From: Michal Hocko <mhocko@kernel.org>
To: Arun KS <arunks@codeaurora.org>
Cc: kys@microsoft.com, haiyangz@microsoft.com,
sthemmin@microsoft.com, boris.ostrovsky@oracle.com,
jgross@suse.com, akpm@linux-foundation.org,
dan.j.williams@intel.com, vbabka@suse.cz, iamjoonsoo.kim@lge.com,
gregkh@linuxfoundation.org, osalvador@suse.de, malat@debian.org,
kirill.shutemov@linux.intel.com, jrdr.linux@gmail.com,
yasu.isimatu@gmail.com, mgorman@techsingularity.net,
aaron.lu@intel.com, devel@linuxdriverproject.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
xen-devel@lists.xenproject.org, vatsa@codeaurora.org,
vinmenon@codeaurora.org, getarunks@gmail.com
Subject: Re: [PATCH v4] memory_hotplug: Free pages as higher order
Date: Thu, 4 Oct 2018 16:51:08 +0200 [thread overview]
Message-ID: <20181004145108.GH22173@dhcp22.suse.cz> (raw)
In-Reply-To: <1538573979-28365-1-git-send-email-arunks@codeaurora.org>
On Wed 03-10-18 19:09:39, Arun KS wrote:
[...]
> +static int online_pages_blocks(unsigned long start, unsigned long nr_pages)
> +{
> + unsigned long end = start + nr_pages;
> + int order, ret, onlined_pages = 0;
> +
> + while (start < end) {
> + order = min(MAX_ORDER - 1UL, __ffs(start));
> +
> + while (start + (1UL << order) > end)
> + order--;
this really made me scratch my head. Wouldn't it be much simpler to do
the following?
order = min(MAX_ORDER - 1, get_order(end - start))?
> +
> + ret = (*online_page_callback)(pfn_to_page(start), order);
> + if (!ret)
> + onlined_pages += (1UL << order);
> + else if (ret > 0)
> + onlined_pages += ret;
> +
> + start += (1UL << order);
> + }
> + return onlined_pages;
> }
[...]
> -static void __init __free_pages_boot_core(struct page *page, unsigned int order)
> +void __free_pages_core(struct page *page, unsigned int order)
> {
> unsigned int nr_pages = 1 << order;
> struct page *p = page;
> unsigned int loop;
>
> - prefetchw(p);
> - for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
> - prefetchw(p + 1);
> + for (loop = 0; loop < nr_pages; loop++, p++) {
> __ClearPageReserved(p);
> set_page_count(p, 0);
> }
> - __ClearPageReserved(p);
> - set_page_count(p, 0);
>
> page_zone(page)->managed_pages += nr_pages;
> set_page_refcounted(page);
I think this is wort a separate patch as it is unrelated to the patch.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-10-04 14:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-03 13:39 [PATCH v4] memory_hotplug: Free pages as higher order Arun KS
2018-10-04 14:51 ` Michal Hocko [this message]
2018-10-05 7:24 ` Arun KS
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