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 [thread overview]
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
next prev parent reply other threads:[~2016-10-24 19:10 UTC|newest]
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
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