linux-hyperv.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Minchan Kim <minchan@kernel.org>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Christoph Hellwig <hch@lst.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>,
	x86@kernel.org, David Airlie <airlied@linux.ie>,
	Daniel Vetter <daniel@ffwll.ch>,
	Laura Abbott <labbott@redhat.com>,
	Sumit Semwal <sumit.semwal@linaro.org>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Nitin Gupta <ngupta@vflare.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Christophe Leroy <christophe.leroy@c-s.fr>,
	linuxppc-dev@lists.ozlabs.org, linux-hyperv@vger.kernel.org,
	dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
	linux-arch@vger.kernel.org, linux-mm@kvack.org,
	iommu@lists.linux-foundation.org,
	linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org,
	bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 10/28] mm: only allow page table mappings for built-in zsmalloc
Date: Fri, 10 Apr 2020 16:11:36 -0700	[thread overview]
Message-ID: <20200410231136.GA101325@google.com> (raw)
In-Reply-To: <20200410023845.GA2354@jagdpanzerIV.localdomain>

Hi Sergey,

On Fri, Apr 10, 2020 at 11:38:45AM +0900, Sergey Senozhatsky wrote:
> On (20/04/09 10:08), Minchan Kim wrote:
> > > > Even though I don't know how many usecase we have using zsmalloc as
> > > > module(I heard only once by dumb reason), it could affect existing
> > > > users. Thus, please include concrete explanation in the patch to
> > > > justify when the complain occurs.
> > > 
> > > The justification is 'we can unexport functions that have no sane reason
> > > of being exported in the first place'.
> > > 
> > > The Changelog pretty much says that.
> > 
> > Okay, I hope there is no affected user since this patch.
> > If there are someone, they need to provide sane reason why they want
> > to have zsmalloc as module.
> 
> I'm one of those who use zsmalloc as a module - mainly because I use zram
> as a compressing general purpose block device, not as a swap device.
> I create zram0, mkfs, mount, checkout and compile code, once done -
> umount, rmmod. This reduces the number of writes to SSD. Some people use
> tmpfs, but zram device(-s) can be much larger in size. That's a niche use
> case and I'm not against the patch.

It doesn't mean we couldn't use zsmalloc as module any longer. It means
we couldn't use zsmalloc as module with pgtable mapping whcih was little
bit faster on microbenchmark in some architecutre(However, I usually temped
to remove it since it had several problems). However, we could still use
zsmalloc as module as copy way instead of pgtable mapping. Thus, if someone
really want to rollback the feature, they should provide reasonable reason
why it doesn't work for them. "A little fast" wouldn't be enough to exports
deep internal to the module.

Thanks.

  reply	other threads:[~2020-04-10 23:11 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-08 11:58 decruft the vmalloc API Christoph Hellwig
2020-04-08 11:58 ` [PATCH 01/28] x86/hyperv: use vmalloc_exec for the hypercall page Christoph Hellwig
2020-04-09 15:52   ` Wei Liu
2020-04-10 20:40   ` Michael Kelley
2020-04-08 11:59 ` [PATCH 02/28] staging: android: ion: use vmap instead of vm_map_ram Christoph Hellwig
2020-04-08 13:27   ` Greg KH
2020-04-08 11:59 ` [PATCH 03/28] staging: media: ipu3: use vmap insted of reimplementing it Christoph Hellwig
2020-04-08 11:59 ` [PATCH 04/28] dma-mapping: " Christoph Hellwig
2020-04-08 11:59 ` [PATCH 05/28] powerpc: add an ioremap_phb helper Christoph Hellwig
2020-04-08 11:59 ` [PATCH 06/28] powerpc: remove __ioremap_at and __iounmap_at Christoph Hellwig
2020-04-08 11:59 ` [PATCH 07/28] mm: remove __get_vm_area Christoph Hellwig
2020-04-08 11:59 ` [PATCH 08/28] mm: unexport unmap_kernel_range_noflush Christoph Hellwig
2020-04-08 11:59 ` [PATCH 09/28] mm: rename CONFIG_PGTABLE_MAPPING to CONFIG_ZSMALLOC_PGTABLE_MAPPING Christoph Hellwig
2020-04-08 15:00   ` Randy Dunlap
2020-04-09 15:59   ` Minchan Kim
2020-04-08 11:59 ` [PATCH 10/28] mm: only allow page table mappings for built-in zsmalloc Christoph Hellwig
2020-04-08 15:01   ` Randy Dunlap
2020-04-08 15:12     ` Peter Zijlstra
2020-04-08 15:15       ` Matthew Wilcox
2020-04-08 15:36         ` Christoph Hellwig
2020-04-08 15:37           ` Randy Dunlap
2020-04-08 15:36         ` Randy Dunlap
2020-04-09 16:08   ` Minchan Kim
2020-04-09 16:50     ` Peter Zijlstra
2020-04-09 17:08       ` Minchan Kim
2020-04-10  2:38         ` Sergey Senozhatsky
2020-04-10 23:11           ` Minchan Kim [this message]
2020-04-11  7:20             ` Christoph Hellwig
2020-04-16 20:37               ` Minchan Kim
2020-04-08 11:59 ` [PATCH 11/28] mm: pass addr as unsigned long to vb_free Christoph Hellwig
2020-04-08 11:59 ` [PATCH 12/28] mm: remove vmap_page_range_noflush and vunmap_page_range Christoph Hellwig
2020-04-08 11:59 ` [PATCH 13/28] mm: rename vmap_page_range to map_kernel_range Christoph Hellwig
2020-04-08 11:59 ` [PATCH 14/28] mm: don't return the number of pages from map_kernel_range{,_noflush} Christoph Hellwig
2020-04-08 11:59 ` [PATCH 15/28] mm: remove map_vm_range Christoph Hellwig
2020-04-08 11:59 ` [PATCH 16/28] mm: remove unmap_vmap_area Christoph Hellwig
2020-04-08 11:59 ` [PATCH 17/28] mm: remove the prot argument from vm_map_ram Christoph Hellwig
2020-04-08 12:21   ` Peter Zijlstra
2020-04-08 12:23     ` Christoph Hellwig
2020-04-09  0:39   ` Gao Xiang
2020-04-08 11:59 ` [PATCH 18/28] mm: enforce that vmap can't map pages executable Christoph Hellwig
2020-04-08 12:38   ` Mark Rutland
2020-04-08 15:32     ` Christoph Hellwig
2020-04-08 11:59 ` [PATCH 19/28] gpu/drm: remove the powerpc hack in drm_legacy_sg_alloc Christoph Hellwig
2020-04-08 12:25   ` Daniel Vetter
2020-04-09  8:54     ` Benjamin Herrenschmidt
2020-04-09  9:41       ` Daniel Vetter
2020-04-09 14:19         ` Alex Deucher
2020-04-09 14:57           ` Daniel Vetter
2020-04-09 22:56         ` Benjamin Herrenschmidt
2020-04-10  8:11           ` Daniel Vetter
2020-04-09 11:46       ` Gerhard Pircher
2020-04-08 11:59 ` [PATCH 20/28] mm: remove the pgprot argument to __vmalloc Christoph Hellwig
2020-04-10 20:39   ` Michael Kelley
2020-04-08 11:59 ` [PATCH 21/28] mm: remove the prot argument to __vmalloc_node Christoph Hellwig
2020-04-08 11:59 ` [PATCH 22/28] mm: remove both instances of __vmalloc_node_flags Christoph Hellwig
2020-04-08 11:59 ` [PATCH 23/28] mm: remove __vmalloc_node_flags_caller Christoph Hellwig
2020-04-08 11:59 ` [PATCH 24/28] mm: switch the test_vmalloc module to use __vmalloc_node Christoph Hellwig
2020-04-08 11:59 ` [PATCH 25/28] mm: remove vmalloc_user_node_flags Christoph Hellwig
2020-04-09 22:25   ` Andrii Nakryiko
2020-04-13 20:03     ` Johannes Weiner
2020-04-08 11:59 ` [PATCH 26/28] arm64: use __vmalloc_node in arch_alloc_vmap_stack Christoph Hellwig
2020-04-08 12:18   ` Mark Rutland
2020-04-08 11:59 ` [PATCH 27/28] s390: use __vmalloc_node in alloc_vm_stack Christoph Hellwig
2020-04-08 13:33   ` Christian Borntraeger
2020-04-08 11:59 ` [PATCH 28/28] s390: use __vmalloc_node in stack_alloc Christoph Hellwig
2020-04-08 13:44   ` Christian Borntraeger
2020-04-08 12:25 ` decruft the vmalloc API Peter Zijlstra
     [not found] ` <20200408124833.13032-1-hdanton@sina.com>
2020-04-08 15:40   ` [PATCH 02/28] staging: android: ion: use vmap instead of vm_map_ram Christoph Hellwig
2020-04-08 16:03 ` decruft the vmalloc API Russell King - ARM Linux admin
2020-04-08 16:07   ` 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=20200410231136.GA101325@google.com \
    --to=minchan@kernel.org \
    --cc=airlied@linux.ie \
    --cc=akpm@linux-foundation.org \
    --cc=bpf@vger.kernel.org \
    --cc=christophe.leroy@c-s.fr \
    --cc=daniel@ffwll.ch \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=haiyangz@microsoft.com \
    --cc=hch@lst.de \
    --cc=iommu@lists.linux-foundation.org \
    --cc=kys@microsoft.com \
    --cc=labbott@redhat.com \
    --cc=linaro-mm-sig@lists.linaro.org \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-hyperv@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-s390@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=ngupta@vflare.org \
    --cc=peterz@infradead.org \
    --cc=robin.murphy@arm.com \
    --cc=sakari.ailus@linux.intel.com \
    --cc=sergey.senozhatsky@gmail.com \
    --cc=sthemmin@microsoft.com \
    --cc=sumit.semwal@linaro.org \
    --cc=wei.liu@kernel.org \
    --cc=x86@kernel.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;
as well as URLs for NNTP newsgroup(s).