On 03/30/2016 10:27 AM, Joonsoo Kim wrote:
On Tue, Mar 29, 2016 at 12:23:13PM -0700, Andrew Morton wrote:
On Tue, 29 Mar 2016 11:27:47 +0200 Vlastimil Babka <[email protected]> wrote:

v2: change more _count usages to _refcount

There's also
Documentation/vm/transhuge.txt talking about ->_count
include/linux/mm.h:      * requires to already have an elevated page->_count.
include/linux/mm_types.h:                        * Keep _count separate from 
slub cmpxchg_double data.
include/linux/mm_types.h:                        * slab_lock but _count is not.
include/linux/pagemap.h: * If the page is free (_count == 0), then _count is 
untouched, and 0
include/linux/pagemap.h: * is returned. Otherwise, _count is incremented by 1 
and 1 is returned.
include/linux/pagemap.h: * this allows allocators to use a synchronize_rcu() to 
stabilize _count.
include/linux/pagemap.h: * Remove-side that cares about stability of _count 
(eg. reclaim) has the
mm/huge_memory.c:        * tail_page->_count is zero and not changing from 
under us. But
mm/huge_memory.c:       /* Prevent deferred_split_scan() touching ->_count */
mm/internal.h: * Turn a non-refcounted page (->_count == 0) into refcounted with
mm/page_alloc.c:                bad_reason = "nonzero _count";
mm/page_alloc.c:                bad_reason = "nonzero _count";
mm/page_alloc.c:                 * because their page->_count is zero at all 
time.
mm/slub.c:       * as page->_count.  If we assign to ->counters directly
mm/slub.c:       * we run the risk of losing updates to page->_count, so
mm/vmscan.c:     * load is not satisfied before that of page->_count.
mm/vmscan.c: * The downside is that we have to touch page->_count against each 
page.

I've arrived at the following command to find this:
git grep "[^a-zA-Z0-9_]_count[^_]"

Not that many false positives in the output :)


From: Andrew Morton <[email protected]>
Subject: mm-rename-_count-field-of-the-struct-page-to-_refcount-fix

fix comments, per Vlastimil

Andrew and Vlastimil, great thanks!

Thanks, Andrew.

That leaves just Documentation/vm/transhuge.txt to you, Joonsoo :)

Thanks.


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