From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx141.postini.com [74.125.245.141]) by kanga.kvack.org (Postfix) with SMTP id 998246B0071 for ; Sun, 10 Jun 2012 06:50:10 -0400 (EDT) Received: by mail-bk0-f41.google.com with SMTP id jm19so3841575bkc.14 for ; Sun, 10 Jun 2012 03:50:10 -0700 (PDT) From: Sasha Levin Subject: [PATCH v3 05/10] mm: frontswap: split frontswap_shrink further to simplify locking Date: Sun, 10 Jun 2012 12:51:03 +0200 Message-Id: <1339325468-30614-6-git-send-email-levinsasha928@gmail.com> In-Reply-To: <1339325468-30614-1-git-send-email-levinsasha928@gmail.com> References: <1339325468-30614-1-git-send-email-levinsasha928@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: dan.magenheimer@oracle.com, konrad.wilk@oracle.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sasha Levin Split frontswap_shrink to simplify the locking in the original code. Also, assert that the function that was split still runs under the swap spinlock. Signed-off-by: Sasha Levin --- mm/frontswap.c | 36 +++++++++++++++++++++--------------- 1 files changed, 21 insertions(+), 15 deletions(-) diff --git a/mm/frontswap.c b/mm/frontswap.c index faa43b7..e6353d9 100644 --- a/mm/frontswap.c +++ b/mm/frontswap.c @@ -265,6 +265,24 @@ static int __frontswap_unuse_pages(unsigned long total, unsigned long *unused, return ret; } +static int __frontswap_shrink(unsigned long target_pages, + unsigned long *pages_to_unuse, + int *type) +{ + unsigned long total_pages = 0, total_pages_to_unuse; + + assert_spin_locked(&swap_lock); + + total_pages = __frontswap_curr_pages(); + if (total_pages <= target_pages) { + /* Nothing to do */ + *pages_to_unuse = 0; + return 0; + } + total_pages_to_unuse = total_pages - target_pages; + return __frontswap_unuse_pages(total_pages_to_unuse, pages_to_unuse, type); +} + /* * Frontswap, like a true swap device, may unnecessarily retain pages * under certain circumstances; "shrink" frontswap is essentially a @@ -275,10 +293,8 @@ static int __frontswap_unuse_pages(unsigned long total, unsigned long *unused, */ void frontswap_shrink(unsigned long target_pages) { - unsigned long total_pages = 0, total_pages_to_unuse; unsigned long pages_to_unuse = 0; int type, ret; - bool locked = false; /* * we don't want to hold swap_lock while doing a very @@ -286,20 +302,10 @@ void frontswap_shrink(unsigned long target_pages) * so restart scan from swap_list.head each time */ spin_lock(&swap_lock); - locked = true; - total_pages = __frontswap_curr_pages(); - if (total_pages <= target_pages) - goto out; - total_pages_to_unuse = total_pages - target_pages; - ret = __frontswap_unuse_pages(total_pages_to_unuse, &pages_to_unuse, &type); - if (ret < 0) - goto out; - locked = false; + ret = __frontswap_shrink(target_pages, &pages_to_unuse, &type); spin_unlock(&swap_lock); - try_to_unuse(type, true, pages_to_unuse); -out: - if (locked) - spin_unlock(&swap_lock); + if (ret == 0 && pages_to_unuse) + try_to_unuse(type, true, pages_to_unuse); return; } EXPORT_SYMBOL(frontswap_shrink); -- 1.7.8.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org