From: Ira Weiny <ira.weiny@intel.com>
To: Pingfan Liu <kernelfans@gmail.com>
Cc: Linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Mike Rapoport <rppt@linux.ibm.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
John Hubbard <jhubbard@nvidia.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Christoph Hellwig <hch@lst.de>,
Keith Busch <keith.busch@intel.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Linux-kernel@vger.kernel.org
Subject: Re: [PATCHv2] mm/gup: speed up check_and_migrate_cma_pages() on huge page
Date: Sun, 23 Jun 2019 21:43:06 -0700 [thread overview]
Message-ID: <20190624044305.GA30102@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <1561349561-8302-1-git-send-email-kernelfans@gmail.com>
On Mon, Jun 24, 2019 at 12:12:41PM +0800, Pingfan Liu wrote:
> Both hugetlb and thp locate on the same migration type of pageblock, since
> they are allocated from a free_list[]. Based on this fact, it is enough to
> check on a single subpage to decide the migration type of the whole huge
> page. By this way, it saves (2M/4K - 1) times loop for pmd_huge on x86,
> similar on other archs.
>
> Furthermore, when executing isolate_huge_page(), it avoid taking global
> hugetlb_lock many times, and meanless remove/add to the local link list
> cma_page_list.
>
> Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Ira Weiny <ira.weiny@intel.com>
> Cc: Mike Rapoport <rppt@linux.ibm.com>
> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Keith Busch <keith.busch@intel.com>
> Cc: Mike Kravetz <mike.kravetz@oracle.com>
> Cc: Linux-kernel@vger.kernel.org
> ---
> mm/gup.c | 19 ++++++++++++-------
> 1 file changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index ddde097..544f5de 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1342,19 +1342,22 @@ static long check_and_migrate_cma_pages(struct task_struct *tsk,
> LIST_HEAD(cma_page_list);
>
> check_again:
> - for (i = 0; i < nr_pages; i++) {
> + for (i = 0; i < nr_pages;) {
> +
> + struct page *head = compound_head(pages[i]);
> + long step = 1;
> +
> + if (PageCompound(head))
> + step = compound_order(head) - (pages[i] - head);
Sorry if I missed this last time. compound_order() is not correct here.
Ira
> /*
> * If we get a page from the CMA zone, since we are going to
> * be pinning these entries, we might as well move them out
> * of the CMA zone if possible.
> */
> - if (is_migrate_cma_page(pages[i])) {
> -
> - struct page *head = compound_head(pages[i]);
> -
> - if (PageHuge(head)) {
> + if (is_migrate_cma_page(head)) {
> + if (PageHuge(head))
> isolate_huge_page(head, &cma_page_list);
> - } else {
> + else {
> if (!PageLRU(head) && drain_allow) {
> lru_add_drain_all();
> drain_allow = false;
> @@ -1369,6 +1372,8 @@ static long check_and_migrate_cma_pages(struct task_struct *tsk,
> }
> }
> }
> +
> + i += step;
> }
>
> if (!list_empty(&cma_page_list)) {
> --
> 2.7.5
>
next prev parent reply other threads:[~2019-06-24 4:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-24 4:12 [PATCHv2] mm/gup: speed up check_and_migrate_cma_pages() on huge page Pingfan Liu
2019-06-24 4:43 ` Ira Weiny [this message]
2019-06-24 5:32 ` Pingfan Liu
2019-06-24 5:34 ` Pingfan Liu
2019-06-24 23:01 ` Ira Weiny
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