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From: Andrew Morton <akpm@linux-foundation.org>
To: Miaohe Lin <linmiaohe@huawei.com>
Cc: NeilBrown <neilb@suse.de>, <willy@infradead.org>,
	<vbabka@suse.cz>, <dhowells@redhat.com>, <apopple@nvidia.com>,
	<david@redhat.com>, <surenb@google.com>, <peterx@redhat.com>,
	<naoya.horiguchi@nec.com>, <linux-mm@kvack.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 11/15] mm/swap: add helper swap_offset_available()
Date: Tue, 17 May 2022 16:39:16 -0700	[thread overview]
Message-ID: <20220517163916.71ab9aa1ec095bbc57b82f98@linux-foundation.org> (raw)
In-Reply-To: <9319a62b-f43d-8ee9-77b9-a1afee7dbc10@huawei.com>

On Tue, 10 May 2022 10:03:19 +0800 Miaohe Lin <linmiaohe@huawei.com> wrote:

> On 2022/5/10 8:45, NeilBrown wrote:
> > On Mon, 09 May 2022, Miaohe Lin wrote:
> >> Add helper swap_offset_available() to remove some duplicated codes.
> >> Minor readability improvement.
> > 
> > I don't think that putting the spin_lock() inside the inline helper is
> > good for readability.
> > If the function was called
> >    swap_offset_available_and_locked()
> 
> Yes, swap_offset_available_and_locked should be more suitable as we do the spin_lock
> inside it. Will do this in next version.
> 

--- a/mm/swapfile.c~mm-swap-add-helper-swap_offset_available-fix
+++ a/mm/swapfile.c
@@ -775,7 +775,8 @@ static void set_cluster_next(struct swap
 	this_cpu_write(*si->cluster_next_cpu, next);
 }
 
-static inline bool swap_offset_available(struct swap_info_struct *si, unsigned long offset)
+static bool swap_offset_available_and_locked(struct swap_info_struct *si,
+					     unsigned long offset)
 {
 	if (data_race(!si->swap_map[offset])) {
 		spin_lock(&si->lock);
@@ -967,7 +968,7 @@ done:
 scan:
 	spin_unlock(&si->lock);
 	while (++offset <= READ_ONCE(si->highest_bit)) {
-		if (swap_offset_available(si, offset))
+		if (swap_offset_available_and_locked(si, offset))
 			goto checks;
 		if (unlikely(--latency_ration < 0)) {
 			cond_resched();
@@ -977,7 +978,7 @@ scan:
 	}
 	offset = si->lowest_bit;
 	while (offset < scan_base) {
-		if (swap_offset_available(si, offset))
+		if (swap_offset_available_and_locked(si, offset))
 			goto checks;
 		if (unlikely(--latency_ration < 0)) {
 			cond_resched();
_



  reply	other threads:[~2022-05-17 23:39 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-09 13:14 [PATCH 00/15] A few cleanup patches for swap Miaohe Lin
2022-05-09 13:14 ` [PATCH 01/15] mm/swap: use helper is_swap_pte() in swap_vma_readahead Miaohe Lin
2022-05-12 13:26   ` David Hildenbrand
2022-05-18  8:31   ` Oscar Salvador
2022-05-09 13:14 ` [PATCH 02/15] mm/swap: use helper macro __ATTR_RW Miaohe Lin
2022-05-12 13:28   ` David Hildenbrand
2022-05-18  8:46   ` Oscar Salvador
2022-05-09 13:14 ` [PATCH 03/15] mm/swap: fold __swap_info_get() into its sole caller Miaohe Lin
2022-05-12 13:29   ` David Hildenbrand
2022-05-18  8:56   ` Oscar Salvador
2022-05-09 13:14 ` [PATCH 04/15] mm/swap: remove unneeded return value of free_swap_slot Miaohe Lin
2022-05-12 13:30   ` David Hildenbrand
2022-05-18  9:00   ` Oscar Salvador
2022-05-09 13:14 ` [PATCH 05/15] mm/swap: print bad swap offset entry in get_swap_device Miaohe Lin
2022-05-12 13:32   ` David Hildenbrand
2022-05-18  9:36   ` Oscar Salvador
2022-05-09 13:14 ` [PATCH 06/15] mm/swap: remove buggy cache->nr check in refill_swap_slots_cache Miaohe Lin
2022-05-12 13:37   ` David Hildenbrand
2022-05-16  2:00     ` Miaohe Lin
2022-05-17 23:39       ` Andrew Morton
2022-05-18  9:37   ` Oscar Salvador
2022-05-09 13:14 ` [PATCH 07/15] mm/swap: remove unneeded p != NULL check in __swap_duplicate Miaohe Lin
2022-05-12 13:37   ` David Hildenbrand
2022-05-18  9:40   ` Oscar Salvador
2022-05-09 13:14 ` [PATCH 08/15] mm/swap: make page_swapcount and __lru_add_drain_all Miaohe Lin
2022-05-12 13:39   ` David Hildenbrand
2022-05-18  9:46   ` Oscar Salvador
2022-05-19  1:54     ` Miaohe Lin
2022-05-09 13:14 ` [PATCH 09/15] mm/swap: avoid calling swp_swap_info when try to check SWP_STABLE_WRITES Miaohe Lin
2022-05-10  0:28   ` NeilBrown
2022-05-10  2:21     ` Miaohe Lin
2022-05-17 23:39       ` Andrew Morton
2022-05-09 13:14 ` [PATCH 10/15] mm/swap: break the loop if matching device is found Miaohe Lin
2022-05-09 21:16   ` Andrew Morton
2022-05-10  2:10     ` Miaohe Lin
2022-05-09 13:14 ` [PATCH 11/15] mm/swap: add helper swap_offset_available() Miaohe Lin
2022-05-10  0:45   ` NeilBrown
2022-05-10  2:03     ` Miaohe Lin
2022-05-17 23:39       ` Andrew Morton [this message]
2022-05-09 13:14 ` [PATCH 12/15] mm/swap: fix the obsolete comment for SWP_TYPE_SHIFT Miaohe Lin
2022-05-12 13:41   ` David Hildenbrand
2022-05-09 13:14 ` [PATCH 13/15] mm/swap: clean up the comment of find_next_to_unuse Miaohe Lin
2022-05-12 13:42   ` David Hildenbrand
2022-05-09 13:14 ` [PATCH 14/15] mm/swap: fix the comment of get_kernel_pages Miaohe Lin
2022-05-12 13:45   ` David Hildenbrand
2022-05-13  6:15     ` Miaohe Lin
2022-05-17 23:39       ` Andrew Morton
2022-05-09 13:14 ` [PATCH 15/15] mm/swap: fix comment about swap extent Miaohe Lin
2022-05-17 23:42 ` [PATCH 00/15] A few cleanup patches for swap Andrew Morton
2022-05-18  1:52   ` Miaohe Lin

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