From: Dave Hansen <dave.hansen@linux.intel.com>
To: "Huang, Ying" <ying.huang@intel.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Michal Hocko <mhocko@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Shaohua Li <shli@kernel.org>, Hugh Dickins <hughd@google.com>,
Minchan Kim <minchan@kernel.org>, Rik van Riel <riel@redhat.com>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
Dan Williams <dan.j.williams@intel.com>
Subject: Re: [PATCH 1/6] swap: Add comments to lock_cluster_or_swap_info()
Date: Fri, 13 Jul 2018 03:48:28 -0700 [thread overview]
Message-ID: <3c3a4dce-980d-0405-d269-1da9e62b1344@linux.intel.com> (raw)
In-Reply-To: <20180712233636.20629-2-ying.huang@intel.com>
> +/*
> + * At most times, fine grained cluster lock is sufficient to protect
Can we call out those times, please?
> + * the operations on sis->swap_map.
Please be careful with the naming. You can call it 'si' because that's
what the function argument is named. Or, swap_info_struct because
that's the struct name. Calling it 'sis' is a bit sloppy, no?
> No need to acquire gross grained
"coarse" is a conventional antonym for "fine".
> + * sis->lock. But cluster and cluster lock isn't available for HDD,
> + * so sis->lock will be instead for them.
> + */
> static inline struct swap_cluster_info *lock_cluster_or_swap_info(
> struct swap_info_struct *si,
> unsigned long offset)
What I already knew was: there are two locks. We use one sometimes and
the other at other times.
What I don't know is why there are two locks, and the heuristics why we
choose between them. This comment doesn't help explain the things I
don't know.
next prev parent reply other threads:[~2018-07-13 10:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-12 23:36 [PATCH 0/6] swap: THP optimizing refactoring Huang, Ying
2018-07-12 23:36 ` [PATCH 1/6] swap: Add comments to lock_cluster_or_swap_info() Huang, Ying
2018-07-13 10:48 ` Dave Hansen [this message]
2018-07-14 4:07 ` Huang, Ying
2018-07-12 23:36 ` [PATCH 2/6] mm/swapfile.c: Replace some #ifdef with IS_ENABLED() Huang, Ying
2018-07-13 18:38 ` Daniel Jordan
2018-07-13 18:55 ` Daniel Jordan
2018-07-12 23:36 ` [PATCH 3/6] swap: Unify normal/huge code path in swap_page_trans_huge_swapped() Huang, Ying
2018-07-13 20:15 ` Daniel Jordan
2018-07-14 12:53 ` Huang, Ying
2018-07-12 23:36 ` [PATCH 4/6] swap: Unify normal/huge code path in put_swap_page() Huang, Ying
2018-07-12 23:36 ` [PATCH 5/6] swap: Add __swap_entry_free_locked() Huang, Ying
2018-07-12 23:36 ` [PATCH 6/6] swap, put_swap_page: Share more between huge/normal code path Huang, Ying
2018-07-13 20:18 ` Daniel Jordan
2018-07-14 12:57 ` Huang, Ying
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=3c3a4dce-980d-0405-d269-1da9e62b1344@linux.intel.com \
--to=dave.hansen@linux.intel.com \
--cc=akpm@linux-foundation.org \
--cc=dan.j.williams@intel.com \
--cc=daniel.m.jordan@oracle.com \
--cc=hannes@cmpxchg.org \
--cc=hughd@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=minchan@kernel.org \
--cc=riel@redhat.com \
--cc=shli@kernel.org \
--cc=ying.huang@intel.com \
/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).