From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Dave Hansen <dave.hansen@intel.com>,
Vlastimil Babka <vbabka@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.cz>,
David Rientjes <rientjes@google.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCH 1/2] zsmalloc: use page->private instead of page->first_page
Date: Thu, 13 Aug 2015 18:54:45 +0300 [thread overview]
Message-ID: <1439481286-81093-2-git-send-email-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <1439481286-81093-1-git-send-email-kirill.shutemov@linux.intel.com>
We are going to rework how compound_head() work. It will not use
page->first_page as we have it now.
The only other user of page->fisrt_page beyond compound pages is
zsmalloc.
Let's use page->private instead of page->first_page here. It occupies
the same storage space.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
mm/zsmalloc.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 0a7f81aa2249..a85754e69879 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -16,7 +16,7 @@
* struct page(s) to form a zspage.
*
* Usage of struct page fields:
- * page->first_page: points to the first component (0-order) page
+ * page->private: points to the first component (0-order) page
* page->index (union with page->freelist): offset of the first object
* starting in this page. For the first page, this is
* always 0, so we use this field (aka freelist) to point
@@ -26,8 +26,7 @@
*
* For _first_ page only:
*
- * page->private (union with page->first_page): refers to the
- * component page after the first page
+ * page->private: refers to the component page after the first page
* If the page is first_page for huge object, it stores handle.
* Look at size_class->huge.
* page->freelist: points to the first free object in zspage.
@@ -770,7 +769,7 @@ static struct page *get_first_page(struct page *page)
if (is_first_page(page))
return page;
else
- return page->first_page;
+ return (struct page *)page_private(page);
}
static struct page *get_next_page(struct page *page)
@@ -955,7 +954,7 @@ static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
* Allocate individual pages and link them together as:
* 1. first page->private = first sub-page
* 2. all sub-pages are linked together using page->lru
- * 3. each sub-page is linked to the first page using page->first_page
+ * 3. each sub-page is linked to the first page using page->private
*
* For each size class, First/Head pages are linked together using
* page->lru. Also, we set PG_private to identify the first page
@@ -980,7 +979,7 @@ static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
if (i == 1)
set_page_private(first_page, (unsigned long)page);
if (i >= 1)
- page->first_page = first_page;
+ set_page_private(first_page, (unsigned long)first_page);
if (i >= 2)
list_add(&page->lru, &prev_page->lru);
if (i == class->pages_per_zspage - 1) /* last page */
--
2.5.0
next prev parent reply other threads:[~2015-08-13 15:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-13 15:54 [PATCH 0/2] Fix compound_head() race Kirill A. Shutemov
2015-08-13 15:54 ` Kirill A. Shutemov [this message]
2015-08-13 15:54 ` [PATCH 2/2] mm: make compound_head() robust Kirill A. Shutemov
2015-08-17 1:40 ` Hugh Dickins
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