linux-kernel - Re: [RFC PATCH 0/1] Large folios in block buffered IO path

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Message-ID: <CAGudoHEN-tOhBbdr5hymbLw3YK6OdaCSfsbOL6LjcQkNhR6_6A@mail.gmail.com>
Date: Wed, 27 Nov 2024 13:28:09 +0100
From: Mateusz Guzik <mjguzik@...il.com>
To: Bharata B Rao <bharata@....com>
Cc: linux-block@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-fsdevel@...r.kernel.org, linux-mm@...ck.org, nikunj@....com, 
	willy@...radead.org, vbabka@...e.cz, david@...hat.com, 
	akpm@...ux-foundation.org, yuzhao@...gle.com, axboe@...nel.dk, 
	viro@...iv.linux.org.uk, brauner@...nel.org, jack@...e.cz, joshdon@...gle.com, 
	clm@...a.com
Subject: Re: [RFC PATCH 0/1] Large folios in block buffered IO path

On Wed, Nov 27, 2024 at 1:18 PM Bharata B Rao <bharata@....com> wrote:
>
> On 27-Nov-24 11:49 AM, Mateusz Guzik wrote:
> > That is to say bare minimum this needs to be benchmarked before/after
> > with the lock removed from the picture, like so:
> >
> > diff --git a/block/fops.c b/block/fops.c
> > index 2d01c9007681..7f9e9e2f9081 100644
> > --- a/block/fops.c
> > +++ b/block/fops.c
> > @@ -534,12 +534,8 @@ const struct address_space_operations def_blk_aops = {
> >   static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence)
> >   {
> >          struct inode *bd_inode = bdev_file_inode(file);
> > -       loff_t retval;
> >
> > -       inode_lock(bd_inode);
> > -       retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
> > -       inode_unlock(bd_inode);
> > -       return retval;
> > +       return fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
> >   }
> >
> >   static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
> >
> > To be aborted if it blows up (but I don't see why it would).
>
> Thanks for this fix, will try and get back with results.
>

Please make sure to have results just with this change, no messing
with folio sizes so that I have something for the patch submission.

-- 
Mateusz Guzik <mjguzik gmail.com>