From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754815Ab3A1Vzu (ORCPT ); Mon, 28 Jan 2013 16:55:50 -0500 Received: from e38.co.us.ibm.com ([32.97.110.159]:36113 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754135Ab3A1Vzp (ORCPT ); Mon, 28 Jan 2013 16:55:45 -0500 From: Seth Jennings To: Andrew Morton Cc: Seth Jennings , Greg Kroah-Hartman , Nitin Gupta , Minchan Kim , Konrad Rzeszutek Wilk , Dan Magenheimer , Robert Jennings , Jenifer Hopper , Mel Gorman , Johannes Weiner , Rik van Riel , Larry Woodman , Benjamin Herrenschmidt , Dave Hansen , linux-mm@kvack.org, linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org Subject: [PATCHv3 4/6] mm: allow for outstanding swap writeback accounting Date: Mon, 28 Jan 2013 15:49:25 -0600 Message-Id: <1359409767-30092-5-git-send-email-sjenning@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1359409767-30092-1-git-send-email-sjenning@linux.vnet.ibm.com> References: <1359409767-30092-1-git-send-email-sjenning@linux.vnet.ibm.com> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13012821-5518-0000-0000-00000B14C3C7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Seth Jennings --- include/linux/swap.h | 4 +++- mm/page_io.c | 12 +++++++----- 2 files changed, 10 insertions(+), 6 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index fc8920d..98981f0 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -321,7 +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 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 1cb382d..56276fe 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; @@ -179,7 +179,8 @@ bad_bmap: goto out; } -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)); /* * We may have stale swap cache pages in memory: notice @@ -199,12 +200,13 @@ 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; @@ -236,7 +238,7 @@ 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); -- 1.7.9.5