_tree_replace_slot(slot, shadow);
> > -		return;
> > -	}
> 
> There is no need to include the refactoring of the tag clearing in the
> stable backport. I already sent a simpler backport of this patch for
> 4.4 to Greg, attached here for reference:

I do not see this in 4.4 so maybe it's fallen through cracks. Yours
definitely looks easier and I will use it. I will post all 4 patches for
inclusion for stable tomorrow unless something else pops out.

Thanks for the review again!
-- 
Michal Hocko
SUSE Labs

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  reply index

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-24 15:26 [Stable 4.4 - NEEDS REVIEW - 0/3] mm: working set fixes Michal Hocko
2016-10-24 15:26 ` [Stable 4.4 - NEEDS REVIEW - 1/3] mm: workingset: fix crash in shadow node shrinker caused by replace_page_cache_page() Michal Hocko
2016-10-24 18:52   ` Johannes Weiner
2016-10-24 18:58     ` Michal Hocko
2016-10-24 15:26 ` [Stable 4.4 - NEEDS REVIEW - 2/3] mm: filemap: don't plant shadow entries without radix tree node Michal Hocko
2016-10-24 18:56   ` Johannes Weiner
2016-10-24 19:08     ` Michal Hocko [this message]
2016-10-24 15:26 ` [Stable 4.4 - NEEDS REVIEW - 3/3] mm: filemap: fix mapping->nrpages double accounting in fuse Michal Hocko
2016-10-24 18:56   ` Johannes Weiner

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=20161024190816.GE13148@dhcp22.suse.cz \
    --to=mhocko@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=hannes@cmpxchg.org \
    --cc=jack@suse.cz \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=stable@vger.kernel.org \
    --cc=torvalds@linux-foundation.org \
    /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

Linux-mm Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-mm/0 linux-mm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-mm linux-mm/ https://lore.kernel.org/linux-mm \
		linux-mm@kvack.org
	public-inbox-index linux-mm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kvack.linux-mm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git