All of lore.kernel.org
 help / color / mirror / Atom feed
From: Oscar Salvador <osalvador@suse.de>
To: Dan Williams <dan.j.williams@intel.com>, akpm@linux-foundation.org
Cc: Michal Hocko <mhocko@suse.com>,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, Qian Cai <cai@lca.pw>,
	Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH v10 03/13] mm/sparsemem: Add helpers track active portions of a section at boot
Date: Mon, 24 Jun 2019 19:57:55 +0200	[thread overview]
Message-ID: <1561399075.3073.6.camel@suse.de> (raw)
In-Reply-To: <156092350874.979959.18185938451405518285.stgit@dwillia2-desk3.amr.corp.intel.com>

On Tue, 2019-06-18 at 22:51 -0700, Dan Williams wrote:
> Prepare for hot{plug,remove} of sub-ranges of a section by tracking a
> sub-section active bitmask, each bit representing a PMD_SIZE span of
> the
> architecture's memory hotplug section size.
> 
> The implications of a partially populated section is that pfn_valid()
> needs to go beyond a valid_section() check and either determine that
> the
> section is an "early section", or read the sub-section active ranges
> from the bitmask. The expectation is that the bitmask
> (subsection_map)
> fits in the same cacheline as the valid_section() / early_section()
> data, so the incremental performance overhead to pfn_valid() should
> be
> negligible.
> 
> The rationale for using early_section() to short-ciruit the
> subsection_map check is that there are legacy code paths that use
> pfn_valid() at section granularity before validating the pfn against
> pgdat data. So, the early_section() check allows those traditional
> assumptions to persist while also permitting subsection_map to tell
> the
> truth for purposes of populating the unused portions of early
> sections
> with PMEM and other ZONE_DEVICE mappings.
> 
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Logan Gunthorpe <logang@deltatee.com>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
> Reported-by: Qian Cai <cai@lca.pw>
> Tested-by: Jane Chu <jane.chu@oracle.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Reviewed-by: Oscar Salvador <osalvador@suse.de>

-- 
Oscar Salvador
SUSE L3
_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

WARNING: multiple messages have this Message-ID (diff)
From: Oscar Salvador <osalvador@suse.de>
To: Dan Williams <dan.j.williams@intel.com>, akpm@linux-foundation.org
Cc: Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
	Logan Gunthorpe <logang@deltatee.com>,
	Pavel Tatashin <pasha.tatashin@soleen.com>, Qian Cai <cai@lca.pw>,
	 Jane Chu <jane.chu@oracle.com>,
	linux-mm@kvack.org, linux-nvdimm@lists.01.org,
	 linux-kernel@vger.kernel.org
Subject: Re: [PATCH v10 03/13] mm/sparsemem: Add helpers track active portions of a section at boot
Date: Mon, 24 Jun 2019 19:57:55 +0200	[thread overview]
Message-ID: <1561399075.3073.6.camel@suse.de> (raw)
In-Reply-To: <156092350874.979959.18185938451405518285.stgit@dwillia2-desk3.amr.corp.intel.com>

On Tue, 2019-06-18 at 22:51 -0700, Dan Williams wrote:
> Prepare for hot{plug,remove} of sub-ranges of a section by tracking a
> sub-section active bitmask, each bit representing a PMD_SIZE span of
> the
> architecture's memory hotplug section size.
> 
> The implications of a partially populated section is that pfn_valid()
> needs to go beyond a valid_section() check and either determine that
> the
> section is an "early section", or read the sub-section active ranges
> from the bitmask. The expectation is that the bitmask
> (subsection_map)
> fits in the same cacheline as the valid_section() / early_section()
> data, so the incremental performance overhead to pfn_valid() should
> be
> negligible.
> 
> The rationale for using early_section() to short-ciruit the
> subsection_map check is that there are legacy code paths that use
> pfn_valid() at section granularity before validating the pfn against
> pgdat data. So, the early_section() check allows those traditional
> assumptions to persist while also permitting subsection_map to tell
> the
> truth for purposes of populating the unused portions of early
> sections
> with PMEM and other ZONE_DEVICE mappings.
> 
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Logan Gunthorpe <logang@deltatee.com>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
> Reported-by: Qian Cai <cai@lca.pw>
> Tested-by: Jane Chu <jane.chu@oracle.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Reviewed-by: Oscar Salvador <osalvador@suse.de>

-- 
Oscar Salvador
SUSE L3


  reply	other threads:[~2019-06-24 17:57 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-19  5:51 [PATCH v10 00/13] mm: Sub-section memory hotplug support Dan Williams
2019-06-19  5:51 ` Dan Williams
2019-06-19  5:51 ` [PATCH v10 01/13] mm/sparsemem: Introduce struct mem_section_usage Dan Williams
2019-06-19  5:51   ` Dan Williams
2019-06-19  5:51 ` [PATCH v10 02/13] mm/sparsemem: Introduce a SECTION_IS_EARLY flag Dan Williams
2019-06-19  5:51   ` Dan Williams
2019-06-24 17:54   ` Oscar Salvador
2019-06-24 17:54     ` Oscar Salvador
2019-06-19  5:51 ` [PATCH v10 03/13] mm/sparsemem: Add helpers track active portions of a section at boot Dan Williams
2019-06-19  5:51   ` Dan Williams
2019-06-24 17:57   ` Oscar Salvador [this message]
2019-06-24 17:57     ` Oscar Salvador
2019-06-19  5:51 ` [PATCH v10 04/13] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal Dan Williams
2019-06-19  5:51   ` Dan Williams
2019-06-19  5:52 ` [PATCH v10 05/13] mm/sparsemem: Convert kmalloc_section_memmap() to populate_section_memmap() Dan Williams
2019-06-19  5:52   ` Dan Williams
2019-06-24 18:00   ` Oscar Salvador
2019-06-24 18:00     ` Oscar Salvador
2019-06-19  5:52 ` [PATCH v10 06/13] mm/hotplug: Kill is_dev_zone() usage in __remove_pages() Dan Williams
2019-06-19  5:52   ` Dan Williams
2019-06-19  5:52 ` [PATCH v10 07/13] mm: Kill is_dev_zone() helper Dan Williams
2019-06-19  5:52   ` Dan Williams
2019-06-19  5:52 ` [PATCH v10 08/13] mm/sparsemem: Prepare for sub-section ranges Dan Williams
2019-06-19  5:52   ` Dan Williams
2019-06-20 10:31   ` David Hildenbrand
2019-06-20 10:31     ` David Hildenbrand
2019-06-20 16:19     ` Dan Williams
2019-06-20 16:35       ` David Hildenbrand
2019-06-20 16:35         ` David Hildenbrand
2019-06-20 16:56         ` Dan Williams
2019-06-20 16:56           ` Dan Williams
2019-06-24 18:05   ` Oscar Salvador
2019-06-24 18:05     ` Oscar Salvador
2019-06-19  5:52 ` [PATCH v10 09/13] mm/sparsemem: Support sub-section hotplug Dan Williams
2019-06-19  5:52   ` Dan Williams
2019-06-24 20:45   ` Oscar Salvador
2019-06-24 20:45     ` Oscar Salvador
2019-06-19  5:52 ` [PATCH v10 10/13] mm: Document ZONE_DEVICE memory-model implications Dan Williams
2019-06-19  5:52   ` Dan Williams
2019-06-20 12:30   ` Mike Rapoport
2019-06-20 12:30     ` Mike Rapoport
2019-06-19  5:52 ` [PATCH v10 11/13] mm/devm_memremap_pages: Enable sub-section remap Dan Williams
2019-06-19  5:52   ` Dan Williams
2019-06-19  5:52 ` [PATCH v10 12/13] libnvdimm/pfn: Fix fsdax-mode namespace info-block zero-fields Dan Williams
2019-06-19  5:52   ` Dan Williams
2019-06-19 16:30   ` Aneesh Kumar K.V
2019-06-19 17:06     ` Dan Williams
2019-06-19 17:06       ` Dan Williams
2019-06-19  5:52 ` [PATCH v10 13/13] libnvdimm/pfn: Stop padding pmem namespaces to section alignment Dan Williams
2019-06-19  5:52   ` Dan Williams
2019-06-20 12:30 ` [PATCH v10 00/13] mm: Sub-section memory hotplug support Aneesh Kumar K.V
2019-06-20 12:30   ` Aneesh Kumar K.V
2019-06-20 16:30   ` Dan Williams
2019-06-20 16:30     ` Dan Williams
2019-06-20 17:00 ` Oscar Salvador
2019-06-20 17:00   ` Oscar Salvador

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=1561399075.3073.6.camel@suse.de \
    --to=osalvador@suse.de \
    --cc=akpm@linux-foundation.org \
    --cc=cai@lca.pw \
    --cc=dan.j.williams@intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=mhocko@suse.com \
    --cc=pasha.tatashin@soleen.com \
    --cc=vbabka@suse.cz \
    /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.