From: Seth Jennings <sjenning@linux.vnet.ibm.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>,
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>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
devel@driverdev.osuosl.org
Subject: [PATCHv2 7/9] mm: break up swap_writepage() for frontswap backends
Date: Mon, 7 Jan 2013 14:24:38 -0600 [thread overview]
Message-ID: <1357590280-31535-8-git-send-email-sjenning@linux.vnet.ibm.com> (raw)
In-Reply-To: <1357590280-31535-1-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 and
by notified when the writeback completes.
Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
---
include/linux/swap.h | 4 ++++
mm/page_io.c | 22 +++++++++++++++++-----
mm/swap_state.c | 2 +-
3 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 8c66486..a3da829 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -321,6 +321,9 @@ 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 void end_swap_bio_write(struct bio *bio, int err);
+extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
+ void (*end_write_func)(struct bio *, int));
extern int swap_set_page_dirty(struct page *page);
extern void end_swap_bio_read(struct bio *bio, int err);
@@ -335,6 +338,7 @@ 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 c535d39..806085e 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -43,7 +43,7 @@ static struct bio *get_swap_bio(gfp_t gfp_flags,
return bio;
}
-static void end_swap_bio_write(struct bio *bio, int err)
+void end_swap_bio_write(struct bio *bio, int err)
{
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct page *page = bio->bi_io_vec[0].bv_page;
@@ -180,15 +180,16 @@ bad_bmap:
goto out;
}
+int __swap_writepage(struct page *page, struct writeback_control *wbc,
+ void (*end_write_func)(struct bio *, int));
+
/*
* 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);
@@ -200,6 +201,17 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
end_page_writeback(page);
goto out;
}
+ ret = __swap_writepage(page, wbc, end_swap_bio_write);
+out:
+ return ret;
+}
+
+int __swap_writepage(struct page *page, struct writeback_control *wbc,
+ void (*end_write_func)(struct bio *, int))
+{
+ 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;
@@ -227,7 +239,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
return ret;
}
- bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write);
+ bio = get_swap_bio(GFP_NOIO, page, end_write_func);
if (bio == NULL) {
set_page_dirty(page);
unlock_page(page);
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;
--
1.7.9.5
next prev parent reply other threads:[~2013-01-07 20:25 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-07 20:24 [PATCHv2 0/9] zswap: compressed swap caching Seth Jennings
2013-01-07 20:24 ` [PATCHv2 1/9] staging: zsmalloc: add gfp flags to zs_create_pool Seth Jennings
2013-01-25 0:08 ` Nitin Gupta
2013-01-25 1:33 ` Minchan Kim
2013-01-25 15:07 ` Seth Jennings
2013-01-25 15:56 ` Dan Magenheimer
2013-01-28 2:59 ` Minchan Kim
2013-01-30 16:11 ` Konrad Rzeszutek Wilk
2013-01-31 5:21 ` Minchan Kim
2013-01-25 21:26 ` Rik van Riel
2013-01-07 20:24 ` [PATCHv2 2/9] staging: zsmalloc: remove unsed pool name Seth Jennings
2013-01-25 0:09 ` Nitin Gupta
2013-01-25 21:50 ` Rik van Riel
2013-01-07 20:24 ` [PATCHv2 3/9] staging: zsmalloc: add page alloc/free callbacks Seth Jennings
2013-01-25 0:11 ` Nitin Gupta
2013-01-25 21:55 ` Rik van Riel
2013-01-07 20:24 ` [PATCHv2 4/9] staging: zsmalloc: make CLASS_DELTA relative to PAGE_SIZE Seth Jennings
2013-01-25 0:17 ` Nitin Gupta
2013-01-25 16:38 ` Seth Jennings
2013-01-07 20:24 ` [PATCHv2 5/9] debugfs: add get/set for atomic types Seth Jennings
2013-01-07 20:32 ` Greg Kroah-Hartman
2013-01-07 20:41 ` Seth Jennings
2013-01-25 16:45 ` Seth Jennings
2013-01-25 21:35 ` Greg Kroah-Hartman
2013-01-07 20:24 ` [PATCHv2 6/9] zsmalloc: promote to lib/ Seth Jennings
2013-01-28 4:01 ` Minchan Kim
2013-01-28 4:32 ` Minchan Kim
2013-01-28 17:41 ` Seth Jennings
2013-01-07 20:24 ` Seth Jennings [this message]
2013-01-28 4:22 ` [PATCHv2 7/9] mm: break up swap_writepage() for frontswap backends Minchan Kim
2013-01-28 17:26 ` Seth Jennings
2013-01-28 23:46 ` Minchan Kim
2013-01-07 20:24 ` [PATCHv2 8/9] zswap: add to mm/ Seth Jennings
2013-01-08 17:15 ` Dave Hansen
2013-01-08 17:54 ` Dan Magenheimer
2013-01-25 22:44 ` Rik van Riel
2013-01-25 23:15 ` Dan Magenheimer
2013-01-28 15:27 ` Seth Jennings
2013-01-29 10:21 ` Lord Glauber Costa of Sealand
2013-02-07 16:13 ` Seth Jennings
2013-02-11 19:13 ` Dan Magenheimer
2013-01-07 20:24 ` [PATCHv2 9/9] zswap: add documentation Seth Jennings
2013-01-22 18:10 ` [PATCHv2 0/9] zswap: compressed swap caching Seth Jennings
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