public inbox for linux-mtd@lists.infradead.org
 help / color / mirror / Atom feed
From: "Joakim Tjernlund" <Joakim.Tjernlund@lumentis.se>
To: <linux-mtd@lists.infradead.org>
Subject: CLEANMARKER question
Date: Sat, 5 Jan 2002 13:23:37 +0100	[thread overview]
Message-ID: <001001c195e3$cd5fb180$5a9240d5@jocke> (raw)

>joakim.tjernlund@lumentis.se said:
>> OK, I suspected that much. So after a CLEANMARKER there can be a
>> NODETYPE_INODE or a NODETYPE_DIRENT?
>
>Or indeed any other type of node, when new ones get invented - yes.
>
>> Why do you do 2 scan_empty() calls in scan_eraseblock() ?
>
>Consider it loop unrolling.
>
>> Well, sofar I have only identified one improvement. One could add an
>> isempty() function in the mtd layer. That would improve scaning for
>> empy flash so that you dont have to mtd->read() into a buffer and then
>> check the buffer for 0xffffffff. How does that sound?
>
>Sounds ugly, but could be effective. Want to benchmark it to see if it's
>really worth it?

I did a very ugly hack to see if there was a big difference.
on my FS(¨~62 MB flash partition, 31% in use) it took
12.2 sec to mount with my ugly hack and it
tackes 13.3 sec without the ugly hack.

I guess it's not worth it.

>
>
>If there's a way to safely avoid having to check all the node CRCs on
>mount, that would also help.

Yes, I once commented out all crc checking in scan just to see what happened
and there was a difference, but I can not remeber how much.

>
>The most useful thing to do, though, would probably be to implement
>checkpointing.
I have seen alot of posts about it but I have no idea on how to proceed
with this.

Would checkpointing  still speed up mount when power is cut and then
restored?

             reply	other threads:[~2002-01-05 12:10 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-01-05 12:23 Joakim Tjernlund [this message]
2002-01-05 12:59 ` CLEANMARKER question David Woodhouse
  -- strict thread matches above, loose matches on Subject: below --
2001-11-12 12:14 Cache mappings and invalidate Joakim Tjernlund
2002-01-04  8:59 ` CLEANMARKER question Joakim Tjernlund
2002-01-04  9:42   ` David Woodhouse
2002-01-04 10:33     ` Joakim Tjernlund
2002-01-04 10:41       ` David Woodhouse

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='001001c195e3$cd5fb180$5a9240d5@jocke' \
    --to=joakim.tjernlund@lumentis.se \
    --cc=linux-mtd@lists.infradead.org \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox