From: Andrew Morton <akpm@linux-foundation.org>
To: Wei Yang <richard.weiyang@gmail.com>
Cc: ying.huang@intel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 3/3] mm/swapfile.c: count won't be bigger than SWAP_MAP_MAX
Date: Fri, 1 May 2020 15:48:53 -0700 [thread overview]
Message-ID: <20200501154853.bca4cfb7b2558bd43a4942f3@linux-foundation.org> (raw)
In-Reply-To: <20200501015259.32237-3-richard.weiyang@gmail.com>
On Fri, 1 May 2020 01:52:59 +0000 Wei Yang <richard.weiyang@gmail.com> wrote:
> When the condition is true, there are two possibilities:
I'm struggling with this one.
> 1. count == SWAP_MAP_BAD
> 2. count == (SWAP_MAP_MAX & COUNT_CONTINUED) == SWAP_MAP_SHMEM
I'm not sure what 2. is trying to say. For a start, (SWAP_MAP_MAX &
COUNT_CONTINUED) is zero. I guess it meant "|"?
Also, the return value documentation says we return EINVAL for migration
entries. Where's that happening, or is the comment out of date?
> The first case would be filtered by the first if in __swap_duplicate().
>
> And the second case means this swap entry is for shmem. Since we never
> do another duplication for shmem swap entry. This won't happen neither.
next prev parent reply other threads:[~2020-05-01 22:48 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-01 1:52 [PATCH 1/3] mm/swapfile.c: classify SWAP_MAP_XXX to make it more readable Wei Yang
2020-05-01 1:52 ` [PATCH 2/3] mm/swapfile.c: __swap_entry_free() always free 1 entry Wei Yang
2020-05-01 1:52 ` [PATCH 3/3] mm/swapfile.c: count won't be bigger than SWAP_MAP_MAX Wei Yang
2020-05-01 22:48 ` Andrew Morton [this message]
2020-05-02 13:29 ` Wei Yang
2020-05-02 13:41 ` Wei Yang
2020-05-06 8:22 ` Huang, Ying
2020-05-07 22:20 ` Wei Yang
2020-05-07 23:48 ` Huang, Ying
2020-05-08 21:19 ` Wei Yang
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