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Message-ID: <7c834335-9872-4de3-9e53-179356826c93@linux.alibaba.com>
Date: Tue, 11 Jun 2024 10:59:27 +0800
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Subject: Re: [PATCH 4/7] mm: shmem: extend shmem_partial_swap_usage() to
 support large folio swap
To: Daniel Gomez <da.gomez@samsung.com>
Cc: "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
 "hughd@google.com" <hughd@google.com>,
 "willy@infradead.org" <willy@infradead.org>,
 "david@redhat.com" <david@redhat.com>,
 "wangkefeng.wang@huawei.com" <wangkefeng.wang@huawei.com>,
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 Pankaj Raghav <p.raghav@samsung.com>, "linux-mm@kvack.org"
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References: <cover.1717673614.git.baolin.wang@linux.alibaba.com>
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 <CGME20240610145327eucas1p1bb32a985f8eaddf8cdda0b5415c1868c@eucas1p1.samsung.com>
 <qlk2dpg2fmro5vzjks45ciwt3qk6nzlurfmlqnjr4ecskgg7ln@w5ba55tgtcsb>
From: Baolin Wang <baolin.wang@linux.alibaba.com>
In-Reply-To: <qlk2dpg2fmro5vzjks45ciwt3qk6nzlurfmlqnjr4ecskgg7ln@w5ba55tgtcsb>
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On 2024/6/10 22:53, Daniel Gomez wrote:
> Hi Baolin,
> On Thu, Jun 06, 2024 at 07:58:54PM +0800, Baolin Wang wrote:
>> To support shmem large folio swapout in the following patches, using
>> xa_get_order() to get the order of the swap entry to calculate the swap
>> usage of shmem.
>>
>> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
>> ---
>>   mm/shmem.c | 7 +++++--
>>   1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/shmem.c b/mm/shmem.c
>> index eefdf5c61c04..0ac71580decb 100644
>> --- a/mm/shmem.c
>> +++ b/mm/shmem.c
>> @@ -865,13 +865,16 @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping,
>>   	struct page *page;
>>   	unsigned long swapped = 0;
>>   	unsigned long max = end - 1;
>> +	int order;
>>   
>>   	rcu_read_lock();
>>   	xas_for_each(&xas, page, max) {
>>   		if (xas_retry(&xas, page))
>>   			continue;
>> -		if (xa_is_value(page))
>> -			swapped++;
>> +		if (xa_is_value(page)) {
>> +			order = xa_get_order(xas.xa, xas.xa_index);
>> +			swapped += 1 << order;
> 
> I'd get rid of order and simply do:
> 
> 	swapped += 1UL << xa_get_order()

OK. Will do.