linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: dcache endless loop in d_invalidate
Date: Thu, 25 Oct 2018 13:43:44 +0200	[thread overview]
Message-ID: <20181025134344.75484f14@mschwideX1> (raw)
In-Reply-To: <20181016131528.6aac4876@mschwideX1>

On Tue, 16 Oct 2018 13:15:28 +0200
Martin Schwidefsky <schwidefsky@de.ibm.com> wrote:

> In short, this if-statement in select_collect:
> 
>         if (dentry->d_flags & DCACHE_SHRINK_LIST) {
>                 data->found++;
>         }
> 
> with assumption that "somebody else" will do the shrinking seems broken.
> 
> Do you agree?

If I am not mistaken this problem should be fixed by upstream commit
4fb4887140 "restore cond_resched() in shrink_dcache_parent()"
which goes on top of
ff17fa561a "d_invalidate(): unhash immediately"

Due to the cond_resched() the task that set DCACHE_SHRINK_LIST for the
remaining two dcache entries will be scheduled eventually. This will
allow the task waiting for the deletion of these dcache entries 
to continue, although some CPU cycles may get wasted.

-- 
blue skies,
   Martin.

"Reality continues to ruin my life." - Calvin.


      reply	other threads:[~2018-10-25 11:43 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-16 11:15 Martin Schwidefsky
2018-10-25 11:43 ` Martin Schwidefsky [this message]

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=20181025134344.75484f14@mschwideX1 \
    --to=schwidefsky@de.ibm.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=viro@zeniv.linux.org.uk \
    --subject='Re: dcache endless loop in d_invalidate' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).