From: David Hildenbrand <david@redhat.com>
To: Alexander Duyck <alexander.duyck@gmail.com>,
kvm@vger.kernel.org, mst@redhat.com,
linux-kernel@vger.kernel.org, willy@infradead.org,
mhocko@kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org,
mgorman@techsingularity.net, vbabka@suse.cz
Cc: yang.zhang.wz@gmail.com, nitesh@redhat.com,
konrad.wilk@oracle.com, pagupta@redhat.com, riel@surriel.com,
lcapitulino@redhat.com, dave.hansen@intel.com,
wei.w.wang@intel.com, aarcange@redhat.com, pbonzini@redhat.com,
dan.j.williams@intel.com, alexander.h.duyck@linux.intel.com,
osalvador@suse.de
Subject: Re: [PATCH v15 3/7] mm: Add function __putback_isolated_page
Date: Mon, 16 Dec 2019 12:36:14 +0100 [thread overview]
Message-ID: <cb49bbc7-b0c0-65cc-1d9d-a3aaef075650@redhat.com> (raw)
In-Reply-To: <20191205162230.19548.70198.stgit@localhost.localdomain>
[...]
> +/**
> + * __putback_isolated_page - Return a now-isolated page back where we got it
> + * @page: Page that was isolated
> + * @order: Order of the isolated page
> + *
> + * This function is meant to return a page pulled from the free lists via
> + * __isolate_free_page back to the free lists they were pulled from.
> + */
> +void __putback_isolated_page(struct page *page, unsigned int order)
> +{
> + struct zone *zone = page_zone(page);
> + unsigned long pfn;
> + unsigned int mt;
> +
> + /* zone lock should be held when this function is called */
> + lockdep_assert_held(&zone->lock);
> +
> + pfn = page_to_pfn(page);
> + mt = get_pfnblock_migratetype(page, pfn);
IMHO get_pageblock_migratetype() would be nicer - I guess the compiler
will optimize out the double page_to_pfn().
> +
> + /* Return isolated page to tail of freelist. */
> + __free_one_page(page, pfn, zone, order, mt);
> +}
> +
> /*
> * Update NUMA hit/miss statistics
> *
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index 04ee1663cdbe..d93d2be0070f 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -134,13 +134,11 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
> __mod_zone_freepage_state(zone, nr_pages, migratetype);
> }
> set_pageblock_migratetype(page, migratetype);
> + if (isolated_page)
> + __putback_isolated_page(page, order);
> zone->nr_isolate_pageblock--;
> out:
> spin_unlock_irqrestore(&zone->lock, flags);
> - if (isolated_page) {
> - post_alloc_hook(page, order, __GFP_MOVABLE);
> - __free_pages(page, order);
> - }
So If I get it right:
post_alloc_hook() does quite some stuff like
- arch_alloc_page(page, order);
- kernel_map_pages(page, 1 << order, 1)
- kasan_alloc_pages()
- kernel_poison_pages(1)
- set_page_owner()
Which free_pages_prepare() will undo, like
- reset_page_owner()
- kernel_poison_pages(0)
- arch_free_page()
- kernel_map_pages()
- kasan_free_nondeferred_pages()
Both would be skipped now - which sounds like the right thing to do IMHO
(and smells like quite a performance improvement). I haven't verified if
actually everything we skip in free_pages_prepare() is safe (I think it
is, it seems to be mostly relevant for actually used/allocated pages).
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2019-12-16 11:36 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-05 16:22 [PATCH v15 0/7] mm / virtio: Provide support for free page reporting Alexander Duyck
2019-12-05 16:22 ` [PATCH v15 1/7] mm: Adjust shuffle code to allow for future coalescing Alexander Duyck
2019-12-05 16:22 ` [PATCH v15 2/7] mm: Use zone and order instead of free area in free_list manipulators Alexander Duyck
2019-12-05 16:22 ` [PATCH v15 3/7] mm: Add function __putback_isolated_page Alexander Duyck
2019-12-16 11:36 ` David Hildenbrand [this message]
2019-12-16 16:22 ` Alexander Duyck
2019-12-17 10:58 ` David Hildenbrand
2019-12-17 16:26 ` Alexander Duyck
2019-12-17 17:24 ` David Hildenbrand
2019-12-17 18:24 ` Alexander Duyck
2019-12-17 18:46 ` David Hildenbrand
2019-12-17 21:50 ` Alexander Duyck
2019-12-05 16:22 ` [PATCH v15 4/7] mm: Introduce Reported pages Alexander Duyck
2019-12-16 10:17 ` Nitesh Narayan Lal
2019-12-16 16:28 ` Alexander Duyck
2019-12-17 8:55 ` Nitesh Narayan Lal
2019-12-17 16:31 ` Alexander Duyck
2019-12-18 7:31 ` Mel Gorman
2019-12-16 11:44 ` Nitesh Narayan Lal
2019-12-16 16:10 ` Alexander Duyck
2019-12-05 16:22 ` [PATCH v15 5/7] virtio-balloon: Pull page poisoning config out of free page hinting Alexander Duyck
2019-12-13 7:03 ` Michael S. Tsirkin
2019-12-05 16:22 ` [PATCH v15 6/7] virtio-balloon: Add support for providing free page reports to host Alexander Duyck
2019-12-13 7:08 ` Michael S. Tsirkin
2019-12-13 16:35 ` Alexander Duyck
2019-12-15 9:29 ` Michael S. Tsirkin
2019-12-13 10:15 ` David Hildenbrand
2019-12-13 16:37 ` Alexander Duyck
2019-12-05 16:23 ` [PATCH v15 7/7] mm: Add free page reporting documentation Alexander Duyck
2019-12-05 16:24 ` [PATCH v15 QEMU 1/3] virtio-ballon: Implement support for page poison tracking feature Alexander Duyck
2019-12-05 16:24 ` [PATCH v15 QEMU 2/3] virtio-balloon: Add bit to notify guest of unused page reporting Alexander Duyck
2019-12-05 16:24 ` [PATCH v15 QEMU 3/3] virtio-balloon: Provide a interface for " Alexander Duyck
2019-12-05 16:26 ` [PATCH v15 QEMU 4/3 RFC] memory: Add support for MADV_FREE as mechanism to lazy discard pages Alexander Duyck
2019-12-12 23:47 ` [PATCH v15 0/7] mm / virtio: Provide support for free page reporting Alexander Duyck
2019-12-13 10:00 ` David Hildenbrand
2019-12-13 11:08 ` Mel Gorman
2019-12-13 16:59 ` Alexander Duyck
2019-12-13 16:46 ` Alexander Duyck
2019-12-16 12:21 ` David Hildenbrand
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=cb49bbc7-b0c0-65cc-1d9d-a3aaef075650@redhat.com \
--to=david@redhat.com \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=alexander.duyck@gmail.com \
--cc=alexander.h.duyck@linux.intel.com \
--cc=dan.j.williams@intel.com \
--cc=dave.hansen@intel.com \
--cc=konrad.wilk@oracle.com \
--cc=kvm@vger.kernel.org \
--cc=lcapitulino@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=mhocko@kernel.org \
--cc=mst@redhat.com \
--cc=nitesh@redhat.com \
--cc=osalvador@suse.de \
--cc=pagupta@redhat.com \
--cc=pbonzini@redhat.com \
--cc=riel@surriel.com \
--cc=vbabka@suse.cz \
--cc=wei.w.wang@intel.com \
--cc=willy@infradead.org \
--cc=yang.zhang.wz@gmail.com \
/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).