From: Wei Yang <richardw.yang@linux.intel.com>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Segher Boessenkool <segher@kernel.crashing.org>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>,
Oscar Salvador <osalvador@suse.de>, Baoquan He <bhe@redhat.com>,
Wei Yang <richardw.yang@linux.intel.com>
Subject: Re: [PATCH v1] mm/memory_hotplug: Easier calculation to get pages to next section boundary
Date: Thu, 6 Feb 2020 07:19:45 +0800 [thread overview]
Message-ID: <20200205231945.GB28446@richard> (raw)
In-Reply-To: <20200205135251.37488-1-david@redhat.com>
On Wed, Feb 05, 2020 at 02:52:51PM +0100, David Hildenbrand wrote:
>Let's use a calculation that's easier to understand and calculates the
>same result. Reusing existing macros makes this look nicer.
>
>We always want to have the number of pages (> 0) to the next section
>boundary, starting from the current pfn.
>
>Suggested-by: Segher Boessenkool <segher@kernel.crashing.org>
>Cc: Andrew Morton <akpm@linux-foundation.org>
>Cc: Michal Hocko <mhocko@kernel.org>
>Cc: Oscar Salvador <osalvador@suse.de>
>Cc: Baoquan He <bhe@redhat.com>
>Cc: Wei Yang <richardw.yang@linux.intel.com>
>Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Wei Yang <richardw.yang@linux.intel.com>
BTW, I got one question about hotplug size requirement.
I thought the hotplug range should be section size aligned, while taking a
look into current code function check_hotplug_memory_range() guard the range.
This function says the range should be block_size aligned. And if I am
correct, block size on x86 should be in the range
[MIN_MEMORY_BLOCK_SIZE, MEM_SIZE_FOR_LARGE_BLOCK]
And MIN_MEMORY_BLOCK_SIZE is section size.
Seems currently we support subsection hotplug? Then how a subsection range got
hotplug? Or this patch is a pre-requisite?
>---
> mm/memory_hotplug.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
>diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>index 0a54ffac8c68..c30191183c04 100644
>--- a/mm/memory_hotplug.c
>+++ b/mm/memory_hotplug.c
>@@ -528,7 +528,8 @@ void __remove_pages(unsigned long pfn, unsigned long nr_pages,
> for (; pfn < end_pfn; pfn += cur_nr_pages) {
> cond_resched();
> /* Select all remaining pages up to the next section boundary */
>- cur_nr_pages = min(end_pfn - pfn, -(pfn | PAGE_SECTION_MASK));
>+ cur_nr_pages = min(end_pfn - pfn,
>+ SECTION_ALIGN_UP(pfn + 1) - pfn);
> __remove_section(pfn, cur_nr_pages, map_offset, altmap);
> map_offset = 0;
> }
>--
>2.24.1
--
Wei Yang
Help you, Help me
next prev parent reply other threads:[~2020-02-05 23:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-05 13:52 [PATCH v1] mm/memory_hotplug: Easier calculation to get pages to next section boundary David Hildenbrand
2020-02-05 23:19 ` Wei Yang [this message]
2020-02-05 23:50 ` Wei Yang
2020-02-06 0:13 ` Baoquan He
2020-02-06 0:37 ` Baoquan He
2020-02-06 2:26 ` Wei Yang
2020-02-06 2:48 ` Baoquan He
2020-02-06 4:34 ` Wei Yang
2020-02-06 4:39 ` Baoquan He
2020-02-06 9:01 ` David Hildenbrand
2020-02-06 11:38 ` Wei Yang
2020-02-06 1:46 ` Baoquan He
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