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From: Hao_Xu <[email protected]>
To: Matthew Wilcox <[email protected]>
Cc: Jens Axboe <[email protected]>,
	[email protected], [email protected],
	Johannes Weiner <[email protected]>,
	Andrew Morton <[email protected]>
Subject: Re: [PATCH RFC] mm: fix the sync buffered read to the old way
Date: Thu, 22 Oct 2020 22:55:36 +0800	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

在 2020/10/22 下午10:10, Matthew Wilcox 写道:
> On Thu, Oct 22, 2020 at 09:58:34PM +0800, Hao Xu wrote:
>> The commit 324bcf54c449 changed the code path of async buffered reads
>> to go with the page_cache_sync_readahead() way when readahead is
>> disabled, meanwhile the sync buffered reads are forced to do IO in the
>> above way as well, which makes it go to a more complex code path.
> 
> But ->readpage is (increasingly) synchronous while readahead should be
> used to start async I/Os.  I'm pretty sure Jens meant to do exactly what
> he did.
Yes, we should start async I/Os with readahead, but why should we do the 
sync I/O like syscall read() in this way too when ra->ra_pages is 0?
> 

      reply	other threads:[~2020-10-22 14:55 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-22 13:58 [PATCH RFC] mm: fix the sync buffered read to the old way Hao Xu
2020-10-22 14:10 ` Matthew Wilcox
2020-10-22 14:55   ` Hao_Xu [this message]

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