From: Fengguang Wu <fengguang.wu@intel.com>
To: Ni zhan Chen <nizhan.chen@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>,
YingHang Zhu <casualfisher@gmail.com>,
akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: readahead: remove redundant ra_pages in file_ra_state
Date: Fri, 26 Oct 2012 14:58:55 +0800 [thread overview]
Message-ID: <20121026065855.GA9179@localhost> (raw)
In-Reply-To: <5089F5AD.5040708@gmail.com>
> static void shrink_readahead_size_eio(struct file *filp,
> struct file_ra_state *ra)
> {
> - ra->ra_pages /= 4;
> + spin_lock(&filp->f_lock);
> + filp->f_mode |= FMODE_RANDOM;
> + spin_unlock(&filp->f_lock);
>
> As the example in comment above this function, the read maybe still
> sequential, and it will waste IO bandwith if modify to FMODE_RANDOM
> directly.
Yes immediately disabling readahead may hurt IO performance, the
original '/ 4' may perform better when there are only 1-3 IO errors
encountered.
Thanks,
Fengguang
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
From: Fengguang Wu <fengguang.wu@intel.com>
To: Ni zhan Chen <nizhan.chen@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>,
YingHang Zhu <casualfisher@gmail.com>,
akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: readahead: remove redundant ra_pages in file_ra_state
Date: Fri, 26 Oct 2012 14:58:55 +0800 [thread overview]
Message-ID: <20121026065855.GA9179@localhost> (raw)
In-Reply-To: <5089F5AD.5040708@gmail.com>
> static void shrink_readahead_size_eio(struct file *filp,
> struct file_ra_state *ra)
> {
> - ra->ra_pages /= 4;
> + spin_lock(&filp->f_lock);
> + filp->f_mode |= FMODE_RANDOM;
> + spin_unlock(&filp->f_lock);
>
> As the example in comment above this function, the read maybe still
> sequential, and it will waste IO bandwith if modify to FMODE_RANDOM
> directly.
Yes immediately disabling readahead may hurt IO performance, the
original '/ 4' may perform better when there are only 1-3 IO errors
encountered.
Thanks,
Fengguang
next prev parent reply other threads:[~2012-10-26 6:58 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-23 12:46 [PATCH] mm: readahead: remove redundant ra_pages in file_ra_state Ying Zhu
2012-10-23 12:46 ` Ying Zhu
2012-10-23 13:21 ` Ni zhan Chen
2012-10-23 13:21 ` Ni zhan Chen
[not found] ` <CAA9v8mGMa3SDD1OLTG_wdhCGx7K-0kvSV1+MRi9uCGTz6zZaLg@mail.gmail.com>
2012-10-23 13:41 ` YingHang Zhu
2012-10-23 13:41 ` YingHang Zhu
2012-10-24 1:02 ` Ni zhan Chen
2012-10-24 1:02 ` Ni zhan Chen
2012-10-24 1:33 ` YingHang Zhu
2012-10-24 1:33 ` YingHang Zhu
2012-10-23 22:47 ` Dave Chinner
2012-10-23 22:47 ` Dave Chinner
2012-10-23 23:53 ` YingHang Zhu
2012-10-23 23:53 ` YingHang Zhu
2012-10-24 20:19 ` Dave Chinner
2012-10-24 20:19 ` Dave Chinner
2012-10-25 0:17 ` YingHang Zhu
2012-10-25 0:17 ` YingHang Zhu
2012-10-25 1:48 ` Ni zhan Chen
2012-10-25 1:48 ` Ni zhan Chen
2012-10-25 1:50 ` Dave Chinner
2012-10-25 1:50 ` Dave Chinner
2012-10-25 2:04 ` YingHang Zhu
2012-10-25 2:04 ` YingHang Zhu
2012-10-25 2:12 ` Ni zhan Chen
2012-10-25 2:12 ` Ni zhan Chen
2012-10-25 2:31 ` YingHang Zhu
2012-10-25 2:31 ` YingHang Zhu
2012-10-25 2:58 ` Fengguang Wu
2012-10-25 2:58 ` Fengguang Wu
2012-10-25 3:12 ` YingHang Zhu
2012-10-25 3:12 ` YingHang Zhu
2012-10-26 0:25 ` Dave Chinner
2012-10-26 0:25 ` Dave Chinner
2012-10-26 1:27 ` Fengguang Wu
2012-10-26 1:27 ` Fengguang Wu
2012-10-26 2:30 ` Ni zhan Chen
2012-10-26 2:30 ` Ni zhan Chen
2012-10-26 3:28 ` YingHang Zhu
2012-10-26 3:28 ` YingHang Zhu
2012-10-26 3:51 ` Ni zhan Chen
2012-10-26 3:51 ` Ni zhan Chen
2012-10-26 4:35 ` YingHang Zhu
2012-10-26 4:35 ` YingHang Zhu
2012-10-26 6:58 ` Fengguang Wu [this message]
2012-10-26 6:58 ` Fengguang Wu
2012-10-26 7:03 ` Ni zhan Chen
2012-10-26 7:03 ` Ni zhan Chen
2012-10-26 7:09 ` Fengguang Wu
2012-10-26 7:09 ` Fengguang Wu
2012-10-26 7:19 ` Ni zhan Chen
2012-10-26 7:19 ` Ni zhan Chen
2012-10-26 7:36 ` Fengguang Wu
2012-10-26 7:36 ` Fengguang Wu
2012-10-26 7:47 ` Ni zhan Chen
2012-10-26 7:47 ` Ni zhan Chen
2012-10-26 8:02 ` Fengguang Wu
2012-10-26 8:02 ` Fengguang Wu
2012-10-26 8:08 ` Ni zhan Chen
2012-10-26 8:08 ` Ni zhan Chen
2012-10-26 8:13 ` YingHang Zhu
2012-10-26 8:13 ` YingHang Zhu
2012-10-26 2:25 ` Ni zhan Chen
2012-10-26 2:25 ` Ni zhan Chen
2012-10-26 3:38 ` YingHang Zhu
2012-10-26 3:38 ` YingHang Zhu
2012-10-26 3:55 ` Fengguang Wu
2012-10-26 3:55 ` Fengguang Wu
2012-10-26 5:00 ` YingHang Zhu
2012-10-26 5:00 ` YingHang Zhu
2012-10-25 2:38 ` Fengguang Wu
2012-10-25 2:38 ` Fengguang Wu
2012-10-25 3:08 ` YingHang Zhu
2012-10-25 3:08 ` YingHang Zhu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20121026065855.GA9179@localhost \
--to=fengguang.wu@intel.com \
--cc=akpm@linux-foundation.org \
--cc=casualfisher@gmail.com \
--cc=david@fromorbit.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=nizhan.chen@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.