From: Seth Jennings <sjenning@linux.vnet.ibm.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Nitin Gupta <ngupta@vflare.org>, Minchan Kim <minchan@kernel.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Dan Magenheimer <dan.magenheimer@oracle.com>,
Robert Jennings <rcj@linux.vnet.ibm.com>,
Jenifer Hopper <jhopper@us.ibm.com>, Mel Gorman <mgorman@suse.de>,
Johannes Weiner <jweiner@redhat.com>,
Rik van Riel <riel@redhat.com>,
Larry Woodman <lwoodman@redhat.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Dave Hansen <dave@linux.vnet.ibm.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
devel@driverdev.osuosl.org
Subject: [PATCHv4 4/7] mm: break up swap_writepage() for frontswap backends
Date: Tue, 29 Jan 2013 15:40:24 -0600 [thread overview]
Message-ID: <1359495627-30285-5-git-send-email-sjenning@linux.vnet.ibm.com> (raw)
In-Reply-To: <1359495627-30285-1-git-send-email-sjenning@linux.vnet.ibm.com>
swap_writepage() is currently where frontswap hooks into the swap
write path to capture pages with the frontswap_store() function.
However, if a frontswap backend wants to "resume" the writeback of
a page to the swap device, it can't call swap_writepage() as
the page will simply reenter the backend.
This patch separates swap_writepage() into a top and bottom half, the
bottom half named __swap_writepage() to allow a frontswap backend,
like zswap, to resume writeback beyond the frontswap_store() hook.
__add_to_swap_cache() is also made non-static so that the page for
which writeback is to be resumed can be added to the swap cache.
Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Acked-by: Minchan Kim <minchan@kernel.org>
---
include/linux/swap.h | 2 ++
mm/page_io.c | 16 +++++++++++++---
mm/swap_state.c | 2 +-
3 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 68df9c1..fc8920d 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -321,6 +321,7 @@ static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
/* linux/mm/page_io.c */
extern int swap_readpage(struct page *);
extern int swap_writepage(struct page *page, struct writeback_control *wbc);
+extern int __swap_writepage(struct page *page, struct writeback_control *wbc);
extern int swap_set_page_dirty(struct page *page);
extern void end_swap_bio_read(struct bio *bio, int err);
@@ -335,6 +336,7 @@ extern struct address_space swapper_space;
extern void show_swap_cache_info(void);
extern int add_to_swap(struct page *);
extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
+extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
extern void __delete_from_swap_cache(struct page *);
extern void delete_from_swap_cache(struct page *);
extern void free_page_and_swap_cache(struct page *);
diff --git a/mm/page_io.c b/mm/page_io.c
index 78eee32..1cb382d 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -179,15 +179,15 @@ bad_bmap:
goto out;
}
+int __swap_writepage(struct page *page, struct writeback_control *wbc);
+
/*
* We may have stale swap cache pages in memory: notice
* them here and get rid of the unnecessary final write.
*/
int swap_writepage(struct page *page, struct writeback_control *wbc)
{
- struct bio *bio;
- int ret = 0, rw = WRITE;
- struct swap_info_struct *sis = page_swap_info(page);
+ int ret = 0;
if (try_to_free_swap(page)) {
unlock_page(page);
@@ -199,6 +199,16 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
end_page_writeback(page);
goto out;
}
+ ret = __swap_writepage(page, wbc);
+out:
+ return ret;
+}
+
+int __swap_writepage(struct page *page, struct writeback_control *wbc)
+{
+ struct bio *bio;
+ int ret = 0, rw = WRITE;
+ struct swap_info_struct *sis = page_swap_info(page);
if (sis->flags & SWP_FILE) {
struct kiocb kiocb;
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 0cb36fb..7eded9c 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -67,7 +67,7 @@ void show_swap_cache_info(void)
* __add_to_swap_cache resembles add_to_page_cache_locked on swapper_space,
* but sets SwapCache flag and private instead of mapping and index.
*/
-static int __add_to_swap_cache(struct page *page, swp_entry_t entry)
+int __add_to_swap_cache(struct page *page, swp_entry_t entry)
{
int error;
--
1.8.1.1
next prev parent reply other threads:[~2013-01-29 21:40 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-29 21:40 [PATCHv4 0/7] zswap: compressed swap caching Seth Jennings
2013-01-29 21:40 ` [PATCHv4 1/7] debugfs: add get/set for atomic types Seth Jennings
2013-01-29 21:40 ` [PATCHv4 2/7] zsmalloc: promote to lib/ Seth Jennings
2013-01-29 22:51 ` Andrew Morton
2013-01-30 16:28 ` Seth Jennings
2013-01-30 23:34 ` Andrew Morton
2013-01-31 5:35 ` Minchan Kim
2013-02-13 16:00 ` Seth Jennings
2013-01-29 21:40 ` [PATCHv4 3/7] zswap: add to mm/ Seth Jennings
2013-01-31 7:07 ` Minchan Kim
2013-01-31 19:06 ` Seth Jennings
2013-01-31 20:07 ` Robert Jennings
2013-02-01 2:38 ` Minchan Kim
2013-02-01 15:31 ` Seth Jennings
2013-02-01 17:46 ` Seth Jennings
2013-01-29 21:40 ` Seth Jennings [this message]
2013-01-29 21:40 ` [PATCHv4 5/7] mm: allow for outstanding swap writeback accounting Seth Jennings
2013-01-29 21:40 ` [PATCHv4 6/7] zswap: add flushing support Seth Jennings
2013-01-29 23:03 ` Andrew Morton
2013-02-01 7:27 ` Minchan Kim
2013-02-13 6:24 ` Seth Jennings
2013-01-29 21:40 ` [PATCHv4 7/7] zswap: add documentation Seth Jennings
2013-01-29 23:07 ` Andrew Morton
2013-01-29 22:14 ` [PATCHv4 0/7] zswap: compressed swap caching Joe Perches
2013-01-29 22:49 ` Seth Jennings
2013-01-30 4:32 ` Minchan Kim
2013-01-30 16:01 ` Seth Jennings
2013-02-01 1:39 ` Simon Jeons
2013-02-01 15:13 ` Seth Jennings
2013-02-03 0:17 ` Simon Jeons
2013-02-04 14:56 ` Seth Jennings
2013-02-04 1:03 ` Simon Jeons
2013-02-04 15:07 ` Seth Jennings
[not found] ` <5110287A.5050200@linux.vnet.ibm.com>
2013-02-04 21:45 ` Seth Jennings
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