The patch titled
Subject: userfaultfd: non-cooperative: add madvise() event for MADV_DONTNEED request
has been added to the -mm tree. Its filename is
userfaultfd-non-cooperative-add-madvise-event-for-madv_dontneed-request.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-non-cooperative-add-madvise-event-for-madv_dontneed-request.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-non-cooperative-add-madvise-event-for-madv_dontneed-request.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Subject: userfaultfd: non-cooperative: add madvise() event for MADV_DONTNEED request
If the page is punched out of the address space the uffd reader should
know this and zeromap the respective area in case of the #PF event.
Link: http://lkml.kernel.org/r/20161216144821.5183-14-aarcange@xxxxxxxxxx
Signed-off-by: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: "Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Cc: Michael Rapoport <RAPOPORT@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/userfaultfd.c | 28 ++++++++++++++++++++++++++++
include/linux/userfaultfd_k.h | 12 ++++++++++++
include/uapi/linux/userfaultfd.h | 10 +++++++++-
mm/madvise.c | 2 ++
4 files changed, 51 insertions(+), 1 deletion(-)
diff -puN fs/userfaultfd.c~userfaultfd-non-cooperative-add-madvise-event-for-madv_dontneed-request fs/userfaultfd.c
--- a/fs/userfaultfd.c~userfaultfd-non-cooperative-add-madvise-event-for-madv_dontneed-request
+++ a/fs/userfaultfd.c
@@ -600,6 +600,34 @@ void mremap_userfaultfd_complete(struct
userfaultfd_event_wait_completion(ctx, &ewq);
}
+void madvise_userfault_dontneed(struct vm_area_struct *vma,
+ struct vm_area_struct **prev,
+ unsigned long start, unsigned long end)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ struct userfaultfd_ctx *ctx;
+ struct userfaultfd_wait_queue ewq;
+
+ ctx = vma->vm_userfaultfd_ctx.ctx;
+ if (!ctx || !(ctx->features & UFFD_FEATURE_EVENT_MADVDONTNEED))
+ return;
+
+ userfaultfd_ctx_get(ctx);
+ up_read(&mm->mmap_sem);
+
+ *prev = NULL; /* We wait for ACK w/o the mmap semaphore */
+
+ msg_init(&ewq.msg);
+
+ ewq.msg.event = UFFD_EVENT_MADVDONTNEED;
+ ewq.msg.arg.madv_dn.start = start;
+ ewq.msg.arg.madv_dn.end = end;
+
+ userfaultfd_event_wait_completion(ctx, &ewq);
+
+ down_read(&mm->mmap_sem);
+}
+
static int userfaultfd_release(struct inode *inode, struct file *file)
{
struct userfaultfd_ctx *ctx = file->private_data;
diff -puN include/linux/userfaultfd_k.h~userfaultfd-non-cooperative-add-madvise-event-for-madv_dontneed-request include/linux/userfaultfd_k.h
--- a/include/linux/userfaultfd_k.h~userfaultfd-non-cooperative-add-madvise-event-for-madv_dontneed-request
+++ a/include/linux/userfaultfd_k.h
@@ -61,6 +61,11 @@ extern void mremap_userfaultfd_complete(
unsigned long from, unsigned long to,
unsigned long len);
+extern void madvise_userfault_dontneed(struct vm_area_struct *vma,
+ struct vm_area_struct **prev,
+ unsigned long start,
+ unsigned long end);
+
#else /* CONFIG_USERFAULTFD */
/* mm helpers */
@@ -106,6 +111,13 @@ static inline void mremap_userfaultfd_co
unsigned long len)
{
}
+
+static inline void madvise_userfault_dontneed(struct vm_area_struct *vma,
+ struct vm_area_struct **prev,
+ unsigned long start,
+ unsigned long end)
+{
+}
#endif /* CONFIG_USERFAULTFD */
#endif /* _LINUX_USERFAULTFD_K_H */
diff -puN include/uapi/linux/userfaultfd.h~userfaultfd-non-cooperative-add-madvise-event-for-madv_dontneed-request include/uapi/linux/userfaultfd.h
--- a/include/uapi/linux/userfaultfd.h~userfaultfd-non-cooperative-add-madvise-event-for-madv_dontneed-request
+++ a/include/uapi/linux/userfaultfd.h
@@ -19,7 +19,8 @@
*/
#define UFFD_API ((__u64)0xAA)
#define UFFD_API_FEATURES (UFFD_FEATURE_EVENT_FORK | \
- UFFD_FEATURE_EVENT_REMAP)
+ UFFD_FEATURE_EVENT_REMAP | \
+ UFFD_FEATURE_EVENT_MADVDONTNEED)
#define UFFD_API_IOCTLS \
((__u64)1 << _UFFDIO_REGISTER | \
(__u64)1 << _UFFDIO_UNREGISTER | \
@@ -84,6 +85,11 @@ struct uffd_msg {
} remap;
struct {
+ __u64 start;
+ __u64 end;
+ } madv_dn;
+
+ struct {
/* unused reserved fields */
__u64 reserved1;
__u64 reserved2;
@@ -98,6 +104,7 @@ struct uffd_msg {
#define UFFD_EVENT_PAGEFAULT 0x12
#define UFFD_EVENT_FORK 0x13
#define UFFD_EVENT_REMAP 0x14
+#define UFFD_EVENT_MADVDONTNEED 0x15
/* flags for UFFD_EVENT_PAGEFAULT */
#define UFFD_PAGEFAULT_FLAG_WRITE (1<<0) /* If this was a write fault */
@@ -119,6 +126,7 @@ struct uffdio_api {
#define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0)
#define UFFD_FEATURE_EVENT_FORK (1<<1)
#define UFFD_FEATURE_EVENT_REMAP (1<<2)
+#define UFFD_FEATURE_EVENT_MADVDONTNEED (1<<3)
__u64 features;
__u64 ioctls;
diff -puN mm/madvise.c~userfaultfd-non-cooperative-add-madvise-event-for-madv_dontneed-request mm/madvise.c
--- a/mm/madvise.c~userfaultfd-non-cooperative-add-madvise-event-for-madv_dontneed-request
+++ a/mm/madvise.c
@@ -10,6 +10,7 @@
#include <linux/syscalls.h>
#include <linux/mempolicy.h>
#include <linux/page-isolation.h>
+#include <linux/userfaultfd_k.h>
#include <linux/hugetlb.h>
#include <linux/falloc.h>
#include <linux/sched.h>
@@ -477,6 +478,7 @@ static long madvise_dontneed(struct vm_a
return -EINVAL;
zap_page_range(vma, start, end - start, NULL);
+ madvise_userfault_dontneed(vma, prev, start, end);
return 0;
}
_
Patches currently in -mm which might be from xemul@xxxxxxxxxxxxx are
userfaultfd-non-cooperative-split-the-find_userfault-routine.patch
userfaultfd-non-cooperative-add-ability-to-report-non-pf-events-from-uffd-descriptor.patch
userfaultfd-non-cooperative-add-fork-event.patch
userfaultfd-non-cooperative-add-mremap-event.patch
userfaultfd-non-cooperative-add-madvise-event-for-madv_dontneed-request.patch
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