From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Matthew Wilcox <willy@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>,
linux-mm@kvack.org, linux-nvdimm@ml01.01.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
x86@kernel.org
Subject: Re: [PATCH 1/8] mm: Add optional support for PUD-sized transparent hugepages
Date: Mon, 4 Jan 2016 22:30:42 +0200 [thread overview]
Message-ID: <20160104203041.GB13515@node.shutemov.name> (raw)
In-Reply-To: <20160102170638.GL2457@linux.intel.com>
On Sat, Jan 02, 2016 at 12:06:38PM -0500, Matthew Wilcox wrote:
> On Mon, Dec 28, 2015 at 12:05:51PM +0200, Kirill A. Shutemov wrote:
> > On Thu, Dec 24, 2015 at 11:20:30AM -0500, Matthew Wilcox wrote:
> > > diff --git a/include/linux/mm.h b/include/linux/mm.h
> > > index 4bf3811..e14634f 100644
> > > --- a/include/linux/mm.h
> > > +++ b/include/linux/mm.h
> > > @@ -1958,6 +1977,17 @@ static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd)
> > > return ptl;
> > > }
> > >
> > > +/*
> > > + * No scalability reason to split PUD locks yet, but follow the same pattern
> > > + * as the PMD locks to make it easier if we have to.
> > > + */
> >
> > I don't think it makes any good unless you convert all other places where
> > we use page_table_lock to protect pud table (like __pud_alloc()) to the
> > same API.
> > I think this would deserve separate patch.
>
> Sure, a separate patch to convert existing users of the PTL. But I
> don't think it does any harm to introduce the PUD version of the PMD API.
> Maybe with a comment indicating that tere is significant work to be done
> in converting existing users to this API?
I think that's fine with the fat comment around pud_lock() definition.
> > > diff --git a/mm/memory.c b/mm/memory.c
> > > index 416b129..7328df0 100644
> > > --- a/mm/memory.c
> > > +++ b/mm/memory.c
> > > @@ -1220,9 +1220,27 @@ static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
> > > pud = pud_offset(pgd, addr);
> > > do {
> > > next = pud_addr_end(addr, end);
> > > + if (pud_trans_huge(*pud) || pud_devmap(*pud)) {
> > > + if (next - addr != HPAGE_PUD_SIZE) {
> > > +#ifdef CONFIG_DEBUG_VM
> >
> > IS_ENABLED(CONFIG_DEBUG_VM) ?
> >
> > > + if (!rwsem_is_locked(&tlb->mm->mmap_sem)) {
> > > + pr_err("%s: mmap_sem is unlocked! addr=0x%lx end=0x%lx vma->vm_start=0x%lx vma->vm_end=0x%lx\n",
> > > + __func__, addr, end,
> > > + vma->vm_start,
> > > + vma->vm_end);
> >
> > dump_vma(), I guess.
>
> These two issues are copy-and-paste from the existing PMD code. I'm happy
> to update the PMD code to the new-and-improved way of doing things;
> I'm just not keen to have the PMD and PUD code diverge unnecessarily.
Yes, please update PMD too. It looks ugly. VM_BUG_ON_VMA() is probably
right way to deal with this.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2016-01-04 20:30 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-24 16:20 [PATCH 0/8] Support for transparent PUD pages Matthew Wilcox
2015-12-24 16:20 ` [PATCH 1/8] mm: Add optional support for PUD-sized transparent hugepages Matthew Wilcox
2015-12-28 10:05 ` Kirill A. Shutemov
2016-01-02 17:06 ` Matthew Wilcox
2016-01-04 20:30 ` Kirill A. Shutemov [this message]
2015-12-28 10:11 ` Kirill A. Shutemov
2015-12-24 16:20 ` [PATCH 2/8] mincore: Add support for PUDs Matthew Wilcox
2015-12-24 16:20 ` [PATCH 3/8] procfs: Add support for PUDs to smaps, clear_refs and pagemap Matthew Wilcox
2015-12-24 16:20 ` [PATCH 4/8] x86: Add support for PUD-sized transparent hugepages Matthew Wilcox
2015-12-24 16:20 ` [PATCH 5/8] dax: Support for transparent PUD pages Matthew Wilcox
2015-12-24 16:20 ` [PATCH 6/8] block_dev: Support PUD DAX mappings Matthew Wilcox
2015-12-24 16:20 ` [PATCH 7/8] xfs: Support for transparent PUD pages Matthew Wilcox
2015-12-30 23:30 ` Dave Chinner
2016-01-02 16:43 ` Matthew Wilcox
2016-01-03 20:33 ` Dave Chinner
2016-01-04 20:41 ` Kirill A. Shutemov
2016-01-04 22:01 ` Matthew Wilcox
2015-12-24 16:20 ` [PATCH 8/8] ext4: Transparent support for PUD-sized transparent huge pages Matthew Wilcox
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=20160104203041.GB13515@node.shutemov.name \
--to=kirill@shutemov.name \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-nvdimm@ml01.01.org \
--cc=matthew.r.wilcox@intel.com \
--cc=willy@linux.intel.com \
--cc=x86@kernel.org \
/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).