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From: John Hubbard <jhubbard@nvidia.com>
To: Joao Martins <joao.m.martins@oracle.com>, <linux-mm@kvack.org>
Cc: linux-nvdimm@lists.01.org, Matthew Wilcox <willy@infradead.org>,
	"Jason Gunthorpe  <jgg@ziepe.ca>, Jane Chu <jane.chu@oracle.com>,
	Muchun Song" <songmuchun@bytedance.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Andrew@ml01.01.org
Subject: Re: [PATCH RFC 8/9] RDMA/umem: batch page unpin in __ib_mem_release()
Date: Tue, 8 Dec 2020 21:18:57 -0800	[thread overview]
Message-ID: <68d7bedf-99b4-6c7f-02f6-3188474b366c@nvidia.com> (raw)
In-Reply-To: <20201208172901.17384-10-joao.m.martins@oracle.com>

On 12/8/20 9:29 AM, Joao Martins wrote:
> Take advantage of the newly added unpin_user_pages() batched
> refcount update, by calculating a page array from an SGL
> (same size as the one used in ib_mem_get()) and call
> unpin_user_pages() with that.
> 
> unpin_user_pages() will check on consecutive pages that belong
> to the same compound page set and batch the refcount update in
> a single write.
> 
> Running a test program which calls mr reg/unreg on a 1G in size
> and measures cost of both operations together (in a guest using rxe)
> with device-dax and hugetlbfs:
> 
> Before:
> 159 rounds in 5.027 sec: 31617.923 usec / round (device-dax)
> 466 rounds in 5.009 sec: 10748.456 usec / round (hugetlbfs)
> 
> After:
>   305 rounds in 5.010 sec: 16426.047 usec / round (device-dax)
> 1073 rounds in 5.004 sec: 4663.622 usec / round (hugetlbfs)
> 
> We also see similar improvements on a setup with pmem and RDMA hardware.
> 
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>   drivers/infiniband/core/umem.c | 25 ++++++++++++++++++++++---
>   1 file changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
> index e9fecbdf391b..493cfdcf7381 100644
> --- a/drivers/infiniband/core/umem.c
> +++ b/drivers/infiniband/core/umem.c
> @@ -44,20 +44,40 @@
>   
>   #include "uverbs.h"
>   
> +#define PAGES_PER_LIST (PAGE_SIZE / sizeof(struct page *))

I was going to maybe suggest that this item, and the "bool make_dirty" cleanup,
be a separate patch, because they are just cleanups. But the memory allocation issue
below might make that whole (minor) point obsolete.

> +
>   static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
>   {
> +	bool make_dirty = umem->writable && dirty;
> +	struct page **page_list = NULL;
>   	struct sg_page_iter sg_iter;
> +	unsigned long nr = 0;
>   	struct page *page;
>   
> +	page_list = (struct page **) __get_free_page(GFP_KERNEL);

Yeah, allocating memory in a free/release path is not good. btw, for future use,
I see that kmalloc() is generally recommended these days (that's a change), when
you want a pointer to storage, as opposed to wanting struct pages:

https://lore.kernel.org/lkml/CA+55aFwyxJ+TOpaJZnC5MPJ-25xbLAEu8iJP8zTYhmA3LXFF8Q@mail.gmail.com/

> +
>   	if (umem->nmap > 0)
>   		ib_dma_unmap_sg(dev, umem->sg_head.sgl, umem->sg_nents,
>   				DMA_BIDIRECTIONAL);
>   
>   	for_each_sg_page(umem->sg_head.sgl, &sg_iter, umem->sg_nents, 0) {
>   		page = sg_page_iter_page(&sg_iter);
> -		unpin_user_pages_dirty_lock(&page, 1, umem->writable && dirty);
> +		if (page_list)
> +			page_list[nr++] = page;
> +
> +		if (!page_list) {
> +			unpin_user_pages_dirty_lock(&page, 1, make_dirty);
> +		} else if (nr == PAGES_PER_LIST) {
> +			unpin_user_pages_dirty_lock(page_list, nr, make_dirty);
> +			nr = 0;
> +		}
>   	}
>   
> +	if (nr)
> +		unpin_user_pages_dirty_lock(page_list, nr, make_dirty);
> +
> +	if (page_list)
> +		free_page((unsigned long) page_list);
>   	sg_free_table(&umem->sg_head);
>   }
>   
> @@ -212,8 +232,7 @@ struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
>   		cond_resched();
>   		ret = pin_user_pages_fast(cur_base,
>   					  min_t(unsigned long, npages,
> -						PAGE_SIZE /
> -						sizeof(struct page *)),
> +						PAGES_PER_LIST),
>   					  gup_flags | FOLL_LONGTERM, page_list);
>   		if (ret < 0)
>   			goto umem_release;
> 

thanks,
-- 
John Hubbard
NVIDIA
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org

WARNING: multiple messages have this Message-ID
From: John Hubbard <jhubbard@nvidia.com>
To: Joao Martins <joao.m.martins@oracle.com>, <linux-mm@kvack.org>
Cc: Dan Williams <dan.j.williams@intel.com>,
	Ira Weiny <ira.weiny@intel.com>, <linux-nvdimm@lists.01.org>,
	Matthew Wilcox <willy@infradead.org>,
	"Jason Gunthorpe" <jgg@ziepe.ca>, Jane Chu <jane.chu@oracle.com>,
	Muchun Song <songmuchun@bytedance.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	"Andrew Morton" <akpm@linux-foundation.org>
Subject: Re: [PATCH RFC 8/9] RDMA/umem: batch page unpin in __ib_mem_release()
Date: Tue, 8 Dec 2020 21:18:57 -0800	[thread overview]
Message-ID: <68d7bedf-99b4-6c7f-02f6-3188474b366c@nvidia.com> (raw)
In-Reply-To: <20201208172901.17384-10-joao.m.martins@oracle.com>

On 12/8/20 9:29 AM, Joao Martins wrote:
> Take advantage of the newly added unpin_user_pages() batched
> refcount update, by calculating a page array from an SGL
> (same size as the one used in ib_mem_get()) and call
> unpin_user_pages() with that.
> 
> unpin_user_pages() will check on consecutive pages that belong
> to the same compound page set and batch the refcount update in
> a single write.
> 
> Running a test program which calls mr reg/unreg on a 1G in size
> and measures cost of both operations together (in a guest using rxe)
> with device-dax and hugetlbfs:
> 
> Before:
> 159 rounds in 5.027 sec: 31617.923 usec / round (device-dax)
> 466 rounds in 5.009 sec: 10748.456 usec / round (hugetlbfs)
> 
> After:
>   305 rounds in 5.010 sec: 16426.047 usec / round (device-dax)
> 1073 rounds in 5.004 sec: 4663.622 usec / round (hugetlbfs)
> 
> We also see similar improvements on a setup with pmem and RDMA hardware.
> 
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>   drivers/infiniband/core/umem.c | 25 ++++++++++++++++++++++---
>   1 file changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
> index e9fecbdf391b..493cfdcf7381 100644
> --- a/drivers/infiniband/core/umem.c
> +++ b/drivers/infiniband/core/umem.c
> @@ -44,20 +44,40 @@
>   
>   #include "uverbs.h"
>   
> +#define PAGES_PER_LIST (PAGE_SIZE / sizeof(struct page *))

I was going to maybe suggest that this item, and the "bool make_dirty" cleanup,
be a separate patch, because they are just cleanups. But the memory allocation issue
below might make that whole (minor) point obsolete.

> +
>   static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
>   {
> +	bool make_dirty = umem->writable && dirty;
> +	struct page **page_list = NULL;
>   	struct sg_page_iter sg_iter;
> +	unsigned long nr = 0;
>   	struct page *page;
>   
> +	page_list = (struct page **) __get_free_page(GFP_KERNEL);

Yeah, allocating memory in a free/release path is not good. btw, for future use,
I see that kmalloc() is generally recommended these days (that's a change), when
you want a pointer to storage, as opposed to wanting struct pages:

https://lore.kernel.org/lkml/CA+55aFwyxJ+TOpaJZnC5MPJ-25xbLAEu8iJP8zTYhmA3LXFF8Q@mail.gmail.com/

> +
>   	if (umem->nmap > 0)
>   		ib_dma_unmap_sg(dev, umem->sg_head.sgl, umem->sg_nents,
>   				DMA_BIDIRECTIONAL);
>   
>   	for_each_sg_page(umem->sg_head.sgl, &sg_iter, umem->sg_nents, 0) {
>   		page = sg_page_iter_page(&sg_iter);
> -		unpin_user_pages_dirty_lock(&page, 1, umem->writable && dirty);
> +		if (page_list)
> +			page_list[nr++] = page;
> +
> +		if (!page_list) {
> +			unpin_user_pages_dirty_lock(&page, 1, make_dirty);
> +		} else if (nr == PAGES_PER_LIST) {
> +			unpin_user_pages_dirty_lock(page_list, nr, make_dirty);
> +			nr = 0;
> +		}
>   	}
>   
> +	if (nr)
> +		unpin_user_pages_dirty_lock(page_list, nr, make_dirty);
> +
> +	if (page_list)
> +		free_page((unsigned long) page_list);
>   	sg_free_table(&umem->sg_head);
>   }
>   
> @@ -212,8 +232,7 @@ struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
>   		cond_resched();
>   		ret = pin_user_pages_fast(cur_base,
>   					  min_t(unsigned long, npages,
> -						PAGE_SIZE /
> -						sizeof(struct page *)),
> +						PAGES_PER_LIST),
>   					  gup_flags | FOLL_LONGTERM, page_list);
>   		if (ret < 0)
>   			goto umem_release;
> 

thanks,
-- 
John Hubbard
NVIDIA


  parent reply	other threads:[~2020-12-09  5:19 UTC|newest]

Thread overview: 147+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-08 17:28 [PATCH RFC 0/9] mm, sparse-vmemmap: Introduce compound pagemaps Joao Martins
2020-12-08 17:28 ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 1/9] memremap: add ZONE_DEVICE support for compound pages Joao Martins
2020-12-08 17:28   ` Joao Martins
2020-12-09  5:59   ` John Hubbard
2020-12-09  5:59     ` John Hubbard
2020-12-09  6:33     ` Matthew Wilcox
2020-12-09  6:33       ` Matthew Wilcox
2020-12-09 13:12       ` Joao Martins
2020-12-09 13:12         ` Joao Martins
2021-02-20  1:43     ` Dan Williams
2021-02-20  1:43       ` Dan Williams
2021-02-22 11:24       ` Joao Martins
2021-02-22 11:24         ` Joao Martins
2021-02-22 20:37         ` Dan Williams
2021-02-22 20:37           ` Dan Williams
2021-02-23 15:46           ` Joao Martins
2021-02-23 15:46             ` Joao Martins
2021-02-23 16:50             ` Dan Williams
2021-02-23 16:50               ` Dan Williams
2021-02-23 17:18               ` Joao Martins
2021-02-23 17:18                 ` Joao Martins
2021-02-23 18:18                 ` Dan Williams
2021-02-23 18:18                   ` Dan Williams
2021-03-10 18:12           ` Joao Martins
2021-03-10 18:12             ` Joao Martins
2021-03-12  5:54             ` Dan Williams
2021-03-12  5:54               ` Dan Williams
2021-02-20  1:24   ` Dan Williams
2021-02-20  1:24     ` Dan Williams
2021-02-22 11:09     ` Joao Martins
2021-02-22 11:09       ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 2/9] sparse-vmemmap: Consolidate arguments in vmemmap section populate Joao Martins
2020-12-08 17:28   ` Joao Martins
2020-12-09  6:16   ` John Hubbard
2020-12-09  6:16     ` John Hubbard
2020-12-09 13:51     ` Joao Martins
2020-12-09 13:51       ` Joao Martins
2021-02-20  1:49   ` Dan Williams
2021-02-20  1:49     ` Dan Williams
2021-02-22 11:26     ` Joao Martins
2021-02-22 11:26       ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 3/9] sparse-vmemmap: Reuse vmemmap areas for a given mhp_params::align Joao Martins
2020-12-08 17:28   ` Joao Martins
2020-12-08 17:38   ` Joao Martins
2020-12-08 17:38     ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 3/9] sparse-vmemmap: Reuse vmemmap areas for a given page size Joao Martins
2020-12-08 17:28   ` Joao Martins
2021-02-20  3:34   ` Dan Williams
2021-02-20  3:34     ` Dan Williams
2021-02-22 11:42     ` Joao Martins
2021-02-22 11:42       ` Joao Martins
2021-02-22 22:40       ` Dan Williams
2021-02-22 22:40         ` Dan Williams
2021-02-23 15:46         ` Joao Martins
2021-02-23 15:46           ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 4/9] mm/page_alloc: Reuse tail struct pages for compound pagemaps Joao Martins
2020-12-08 17:28   ` Joao Martins
2021-02-20  6:17   ` Dan Williams
2021-02-20  6:17     ` Dan Williams
2021-02-22 12:01     ` Joao Martins
2021-02-22 12:01       ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 5/9] device-dax: Compound pagemap support Joao Martins
2020-12-08 17:28   ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 6/9] mm/gup: Grab head page refcount once for group of subpages Joao Martins
2020-12-08 17:28   ` Joao Martins
2020-12-08 19:49   ` Jason Gunthorpe
2020-12-09 11:05     ` Joao Martins
2020-12-09 11:05       ` Joao Martins
2020-12-09 15:15       ` Jason Gunthorpe
2020-12-09 16:02         ` Joao Martins
2020-12-09 16:02           ` Joao Martins
2020-12-09 16:24           ` Jason Gunthorpe
2020-12-09 17:27             ` Joao Martins
2020-12-09 17:27               ` Joao Martins
2020-12-09 18:14             ` Matthew Wilcox
2020-12-09 18:14               ` Matthew Wilcox
2020-12-09 19:08               ` Jason Gunthorpe
2020-12-10 15:43               ` Joao Martins
2020-12-10 15:43                 ` Joao Martins
2020-12-09  4:40   ` John Hubbard
2020-12-09  4:40     ` John Hubbard
2020-12-09 13:44     ` Joao Martins
2020-12-09 13:44       ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 7/9] mm/gup: Decrement head page " Joao Martins
2020-12-08 17:28   ` Joao Martins
2020-12-08 19:34   ` Jason Gunthorpe
2020-12-09  5:06     ` John Hubbard
2020-12-09  5:06       ` John Hubbard
2020-12-09 13:43       ` Jason Gunthorpe
2020-12-09 12:17     ` Joao Martins
2020-12-09 12:17       ` Joao Martins
2020-12-17 19:05     ` Joao Martins
2020-12-17 19:05       ` Joao Martins
2020-12-17 20:05       ` Jason Gunthorpe
2020-12-17 22:34         ` Joao Martins
2020-12-17 22:34           ` Joao Martins
2020-12-18 14:25           ` Jason Gunthorpe
2020-12-19  2:06         ` John Hubbard
2020-12-19  2:06           ` John Hubbard
2020-12-19 13:10           ` Joao Martins
2020-12-19 13:10             ` Joao Martins
2020-12-08 17:29 ` [PATCH RFC 8/9] RDMA/umem: batch page unpin in __ib_mem_release() Joao Martins
2020-12-08 17:29   ` Joao Martins
2020-12-08 19:29   ` Jason Gunthorpe
2020-12-09 10:59     ` Joao Martins
2020-12-09 10:59       ` Joao Martins
2020-12-19 13:15       ` Joao Martins
2020-12-19 13:15         ` Joao Martins
2020-12-09  5:18   ` John Hubbard [this message]
2020-12-09  5:18     ` John Hubbard
2020-12-08 17:29 ` [PATCH RFC 9/9] mm: Add follow_devmap_page() for devdax vmas Joao Martins
2020-12-08 17:29   ` Joao Martins
2020-12-08 19:57   ` Jason Gunthorpe
2020-12-09  8:05     ` Christoph Hellwig
2020-12-09  8:05       ` Christoph Hellwig
2020-12-09 11:19     ` Joao Martins
2020-12-09 11:19       ` Joao Martins
2020-12-09  5:23   ` John Hubbard
2020-12-09  5:23     ` John Hubbard
2020-12-09  9:38 ` [PATCH RFC 0/9] mm, sparse-vmemmap: Introduce compound pagemaps David Hildenbrand
2020-12-09  9:38   ` David Hildenbrand
2020-12-09  9:52 ` [External] " Muchun Song
2020-12-09  9:52   ` Muchun Song
2021-02-20  1:18 ` Dan Williams
2021-02-20  1:18   ` Dan Williams
2021-02-22 11:06   ` Joao Martins
2021-02-22 11:06     ` Joao Martins
2021-02-22 14:32     ` Joao Martins
2021-02-22 14:32       ` Joao Martins
2021-02-23 16:28   ` Joao Martins
2021-02-23 16:28     ` Joao Martins
2021-02-23 16:44     ` Dan Williams
2021-02-23 16:44       ` Dan Williams
2021-02-23 17:15       ` Joao Martins
2021-02-23 17:15         ` Joao Martins
2021-02-23 18:15         ` Dan Williams
2021-02-23 18:15           ` Dan Williams
2021-02-23 18:54       ` Jason Gunthorpe
2021-02-23 22:48         ` Dan Williams
2021-02-23 22:48           ` Dan Williams
2021-02-23 23:07           ` Jason Gunthorpe
2021-02-24  0:14             ` Dan Williams
2021-02-24  0:14               ` Dan Williams
2021-02-24  1:00               ` Jason Gunthorpe
2021-02-24  1:32                 ` Dan Williams
2021-02-24  1:32                   ` Dan Williams

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