The addition of page_has_type() looks good to me, thanks! -Arjun On Wed, Feb 12, 2020 at 6:41 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Mon, 27 Jan 2020 18:59:56 -0800 Arjun Roy <arjunroy.kdev@xxxxxxxxx> 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@xxxxxxxxx> > Subject: mm: Refactor insert_page to prepare for batched-lock insert. > > From: Arjun Roy <arjunroy@xxxxxxxxxx> > > 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@xxxxxxxxx > Signed-off-by: Arjun Roy <arjunroy@xxxxxxxxxx> > Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> > Signed-off-by: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx> > > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > --- > > 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; > _ >
