From: Andrew Morton <akpm@linux-foundation.org>
To: Miaohe Lin <linmiaohe@huawei.com>
Cc: <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH] mm: swap: Use memset to fill the swap_map with SWAP_HAS_CACHE
Date: Sun, 25 Oct 2020 17:14:11 -0700 [thread overview]
Message-ID: <20201025171411.20fce472df99bc43fce7156c@linux-foundation.org> (raw)
In-Reply-To: <20200921122224.7139-1-linmiaohe@huawei.com>
On Mon, 21 Sep 2020 08:22:24 -0400 Miaohe Lin <linmiaohe@huawei.com> wrote:
> We could use helper memset to fill the swap_map with SWAP_HAS_CACHE instead
> of a direct loop here to simplify the code. Also we can remove the local
> variable i and map this way.
>
> ...
>
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -975,8 +975,7 @@ static int swap_alloc_cluster(struct swap_info_struct *si, swp_entry_t *slot)
> {
> unsigned long idx;
> struct swap_cluster_info *ci;
> - unsigned long offset, i;
> - unsigned char *map;
> + unsigned long offset;
>
> /*
> * Should not even be attempting cluster allocations when huge
> @@ -996,9 +995,7 @@ static int swap_alloc_cluster(struct swap_info_struct *si, swp_entry_t *slot)
> alloc_cluster(si, idx);
> cluster_set_count_flag(ci, SWAPFILE_CLUSTER, CLUSTER_FLAG_HUGE);
>
> - map = si->swap_map + offset;
> - for (i = 0; i < SWAPFILE_CLUSTER; i++)
> - map[i] = SWAP_HAS_CACHE;
> + memset(si->swap_map + offset, SWAP_HAS_CACHE, SWAPFILE_CLUSTER);
> unlock_cluster(ci);
> swap_range_alloc(si, offset, SWAPFILE_CLUSTER);
> *slot = swp_entry(si->type, offset);
I suppose so. But it does assume that the ->swapmap array has the type
char. If we ever change that, breakage will ensue.
next prev parent reply other threads:[~2020-10-26 0:14 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-21 12:22 [PATCH] mm: swap: Use memset to fill the swap_map with SWAP_HAS_CACHE Miaohe Lin
2020-10-26 0:14 ` Andrew Morton [this message]
2020-10-07 2:49 linmiaohe
2020-10-26 3:03 linmiaohe
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