> From: Bob Liu [mailto:lliubbo@xxxxxxxxx] > Sent: Monday, April 01, 2013 9:50 PM > To: akpm@xxxxxxxxxxxxxxxxxxxx > Cc: linux-mm@xxxxxxxxx; minchan@xxxxxxxxxx; sjenning@xxxxxxxxxxxxxxxxxx; rcj@xxxxxxxxxxxxxxxxxx; > ngupta@xxxxxxxxxx; konrad.wilk@xxxxxxxxxx; dan.magenheimer@xxxxxxxxxx; Bob Liu > Subject: [PATCH 2/2] mm: allow for outstanding swap writeback accounting > > From: Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx> > > To prevent flooding the swap device with writebacks, frontswap > backends need to count and limit the number of outstanding > writebacks. The incrementing of the counter can be done before > the call to __swap_writepage(). However, the caller must receive > a notification when the writeback completes in order to decrement > the counter. > > To achieve this functionality, this patch modifies > __swap_writepage() to take the bio completion callback function > as an argument. > > end_swap_bio_write(), the normal bio completion function, is also > made non-static so that code doing the accounting can call it > after the accounting is done. > > Acked-by: Minchan Kim <minchan@xxxxxxxxxx> > Signed-off-by: Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Bob Liu <bob.liu@xxxxxxxxxx> Reviewed-by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx> > --- > include/linux/swap.h | 4 +++- > mm/page_io.c | 9 +++++---- > 2 files changed, 8 insertions(+), 5 deletions(-) > > diff --git a/include/linux/swap.h b/include/linux/swap.h > index 76f6c3b..b5b12c7 100644 > --- a/include/linux/swap.h > +++ b/include/linux/swap.h > @@ -330,7 +330,9 @@ 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 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); > > diff --git a/mm/page_io.c b/mm/page_io.c > index 8e6bcf1..8e0e5c0 100644 > --- a/mm/page_io.c > +++ b/mm/page_io.c > @@ -42,7 +42,7 @@ 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; > @@ -197,12 +197,13 @@ int swap_writepage(struct page *page, struct writeback_control *wbc) > end_page_writeback(page); > goto out; > } > - ret = __swap_writepage(page, wbc); > + ret = __swap_writepage(page, wbc, end_swap_bio_write); > out: > return ret; > } > > -int __swap_writepage(struct page *page, struct writeback_control *wbc) > +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; > @@ -234,7 +235,7 @@ 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); > -- > 1.7.10.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href