From: Matthew Wilcox <willy@infradead.org>
To: Mike Marshall <hubcap@omnibond.com>
Cc: David Howells <dhowells@redhat.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [RFC PATCH v2] implement orangefs_readahead
Date: Sat, 27 Mar 2021 15:56:30 +0000 [thread overview]
Message-ID: <20210327155630.GJ1719932@casper.infradead.org> (raw)
In-Reply-To: <CAOg9mSRCdaBfLABFYvikHPe1YH6TkTx2tGU186RDso0S=z-S4A@mail.gmail.com>
On Sat, Mar 27, 2021 at 11:40:08AM -0400, Mike Marshall wrote:
> int ret;
>
> loff_t new_start = readahead_index(rac) * PAGE_SIZE;
That looks like readahead_pos() to me.
> size_t new_len = 524288;
> readahead_expand(rac, new_start, new_len);
>
> npages = readahead_count(rac);
> offset = readahead_pos(rac);
> i_pages = &file->f_mapping->i_pages;
>
> iov_iter_xarray(&iter, READ, i_pages, offset, npages * PAGE_SIZE);
readahead_length()?
> /* read in the pages. */
> ret = wait_for_direct_io(ORANGEFS_IO_READ, inode, &offset, &iter,
> npages * PAGE_SIZE, inode->i_size, NULL, NULL, file);
>
> /* clean up. */
> while ((page = readahead_page(rac))) {
> page_endio(page, false, 0);
> put_page(page);
> }
> }
What if wait_for_direct_io() returns an error? Shouldn't you be calling
page_endio(page, false, ret)
?
> On Sat, Mar 27, 2021 at 9:57 AM Matthew Wilcox <willy@infradead.org> wrote:
> >
> > On Sat, Mar 27, 2021 at 08:31:38AM +0000, David Howells wrote:
> > > However, in Mike's orangefs_readahead_cleanup(), he could replace:
> > >
> > > rcu_read_lock();
> > > xas_for_each(&xas, page, last) {
> > > page_endio(page, false, 0);
> > > put_page(page);
> > > }
> > > rcu_read_unlock();
> > >
> > > with:
> > >
> > > while ((page = readahead_page(ractl))) {
> > > page_endio(page, false, 0);
> > > put_page(page);
> > > }
> > >
> > > maybe?
> >
> > I'd rather see that than open-coded use of the XArray. It's mildly
> > slower, but given that we're talking about doing I/O, probably not enough
> > to care about.
next prev parent reply other threads:[~2021-03-27 15:57 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-31 22:25 [RFC PATCH] implement orangefs_readahead Mike Marshall
2021-02-01 13:08 ` Matthew Wilcox
2021-02-02 3:32 ` Mike Marshall
2021-03-13 15:31 ` [RFC PATCH v2] " Mike Marshall
2021-03-17 3:04 ` Mike Marshall
2021-03-24 11:10 ` David Howells
2021-03-27 2:55 ` Mike Marshall
2021-03-27 3:50 ` Matthew Wilcox
2021-03-27 8:31 ` David Howells
2021-03-27 13:56 ` Matthew Wilcox
2021-03-27 15:40 ` Mike Marshall
2021-03-27 15:56 ` Matthew Wilcox [this message]
2021-03-28 3:04 ` Mike Marshall
2021-03-29 1:51 ` Mike Marshall
2021-03-29 9:37 ` David Howells
2021-03-29 23:25 ` Mike Marshall
[not found] ` <3726695.1617284551@warthog.procyon.org.uk >
2021-04-13 15:08 ` David Howells
2021-04-16 14:36 ` Mike Marshall
2021-04-16 15:14 ` Matthew Wilcox
2021-04-25 1:51 ` Mike Marshall
2021-04-16 15:41 ` David Howells
2021-04-25 1:43 ` Mike Marshall
2021-04-25 7:49 ` David Howells
2021-04-26 14:53 ` Mike Marshall
2021-04-26 19:01 ` Mike Marshall
2021-04-26 20:01 ` David Howells
2021-04-26 8:37 ` David Howells
2021-04-01 13:42 ` David Howells
2021-04-08 20:39 ` Mike Marshall
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