From: Arjun Roy <arjunroy@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjun Roy <arjunroy.kdev@gmail.com>,
davem@davemloft.net, netdev@vger.kernel.org, linux-mm@kvack.org,
Eric Dumazet <edumazet@google.com>,
Soheil Hassas Yeganeh <soheil@google.com>
Subject: Re: [PATCH resend mm,net-next 1/3] mm: Refactor insert_page to prepare for batched-lock insert.
Date: Thu, 13 Feb 2020 08:52:34 -0800 [thread overview]
Message-ID: <CAOFY-A0iq89D3Je8oSFkPAUnKYhqFia=4SC7-EkB0beOz2w5+w@mail.gmail.com> (raw)
In-Reply-To: <20200212184115.127c17c6b0f9dab6fcae56c2@linux-foundation.org>
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The addition of page_has_type() looks good to me, thanks!
-Arjun
On Wed, Feb 12, 2020 at 6:41 PM Andrew Morton <akpm@linux-foundation.org>
wrote:
> On Mon, 27 Jan 2020 18:59:56 -0800 Arjun Roy <arjunroy.kdev@gmail.com>
> wrote:
>
> > Add helper methods for vm_insert_page()/insert_page() to prepare for
> > vm_insert_pages(), which batch-inserts pages to reduce spinlock
> > operations when inserting multiple consecutive pages into the user
> > page table.
> >
> > The intention of this patch-set is to reduce atomic ops for
> > tcp zerocopy receives, which normally hits the same spinlock multiple
> > times consecutively.
>
> I tweaked this a bit for the addition of page_has_type() to
> insert_page(). Please check.
>
>
>
> From: Arjun Roy <arjunroy.kdev@gmail.com>
> Subject: mm: Refactor insert_page to prepare for batched-lock insert.
>
> From: Arjun Roy <arjunroy@google.com>
>
> Add helper methods for vm_insert_page()/insert_page() to prepare for
> vm_insert_pages(), which batch-inserts pages to reduce spinlock
> operations when inserting multiple consecutive pages into the user
> page table.
>
> The intention of this patch-set is to reduce atomic ops for
> tcp zerocopy receives, which normally hits the same spinlock multiple
> times consecutively.
>
> Link:
> http://lkml.kernel.org/r/20200128025958.43490-1-arjunroy.kdev@gmail.com
> Signed-off-by: Arjun Roy <arjunroy@google.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
> mm/memory.c | 39 ++++++++++++++++++++++++---------------
> 1 file changed, 24 insertions(+), 15 deletions(-)
>
> ---
> a/mm/memory.c~mm-refactor-insert_page-to-prepare-for-batched-lock-insert
> +++ a/mm/memory.c
> @@ -1430,6 +1430,27 @@ pte_t *__get_locked_pte(struct mm_struct
> return pte_alloc_map_lock(mm, pmd, addr, ptl);
> }
>
> +static int validate_page_before_insert(struct page *page)
> +{
> + if (PageAnon(page) || PageSlab(page) || page_has_type(page))
> + return -EINVAL;
> + flush_dcache_page(page);
> + return 0;
> +}
> +
> +static int insert_page_into_pte_locked(struct mm_struct *mm, pte_t *pte,
> + unsigned long addr, struct page *page, pgprot_t
> prot)
> +{
> + if (!pte_none(*pte))
> + return -EBUSY;
> + /* Ok, finally just insert the thing.. */
> + get_page(page);
> + inc_mm_counter_fast(mm, mm_counter_file(page));
> + page_add_file_rmap(page, false);
> + set_pte_at(mm, addr, pte, mk_pte(page, prot));
> + return 0;
> +}
> +
> /*
> * This is the old fallback for page remapping.
> *
> @@ -1445,26 +1466,14 @@ static int insert_page(struct vm_area_st
> pte_t *pte;
> spinlock_t *ptl;
>
> - retval = -EINVAL;
> - if (PageAnon(page) || PageSlab(page) || page_has_type(page))
> + retval = validate_page_before_insert(page);
> + if (retval)
> goto out;
> retval = -ENOMEM;
> - flush_dcache_page(page);
> pte = get_locked_pte(mm, addr, &ptl);
> if (!pte)
> goto out;
> - retval = -EBUSY;
> - if (!pte_none(*pte))
> - goto out_unlock;
> -
> - /* Ok, finally just insert the thing.. */
> - get_page(page);
> - inc_mm_counter_fast(mm, mm_counter_file(page));
> - page_add_file_rmap(page, false);
> - set_pte_at(mm, addr, pte, mk_pte(page, prot));
> -
> - retval = 0;
> -out_unlock:
> + retval = insert_page_into_pte_locked(mm, pte, addr, page, prot);
> pte_unmap_unlock(pte, ptl);
> out:
> return retval;
> _
>
>
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next prev parent reply other threads:[~2020-02-13 16:52 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 2:59 [PATCH resend mm,net-next 1/3] mm: Refactor insert_page to prepare for batched-lock insert Arjun Roy
2020-01-28 2:59 ` [PATCH resend mm,net-next 2/3] mm: Add vm_insert_pages() Arjun Roy
2020-02-13 2:41 ` Andrew Morton
2020-02-13 17:09 ` Arjun Roy
2020-02-13 21:37 ` Linus Torvalds
2020-02-13 21:54 ` Matthew Wilcox
2020-02-13 22:06 ` Arjun Roy
2020-01-28 2:59 ` [PATCH resend mm,net-next 3/3] net-zerocopy: Use vm_insert_pages() for tcp rcv zerocopy Arjun Roy
2020-02-13 2:56 ` Andrew Morton
2020-02-17 2:49 ` Arjun Roy
2020-02-21 21:21 ` Arjun Roy
2020-02-24 3:37 ` Andrew Morton
2020-02-24 16:19 ` Arjun Roy
2020-04-10 19:04 ` Andrew Morton
2020-04-10 19:13 ` Arjun Roy
2020-04-10 19:15 ` Arjun Roy
2020-02-13 2:41 ` [PATCH resend mm,net-next 1/3] mm: Refactor insert_page to prepare for batched-lock insert Andrew Morton
2020-02-13 16:52 ` Arjun Roy [this message]
2020-02-13 16:55 ` Arjun Roy
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