From: Mikulas Patocka <mpatocka@redhat.com>
To: Christopher Lameter <cl@linux.com>
Cc: Vlastimil Babka <vbabka@suse.cz>,
Mike Snitzer <snitzer@redhat.com>,
Matthew Wilcox <willy@infradead.org>,
Pekka Enberg <penberg@kernel.org>,
linux-mm@kvack.org, dm-devel@redhat.com,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: slab: introduce the flag SLAB_MINIMIZE_WASTE
Date: Tue, 17 Apr 2018 14:53:45 -0400 (EDT) [thread overview]
Message-ID: <alpine.LRH.2.02.1804171453190.26973@file01.intranet.prod.int.rdu2.redhat.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1804170939420.17557@nuc-kabylake>
On Tue, 17 Apr 2018, Christopher Lameter wrote:
> On Mon, 16 Apr 2018, Mikulas Patocka wrote:
>
> > dm-bufio deals gracefully with allocation failure, because it preallocates
> > some buffers with vmalloc, but other subsystems may not deal with it and
> > they cound return ENOMEM randomly or misbehave in other ways. So, the
> > "SLAB_MINIMIZE_WASTE" flag is also saying that the allocation may fail and
> > the caller is prepared to deal with it.
> >
> > The slub subsystem does actual fallback to low-order when the allocation
> > fails (it allows different order for each slab in the same cache), but
> > slab doesn't fallback and you get NULL if higher-order allocation fails.
> > So, SLAB_MINIMIZE_WASTE is needed for slab because it will just randomly
> > fail with higher order.
>
> Fix Slab instead of adding a flag that is only useful for one allocator?
Slab assumes that all slabs have the same order, so it's not so easy to
fix it.
Mikulas
WARNING: multiple messages have this Message-ID (diff)
From: Mikulas Patocka <mpatocka@redhat.com>
To: Christopher Lameter <cl@linux.com>
Cc: Mike Snitzer <snitzer@redhat.com>,
linux-kernel@vger.kernel.org,
Matthew Wilcox <willy@infradead.org>,
Pekka Enberg <penberg@kernel.org>,
linux-mm@kvack.org, dm-devel@redhat.com,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: slab: introduce the flag SLAB_MINIMIZE_WASTE
Date: Tue, 17 Apr 2018 14:53:45 -0400 (EDT) [thread overview]
Message-ID: <alpine.LRH.2.02.1804171453190.26973@file01.intranet.prod.int.rdu2.redhat.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1804170939420.17557@nuc-kabylake>
On Tue, 17 Apr 2018, Christopher Lameter wrote:
> On Mon, 16 Apr 2018, Mikulas Patocka wrote:
>
> > dm-bufio deals gracefully with allocation failure, because it preallocates
> > some buffers with vmalloc, but other subsystems may not deal with it and
> > they cound return ENOMEM randomly or misbehave in other ways. So, the
> > "SLAB_MINIMIZE_WASTE" flag is also saying that the allocation may fail and
> > the caller is prepared to deal with it.
> >
> > The slub subsystem does actual fallback to low-order when the allocation
> > fails (it allows different order for each slab in the same cache), but
> > slab doesn't fallback and you get NULL if higher-order allocation fails.
> > So, SLAB_MINIMIZE_WASTE is needed for slab because it will just randomly
> > fail with higher order.
>
> Fix Slab instead of adding a flag that is only useful for one allocator?
Slab assumes that all slabs have the same order, so it's not so easy to
fix it.
Mikulas
next prev parent reply other threads:[~2018-04-17 18:54 UTC|newest]
Thread overview: 109+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-20 17:25 [PATCH] slab: introduce the flag SLAB_MINIMIZE_WASTE Mikulas Patocka
2018-03-20 17:35 ` Matthew Wilcox
2018-03-20 17:35 ` Matthew Wilcox
2018-03-20 17:54 ` Christopher Lameter
2018-03-20 17:54 ` Christopher Lameter
2018-03-20 19:22 ` Mikulas Patocka
2018-03-20 19:22 ` Mikulas Patocka
2018-03-20 20:42 ` Christopher Lameter
2018-03-20 20:42 ` Christopher Lameter
2018-03-20 22:02 ` Mikulas Patocka
2018-03-20 22:02 ` Mikulas Patocka
2018-03-21 15:35 ` Christopher Lameter
2018-03-21 15:35 ` Christopher Lameter
2018-03-21 16:25 ` Mikulas Patocka
2018-03-21 16:25 ` Mikulas Patocka
2018-03-21 17:10 ` Matthew Wilcox
2018-03-21 17:10 ` Matthew Wilcox
2018-03-21 17:30 ` Christopher Lameter
2018-03-21 17:30 ` Christopher Lameter
2018-03-21 17:39 ` Christopher Lameter
2018-03-21 17:39 ` Christopher Lameter
2018-03-21 17:49 ` Matthew Wilcox
2018-03-21 17:49 ` Matthew Wilcox
2018-03-21 18:01 ` Christopher Lameter
2018-03-21 18:01 ` Christopher Lameter
2018-03-21 18:23 ` Mikulas Patocka
2018-03-21 18:23 ` Mikulas Patocka
2018-03-21 18:40 ` Christopher Lameter
2018-03-21 18:40 ` Christopher Lameter
2018-03-21 18:55 ` Mikulas Patocka
2018-03-21 18:55 ` Mikulas Patocka
2018-03-21 18:55 ` Matthew Wilcox
2018-03-21 18:55 ` Matthew Wilcox
2018-03-21 18:58 ` Christopher Lameter
2018-03-21 18:58 ` Christopher Lameter
2018-03-21 19:25 ` Mikulas Patocka
2018-03-21 19:25 ` Mikulas Patocka
2018-03-21 18:36 ` Mikulas Patocka
2018-03-21 18:36 ` Mikulas Patocka
2018-03-21 18:57 ` Christopher Lameter
2018-03-21 18:57 ` Christopher Lameter
2018-03-21 19:19 ` Mikulas Patocka
2018-03-21 19:19 ` Mikulas Patocka
2018-03-21 20:09 ` Christopher Lameter
2018-03-21 20:09 ` Christopher Lameter
2018-03-21 20:37 ` Mikulas Patocka
2018-03-21 20:37 ` Mikulas Patocka
2018-03-23 15:10 ` Christopher Lameter
2018-03-23 15:10 ` Christopher Lameter
2018-03-23 15:31 ` Mikulas Patocka
2018-03-23 15:31 ` Mikulas Patocka
2018-03-23 15:48 ` Christopher Lameter
2018-03-23 15:48 ` Christopher Lameter
2018-04-13 9:22 ` Vlastimil Babka
2018-04-13 9:22 ` Vlastimil Babka
2018-04-13 15:10 ` Mike Snitzer
2018-04-13 15:10 ` Mike Snitzer
2018-04-16 12:38 ` Vlastimil Babka
2018-04-16 12:38 ` Vlastimil Babka
2018-04-16 14:27 ` Mike Snitzer
2018-04-16 14:27 ` Mike Snitzer
2018-04-16 14:37 ` Mikulas Patocka
2018-04-16 14:37 ` Mikulas Patocka
2018-04-16 14:46 ` Mike Snitzer
2018-04-16 14:46 ` Mike Snitzer
2018-04-16 14:57 ` Mikulas Patocka
2018-04-16 14:57 ` Mikulas Patocka
2018-04-16 15:18 ` Christopher Lameter
2018-04-16 15:18 ` Christopher Lameter
2018-04-16 15:25 ` Mikulas Patocka
2018-04-16 15:25 ` Mikulas Patocka
2018-04-16 15:45 ` Christopher Lameter
2018-04-16 15:45 ` Christopher Lameter
2018-04-16 19:36 ` Mikulas Patocka
2018-04-16 19:36 ` Mikulas Patocka
2018-04-16 19:53 ` Vlastimil Babka
2018-04-16 21:01 ` Mikulas Patocka
2018-04-17 14:40 ` Christopher Lameter
2018-04-17 18:53 ` Mikulas Patocka [this message]
2018-04-17 18:53 ` Mikulas Patocka
2018-04-17 21:42 ` Christopher Lameter
2018-04-17 14:49 ` Christopher Lameter
2018-04-17 14:49 ` Christopher Lameter
2018-04-17 14:47 ` Christopher Lameter
2018-04-17 14:47 ` Christopher Lameter
2018-04-16 19:32 ` [PATCH RESEND] " Mikulas Patocka
2018-04-17 14:45 ` Christopher Lameter
2018-04-17 16:16 ` Vlastimil Babka
2018-04-17 16:38 ` Christopher Lameter
2018-04-17 19:09 ` Mikulas Patocka
2018-04-17 17:26 ` Mikulas Patocka
2018-04-17 19:13 ` Vlastimil Babka
2018-04-17 19:06 ` Mikulas Patocka
2018-04-17 19:06 ` Mikulas Patocka
2018-04-18 14:55 ` Christopher Lameter
2018-04-25 21:04 ` Mikulas Patocka
2018-04-25 23:24 ` Mikulas Patocka
2018-04-26 19:01 ` Christopher Lameter
2018-04-26 21:09 ` Mikulas Patocka
2018-04-27 16:41 ` Christopher Lameter
2018-04-27 19:19 ` Mikulas Patocka
2018-06-13 17:01 ` Mikulas Patocka
2018-06-13 18:16 ` Christoph Hellwig
2018-06-13 18:53 ` Mikulas Patocka
2018-04-26 18:51 ` Christopher Lameter
2018-04-16 19:38 ` Vlastimil Babka
2018-04-16 19:38 ` Vlastimil Babka
2018-04-16 21:04 ` Mikulas Patocka
2018-04-16 21:04 ` Mikulas Patocka
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=alpine.LRH.2.02.1804171453190.26973@file01.intranet.prod.int.rdu2.redhat.com \
--to=mpatocka@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=cl@linux.com \
--cc=dm-devel@redhat.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=penberg@kernel.org \
--cc=rientjes@google.com \
--cc=snitzer@redhat.com \
--cc=vbabka@suse.cz \
--cc=willy@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 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.