From: Peter Xu <peterx@redhat.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Martin Cracauer <cracauer@cons.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Johannes Weiner <hannes@cmpxchg.org>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
David Hildenbrand <david@redhat.com>,
Bobby Powers <bobbypowers@gmail.com>,
Maya Gokhale <gokhale2@llnl.gov>,
Jerome Glisse <jglisse@redhat.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Matthew Wilcox <willy@infradead.org>,
Marty McFadden <mcfadden8@llnl.gov>, Mel Gorman <mgorman@suse.de>,
peterx@redhat.com, Hugh Dickins <hughd@google.com>,
Brian Geffon <bgeffon@google.com>,
Denis Plotnikov <dplotnikov@virtuozzo.com>,
Pavel Emelyanov <xemul@virtuozzo.com>
Subject: [PATCH RESEND v6 01/16] mm/gup: Rename "nonblocking" to "locked" where proper
Date: Thu, 20 Feb 2020 10:53:38 -0500 [thread overview]
Message-ID: <20200220155353.8676-2-peterx@redhat.com> (raw)
In-Reply-To: <20200220155353.8676-1-peterx@redhat.com>
There's plenty of places around __get_user_pages() that has a parameter
"nonblocking" which does not really mean that "it won't block" (because
it can really block) but instead it shows whether the mmap_sem is
released by up_read() during the page fault handling mostly when
VM_FAULT_RETRY is returned.
We have the correct naming in e.g. get_user_pages_locked() or
get_user_pages_remote() as "locked", however there're still many places
that are using the "nonblocking" as name.
Renaming the places to "locked" where proper to better suite the
functionality of the variable. While at it, fixing up some of the
comments accordingly.
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
mm/gup.c | 44 +++++++++++++++++++++-----------------------
mm/hugetlb.c | 8 ++++----
2 files changed, 25 insertions(+), 27 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 1b521e0ac1de..1b4411bd0042 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -630,12 +630,12 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address,
}
/*
- * mmap_sem must be held on entry. If @nonblocking != NULL and
- * *@flags does not include FOLL_NOWAIT, the mmap_sem may be released.
- * If it is, *@nonblocking will be set to 0 and -EBUSY returned.
+ * mmap_sem must be held on entry. If @locked != NULL and *@flags
+ * does not include FOLL_NOWAIT, the mmap_sem may be released. If it
+ * is, *@locked will be set to 0 and -EBUSY returned.
*/
static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
- unsigned long address, unsigned int *flags, int *nonblocking)
+ unsigned long address, unsigned int *flags, int *locked)
{
unsigned int fault_flags = 0;
vm_fault_t ret;
@@ -647,7 +647,7 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
fault_flags |= FAULT_FLAG_WRITE;
if (*flags & FOLL_REMOTE)
fault_flags |= FAULT_FLAG_REMOTE;
- if (nonblocking)
+ if (locked)
fault_flags |= FAULT_FLAG_ALLOW_RETRY;
if (*flags & FOLL_NOWAIT)
fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT;
@@ -673,8 +673,8 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
}
if (ret & VM_FAULT_RETRY) {
- if (nonblocking && !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
- *nonblocking = 0;
+ if (locked && !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
+ *locked = 0;
return -EBUSY;
}
@@ -751,7 +751,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
* only intends to ensure the pages are faulted in.
* @vmas: array of pointers to vmas corresponding to each page.
* Or NULL if the caller does not require them.
- * @nonblocking: whether waiting for disk IO or mmap_sem contention
+ * @locked: whether we're still with the mmap_sem held
*
* Returns either number of pages pinned (which may be less than the
* number requested), or an error. Details about the return value:
@@ -786,13 +786,11 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
* appropriate) must be called after the page is finished with, and
* before put_page is called.
*
- * If @nonblocking != NULL, __get_user_pages will not wait for disk IO
- * or mmap_sem contention, and if waiting is needed to pin all pages,
- * *@nonblocking will be set to 0. Further, if @gup_flags does not
- * include FOLL_NOWAIT, the mmap_sem will be released via up_read() in
- * this case.
+ * If @locked != NULL, *@locked will be set to 0 when mmap_sem is
+ * released by an up_read(). That can happen if @gup_flags does not
+ * have FOLL_NOWAIT.
*
- * A caller using such a combination of @nonblocking and @gup_flags
+ * A caller using such a combination of @locked and @gup_flags
* must therefore hold the mmap_sem for reading only, and recognize
* when it's been released. Otherwise, it must be held for either
* reading or writing and will not be released.
@@ -804,7 +802,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas, int *nonblocking)
+ struct vm_area_struct **vmas, int *locked)
{
long ret = 0, i = 0;
struct vm_area_struct *vma = NULL;
@@ -850,7 +848,7 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
if (is_vm_hugetlb_page(vma)) {
i = follow_hugetlb_page(mm, vma, pages, vmas,
&start, &nr_pages, i,
- gup_flags, nonblocking);
+ gup_flags, locked);
continue;
}
}
@@ -868,7 +866,7 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
page = follow_page_mask(vma, start, foll_flags, &ctx);
if (!page) {
ret = faultin_page(tsk, vma, start, &foll_flags,
- nonblocking);
+ locked);
switch (ret) {
case 0:
goto retry;
@@ -1129,7 +1127,7 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
* @vma: target vma
* @start: start address
* @end: end address
- * @nonblocking:
+ * @locked: whether the mmap_sem is still held
*
* This takes care of mlocking the pages too if VM_LOCKED is set.
*
@@ -1137,14 +1135,14 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
*
* vma->vm_mm->mmap_sem must be held.
*
- * If @nonblocking is NULL, it may be held for read or write and will
+ * If @locked is NULL, it may be held for read or write and will
* be unperturbed.
*
- * If @nonblocking is non-NULL, it must held for read only and may be
- * released. If it's released, *@nonblocking will be set to 0.
+ * If @locked is non-NULL, it must held for read only and may be
+ * released. If it's released, *@locked will be set to 0.
*/
long populate_vma_page_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long end, int *nonblocking)
+ unsigned long start, unsigned long end, int *locked)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long nr_pages = (end - start) / PAGE_SIZE;
@@ -1179,7 +1177,7 @@ long populate_vma_page_range(struct vm_area_struct *vma,
* not result in a stack expansion that recurses back here.
*/
return __get_user_pages(current, mm, start, nr_pages, gup_flags,
- NULL, NULL, nonblocking);
+ NULL, NULL, locked);
}
/*
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index dd8737a94bec..c84f721db020 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4266,7 +4266,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct page **pages, struct vm_area_struct **vmas,
unsigned long *position, unsigned long *nr_pages,
- long i, unsigned int flags, int *nonblocking)
+ long i, unsigned int flags, int *locked)
{
unsigned long pfn_offset;
unsigned long vaddr = *position;
@@ -4337,7 +4337,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
spin_unlock(ptl);
if (flags & FOLL_WRITE)
fault_flags |= FAULT_FLAG_WRITE;
- if (nonblocking)
+ if (locked)
fault_flags |= FAULT_FLAG_ALLOW_RETRY;
if (flags & FOLL_NOWAIT)
fault_flags |= FAULT_FLAG_ALLOW_RETRY |
@@ -4354,9 +4354,9 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
break;
}
if (ret & VM_FAULT_RETRY) {
- if (nonblocking &&
+ if (locked &&
!(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
- *nonblocking = 0;
+ *locked = 0;
*nr_pages = 0;
/*
* VM_FAULT_RETRY must not return an
--
2.24.1
next prev parent reply other threads:[~2020-02-20 15:54 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 15:53 [PATCH RESEND v6 00/16] mm: Page fault enhancements Peter Xu
2020-02-20 15:53 ` Peter Xu [this message]
2020-02-20 15:53 ` [PATCH RESEND v6 02/16] mm/gup: Fix __get_user_pages() on fault retry of hugetlb Peter Xu
2020-03-02 19:02 ` David Hildenbrand
2020-03-02 20:07 ` Peter Xu
2020-03-02 20:22 ` David Hildenbrand
2020-02-20 15:53 ` [PATCH RESEND v6 03/16] mm: Introduce fault_signal_pending() Peter Xu
2020-03-02 19:04 ` David Hildenbrand
2020-02-20 15:53 ` [PATCH RESEND v6 04/16] x86/mm: Use helper fault_signal_pending() Peter Xu
2020-02-20 15:58 ` [PATCH RESEND v6 05/16] arc/mm: " Peter Xu
2020-02-20 15:59 ` [PATCH RESEND v6 06/16] arm64/mm: " Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 07/16] powerpc/mm: " Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 08/16] sh/mm: " Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 09/16] mm: Return faster for non-fatal signals in user mode faults Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 10/16] userfaultfd: Don't retake mmap_sem to emulate NOPAGE Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 11/16] mm: Introduce FAULT_FLAG_DEFAULT Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 13/16] mm: Allow VM_FAULT_RETRY for multiple times Peter Xu
2020-02-20 16:02 ` [PATCH RESEND v6 15/16] mm/gup: Allow to react to fatal signals Peter Xu
2020-02-20 16:03 ` [PATCH RESEND v6 16/16] mm/userfaultfd: Honor FAULT_FLAG_KILLABLE in fault path Peter Xu
2020-02-20 19:53 ` [PATCH RESEND v6 12/16] mm: Introduce FAULT_FLAG_INTERRUPTIBLE Peter Xu
2020-02-20 19:53 ` [PATCH RESEND v6 14/16] mm/gup: Allow VM_FAULT_RETRY for multiple times Peter Xu
2020-02-21 19:26 ` [PATCH RESEND v6 00/16] mm: Page fault enhancements Brian Geffon
2020-03-02 17:31 ` Peter Xu
2020-02-21 19:32 ` Linus Torvalds
2020-02-21 20:11 ` Peter Xu
2020-03-07 20:33 ` David Hildenbrand
2020-03-07 21:47 ` Peter Xu
2020-03-08 12:12 ` David Hildenbrand
2020-03-09 19:51 ` Peter Xu
2020-03-09 20:06 ` David Hildenbrand
2020-03-08 12:49 ` David Hildenbrand
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=20200220155353.8676-2-peterx@redhat.com \
--to=peterx@redhat.com \
--cc=aarcange@redhat.com \
--cc=bgeffon@google.com \
--cc=bobbypowers@gmail.com \
--cc=cracauer@cons.org \
--cc=david@redhat.com \
--cc=dgilbert@redhat.com \
--cc=dplotnikov@virtuozzo.com \
--cc=gokhale2@llnl.gov \
--cc=hannes@cmpxchg.org \
--cc=hughd@google.com \
--cc=jglisse@redhat.com \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mcfadden8@llnl.gov \
--cc=mgorman@suse.de \
--cc=mike.kravetz@oracle.com \
--cc=rppt@linux.vnet.ibm.com \
--cc=torvalds@linux-foundation.org \
--cc=willy@infradead.org \
--cc=xemul@virtuozzo.com \
/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).