From: Matthew Wilcox <willy@infradead.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: jack@suse.cz, linux-nvdimm@lists.01.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, hch@lst.de
Subject: Re: [PATCH v2 05/14] mm, memremap: Up-level foreach_order_pgoff()
Date: Mon, 16 Jul 2018 14:00:14 -0700 [thread overview]
Message-ID: <20180716210014.GA1607@bombadil.infradead.org> (raw)
In-Reply-To: <153176044796.12695.10692625606054072713.stgit@dwillia2-desk3.amr.corp.intel.com>
On Mon, Jul 16, 2018 at 10:00:48AM -0700, Dan Williams wrote:
> The foreach_order_pgoff() helper takes advantage of the ability to
> insert multi-order entries into a radix. It is currently used by
> devm_memremap_pages() to minimize the number of entries in the pgmap
> radix. Instead of dividing a range by a constant power-of-2 sized unit
> and inserting an entry for each unit, it determines the maximum
> power-of-2 sized entry (subject to alignment offset) that can be
> inserted at each iteration.
>
> Up-level this helper so it can be used for populating other radix
> instances. For example asynchronous-memmap-initialization-thread lookups
> arriving in a follow on change.
Hopefully by the time you're back, I'll have this code replaced with
the XArray. Here's my proposed API:
old = xa_store_range(xa, first, last, ptr, GFP_KERNEL);
and then you'd simply use xa_for_each() as an iterator. You'd do one
iteration for each range in the XArray, not for each entry occupied.
So there's a difference between:
xa_store(xa, 1, ptr, GFP_KERNEL);
xa_store(xa, 2, ptr, GFP_KERNEL);
xa_store(xa, 3, ptr, GFP_KERNEL);
and
xa_store_range(xa, 1, 3, ptr, GFP_KERNEL);
index = 0; i = 0;
xa_for_each(xa, p, index, ULONG_MAX, XA_PRESENT)
i++;
will return i = 3 for the first case and i = 1 for the second.
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next prev parent reply other threads:[~2018-07-16 21:00 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-16 17:00 [PATCH v2 00/14] mm: Asynchronous + multithreaded memmap init for ZONE_DEVICE Dan Williams
2018-07-16 17:00 ` [PATCH v2 01/14] mm: Plumb dev_pagemap instead of vmem_altmap to memmap_init_zone() Dan Williams
2018-07-16 17:00 ` [PATCH v2 02/14] mm: Enable asynchronous __add_pages() and vmemmap_populate_hugepages() Dan Williams
2018-07-16 17:00 ` [PATCH v2 03/14] mm: Teach memmap_init_zone() to initialize ZONE_DEVICE pages Dan Williams
2018-07-16 17:00 ` [PATCH v2 04/14] mm: Multithread ZONE_DEVICE initialization Dan Williams
2018-07-16 17:00 ` [PATCH v2 05/14] mm, memremap: Up-level foreach_order_pgoff() Dan Williams
2018-07-16 21:00 ` Matthew Wilcox [this message]
2018-07-16 17:00 ` [PATCH v2 06/14] mm: Allow an external agent to coordinate memmap initialization Dan Williams
2018-07-16 17:00 ` [PATCH v2 07/14] libnvdimm, pmem: Allow a NULL-pfn to ->direct_access() Dan Williams
2018-07-16 17:01 ` [PATCH v2 08/14] tools/testing/nvdimm: " Dan Williams
2018-07-16 17:01 ` [PATCH v2 09/14] s390, dcssblk: " Dan Williams
2018-07-16 17:01 ` [PATCH v2 10/14] filesystem-dax: Do not request a pfn when not required Dan Williams
2018-07-16 17:01 ` [PATCH v2 11/14] filesystem-dax: Make mount time pfn validation a debug check Dan Williams
2018-07-16 17:01 ` [PATCH v2 12/14] libnvdimm, pmem: Initialize the memmap in the background Dan Williams
2018-07-16 17:01 ` [PATCH v2 13/14] device-dax: " Dan Williams
2018-07-16 17:01 ` [PATCH v2 14/14] libnvdimm, namespace: Publish page structure init state / control Dan Williams
2018-07-16 19:12 ` [PATCH v2 00/14] mm: Asynchronous + multithreaded memmap init for ZONE_DEVICE Pavel Tatashin
2018-07-16 20:30 ` Dan Williams
2018-07-17 14:46 ` Pavel Tatashin
2018-07-17 15:50 ` Michal Hocko
2018-07-17 17:32 ` Dan Williams
2018-07-18 12:05 ` Michal Hocko
2018-07-19 18:41 ` Dave Hansen
2018-07-23 11:09 ` Michal Hocko
2018-07-23 16:15 ` Dave Hansen
2018-07-24 7:29 ` Michal Hocko
2018-09-10 19:06 ` Dan Williams
2018-09-10 19:47 ` Alexander Duyck
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