From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
To: Minchan Kim <minchan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Cc: kernel-team@lge.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.com>
Subject: Re: [RFC 07/11] mm: remove SWAP_AGAIN in ttu
Date: Fri, 3 Mar 2017 18:24:06 +0530 [thread overview]
Message-ID: <fce4a36a-8b4b-333d-d846-9f6edd86c2e1@linux.vnet.ibm.com> (raw)
In-Reply-To: <1488436765-32350-8-git-send-email-minchan@kernel.org>
On 03/02/2017 12:09 PM, Minchan Kim wrote:
> In 2002, [1] introduced SWAP_AGAIN.
> At that time, ttuo used spin_trylock(&mm->page_table_lock) so it's
Small nit: Please expand "ttuo" here. TTU in the first place is also
not very clear but we have that in many places.
> really easy to contend and fail to hold a lock so SWAP_AGAIN to keep
> LRU status makes sense.
Okay.
>
> However, now we changed it to mutex-based lock and be able to block
> without skip pte so there is a few of small window to return
> SWAP_AGAIN so remove SWAP_AGAIN and just return SWAP_FAIL.
Makes sense.
>
> [1] c48c43e, minimal rmap
> Signed-off-by: Minchan Kim <minchan@kernel.org>
> ---
> mm/rmap.c | 11 +++--------
> mm/vmscan.c | 2 --
> 2 files changed, 3 insertions(+), 10 deletions(-)
>
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 47898a1..da18f21 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1492,13 +1492,10 @@ static int page_mapcount_is_zero(struct page *page)
> * Return values are:
> *
> * SWAP_SUCCESS - we succeeded in removing all mappings
> - * SWAP_AGAIN - we missed a mapping, try again later
> * SWAP_FAIL - the page is unswappable
> */
> int try_to_unmap(struct page *page, enum ttu_flags flags)
> {
> - int ret;
> -
> struct rmap_walk_control rwc = {
> .rmap_one = try_to_unmap_one,
> .arg = (void *)flags,
> @@ -1518,13 +1515,11 @@ int try_to_unmap(struct page *page, enum ttu_flags flags)
> rwc.invalid_vma = invalid_migration_vma;
>
> if (flags & TTU_RMAP_LOCKED)
> - ret = rmap_walk_locked(page, &rwc);
> + rmap_walk_locked(page, &rwc);
> else
> - ret = rmap_walk(page, &rwc);
> + rmap_walk(page, &rwc);
>
> - if (!page_mapcount(page))
> - ret = SWAP_SUCCESS;
> - return ret;
> + return !page_mapcount(page) ? SWAP_SUCCESS: SWAP_FAIL;
Its very simple now. So after the rmap_walk() if page is not mapped any
more return SWAP_SUCCESS otherwise SWAP_FAIL.
--
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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-03-03 12:54 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-02 6:39 [RFC 00/11] make try_to_unmap simple Minchan Kim
2017-03-02 6:39 ` [RFC 01/11] mm: use SWAP_SUCCESS instead of 0 Minchan Kim
2017-03-02 14:27 ` Anshuman Khandual
2017-03-03 3:01 ` Minchan Kim
2017-03-06 9:07 ` Anshuman Khandual
2017-03-07 14:19 ` Kirill A. Shutemov
2017-03-08 6:25 ` Minchan Kim
2017-03-02 6:39 ` [RFC 02/11] mm: remove unncessary ret in page_referenced Minchan Kim
2017-03-02 14:33 ` Anshuman Khandual
2017-03-03 3:03 ` Minchan Kim
2017-03-07 14:20 ` Kirill A. Shutemov
2017-03-02 6:39 ` [RFC 03/11] mm: remove SWAP_DIRTY in ttu Minchan Kim
2017-03-02 7:34 ` Hillf Danton
2017-03-03 2:57 ` Minchan Kim
2017-03-02 14:42 ` Anshuman Khandual
2017-03-07 14:20 ` Kirill A. Shutemov
2017-03-02 6:39 ` [RFC 04/11] mm: remove SWAP_MLOCK check for SWAP_SUCCESS " Minchan Kim
2017-03-02 14:51 ` Anshuman Khandual
2017-03-03 3:04 ` Minchan Kim
2017-03-07 14:26 ` Kirill A. Shutemov
2017-03-08 6:40 ` Minchan Kim
2017-03-02 6:39 ` [RFC 05/11] mm: make the try_to_munlock void function Minchan Kim
2017-03-03 11:43 ` Anshuman Khandual
2017-03-06 2:09 ` Minchan Kim
2017-03-06 9:40 ` Anshuman Khandual
2017-03-07 6:50 ` Minchan Kim
2017-03-07 8:55 ` Anshuman Khandual
2017-03-07 15:17 ` Kirill A. Shutemov
2017-03-08 6:41 ` Minchan Kim
2017-03-02 6:39 ` [RFC 06/11] mm: remove SWAP_MLOCK in ttu Minchan Kim
2017-03-03 12:36 ` Anshuman Khandual
2017-03-06 2:15 ` Minchan Kim
2017-03-07 15:24 ` Kirill A. Shutemov
2017-03-08 6:42 ` Minchan Kim
2017-03-02 6:39 ` [RFC 07/11] mm: remove SWAP_AGAIN " Minchan Kim
2017-03-03 12:54 ` Anshuman Khandual [this message]
2017-03-06 2:16 ` Minchan Kim
2017-03-02 6:39 ` [RFC 08/11] mm: make ttu's return boolean Minchan Kim
2017-03-08 7:13 ` John Hubbard
2017-03-09 6:37 ` Minchan Kim
2017-03-09 6:46 ` John Hubbard
2017-03-02 6:39 ` [RFC 09/11] mm: make rmap_walk void function Minchan Kim
2017-03-02 6:39 ` [RFC 10/11] mm: make rmap_one boolean function Minchan Kim
2017-03-02 6:39 ` [RFC 11/11] mm: remove SWAP_[SUCCESS|AGAIN|FAIL] Minchan Kim
2017-03-03 13:04 ` Anshuman Khandual
2017-03-06 2:18 ` Minchan Kim
2017-03-02 14:22 ` [RFC 00/11] make try_to_unmap simple Anshuman Khandual
2017-03-03 2:11 ` Minchan Kim
2017-03-03 5:39 ` Anshuman Khandual
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=fce4a36a-8b4b-333d-d846-9f6edd86c2e1@linux.vnet.ibm.com \
--to=khandual@linux.vnet.ibm.com \
--cc=akpm@linux-foundation.org \
--cc=hannes@cmpxchg.org \
--cc=kernel-team@lge.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=minchan@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).