Re: [PATCH 0/2] mm/shrinker: make unregister_shrinker() less fragile

All of lore.kernel.org
 help / color / mirror / Atom feed

From: Christoph Hellwig <hch@infradead.org>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] mm/shrinker: make unregister_shrinker() less fragile
Date: Tue, 14 Jul 2015 00:17:59 -0700	[thread overview]
Message-ID: <20150714071759.GD31117@infradead.org> (raw)
In-Reply-To: <20150713092531.GA578@swordfish>

On Mon, Jul 13, 2015 at 06:34:42PM +0900, Sergey Senozhatsky wrote:
> Yes. 'Nice' used in a sense that drivers have logic to release the
> memory anyway; mm asks volunteers (the drivers that have registered
> shrinker callbacks) to release some spare/wasted/etc. when things
> are getting tough (the drivers are not aware of that in general).
> This is surely important to mm, not to the driver though -- it just
> agrees to be 'nice', but even not expected to release any memory at
> all (IOW, this is not a contract).

Not registering the shrinker is a plain and simple memory leak.  Just
like a missing free your driver will appear to work fine for a while,
but eventually the leaks will bring down the whole system including
your driver.

--
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: Christoph Hellwig <hch@infradead.org>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] mm/shrinker: make unregister_shrinker() less fragile
Date: Tue, 14 Jul 2015 00:17:59 -0700	[thread overview]
Message-ID: <20150714071759.GD31117@infradead.org> (raw)
In-Reply-To: <20150713092531.GA578@swordfish>

On Mon, Jul 13, 2015 at 06:34:42PM +0900, Sergey Senozhatsky wrote:
> Yes. 'Nice' used in a sense that drivers have logic to release the
> memory anyway; mm asks volunteers (the drivers that have registered
> shrinker callbacks) to release some spare/wasted/etc. when things
> are getting tough (the drivers are not aware of that in general).
> This is surely important to mm, not to the driver though -- it just
> agrees to be 'nice', but even not expected to release any memory at
> all (IOW, this is not a contract).

Not registering the shrinker is a plain and simple memory leak.  Just
like a missing free your driver will appear to work fine for a while,
but eventually the leaks will bring down the whole system including
your driver.

next prev parent reply	other threads:[~2015-07-14  7:18 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-11  2:51 [PATCH 0/2] mm/shrinker: make unregister_shrinker() less fragile Sergey Senozhatsky
2015-07-11  2:51 ` Sergey Senozhatsky
2015-07-11  2:51 ` [PATCH 1/2] mm/shrinker: do not NULL dereference uninitialized shrinker Sergey Senozhatsky
2015-07-11  2:51   ` Sergey Senozhatsky
2015-07-11  2:51 ` [PATCH 2/2] mm/shrinker: add init_shrinker() function Sergey Senozhatsky
2015-07-11  2:51   ` Sergey Senozhatsky
2015-07-11 10:02 ` [PATCH 0/2] mm/shrinker: make unregister_shrinker() less fragile Christoph Hellwig
2015-07-11 10:02   ` Christoph Hellwig
2015-07-12  2:47   ` Sergey Senozhatsky
2015-07-12  2:47     ` Sergey Senozhatsky
2015-07-13  6:33     ` Christoph Hellwig
2015-07-13  6:33       ` Christoph Hellwig
2015-07-13  6:52       ` Sergey Senozhatsky
2015-07-13  6:52         ` Sergey Senozhatsky
2015-07-13  9:03         ` Christoph Hellwig
2015-07-13  9:03           ` Christoph Hellwig
2015-07-13  9:34           ` Sergey Senozhatsky
2015-07-13  9:34             ` Sergey Senozhatsky
2015-07-14  7:17             ` Christoph Hellwig [this message]
2015-07-14  7:17               ` Christoph Hellwig

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=20150714071759.GD31117@infradead.org \
    --to=hch@infradead.org \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=sergey.senozhatsky.work@gmail.com \
    --cc=sergey.senozhatsky@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.