From: "yukuai (C)" <yukuai3@huawei.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: <hch@infradead.org>, <darrick.wong@oracle.com>,
<linux-xfs@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <houtao1@huawei.com>,
<zhengbin13@huawei.com>, <yi.zhang@huawei.com>
Subject: Re: [RFC] iomap: fix race between readahead and direct write
Date: Sun, 19 Jan 2020 09:57:03 +0800 [thread overview]
Message-ID: <857fa4e7-c529-40cf-9916-151d91e815c4@huawei.com> (raw)
In-Reply-To: <20200119014213.GA16943@bombadil.infradead.org>
On 2020/1/19 9:42, Matthew Wilcox wrote:
> Did you read my patch series? The current code allocates pages,
> but does not put them in the page cache until after iomap is called.
> My patch series changes that to put the pages in the page cache as soon
> as they're allocated, and before iomap is called.
The current code to determin if page need to be allocated:
page = xa_load(&mapping->i_pages, page_offset);
if (page && !xa_is_value(page)) {
/*
┊* Page already present? Kick off the current batch of
┊* contiguous pages before continuing with the next
┊* batch.
┊*/
if (nr_pages)
read_pages(mapping, filp, &page_pool, nr_pages,
gfp_mask);
nr_pages = 0;
continue;
}
page = __page_cache_alloc(gfp_mask);
if (!page)
break;
Page will be allocated if the page do not exist in page cache. And I
don't see your patch series change that. Or am I missing something?
Thanks!
Yu Kuai
next prev parent reply other threads:[~2020-01-19 1:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-16 6:36 [RFC] iomap: fix race between readahead and direct write yu kuai
2020-01-16 15:32 ` Jan Kara
2020-01-17 9:39 ` yukuai (C)
2020-01-17 11:05 ` Jan Kara
2020-01-17 16:24 ` Darrick J. Wong
2020-01-19 1:25 ` yukuai (C)
2020-01-19 1:17 ` yukuai (C)
2020-01-20 11:42 ` Jan Kara
2020-01-18 23:08 ` Matthew Wilcox
2020-01-19 1:34 ` yukuai (C)
2020-01-19 1:42 ` Matthew Wilcox
2020-01-19 1:57 ` yukuai (C) [this message]
2020-01-19 2:51 ` yukuai (C)
2020-01-19 3:01 ` Gao Xiang
2020-01-19 3:15 ` yukuai (C)
2020-01-19 6:14 ` Matthew Wilcox
2020-01-19 6:55 ` yukuai (C)
2020-01-19 7:58 ` Matthew Wilcox
2020-01-19 11:21 ` yukuai (C)
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