This is the first advice that makes use of process_madvise() flags.
Add the necessary plumbing to make the flags available from do_madvise()
handlers.
For MADV_COLLAPSE, the added flags are:
* MADV_F_COLLAPSE_LIMITS - controls if we should respect
khugepaged/max_ptes_* limits
(requires CAP_SYS_ADMIN if not acting on
self)
* MADV_F_COLLAPSE_DEFRAG - force enable defrag, despite vma or system
settings.
These two flags together provide userspace flexibility in defining
separate policies for synchronous userspace-directed collapse, and
asynchronous kernel (khugepaged) collapse.
Signed-off-by: Zach O'Keefe <zokeefe@xxxxxxxxxx>
---
fs/io_uring.c | 3 +-
include/linux/huge_mm.h | 3 +-
include/linux/mm.h | 3 +-
include/uapi/asm-generic/mman-common.h | 8 +++++
mm/khugepaged.c | 7 +++--
mm/madvise.c | 42 ++++++++++++++------------
6 files changed, 41 insertions(+), 25 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 23e7f93d3956..8558b7549431 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4720,7 +4720,8 @@ static int io_madvise(struct io_kiocb *req, unsigned int issue_flags)
if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
- ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice);
+ ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice,
+ MADV_F_NONE);
if (ret < 0)
req_set_fail(req);
io_req_complete(req, ret);
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 407b63ab4185..31f514ff36be 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -228,7 +228,8 @@ int hugepage_madvise(struct vm_area_struct *vma, unsigned long *vm_flags,
int advice);
int madvise_collapse(struct vm_area_struct *vma,
struct vm_area_struct **prev,
- unsigned long start, unsigned long end);
+ unsigned long start, unsigned long end,
+ unsigned int flags);
void vma_adjust_trans_huge(struct vm_area_struct *vma, unsigned long start,
unsigned long end, long adjust_next);
spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index dc69d2a69912..f4776f4cda48 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2690,7 +2690,8 @@ extern int __do_munmap(struct mm_struct *, unsigned long, size_t,
struct list_head *uf, bool downgrade);
extern int do_munmap(struct mm_struct *, unsigned long, size_t,
struct list_head *uf);
-extern int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior);
+extern int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in,
+ int behavior, unsigned int flags);
#ifdef CONFIG_MMU
extern int __mm_populate(unsigned long addr, unsigned long len,
diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
index 6ce1f1ceb432..b81f4b1b18ba 100644
--- a/include/uapi/asm-generic/mman-common.h
+++ b/include/uapi/asm-generic/mman-common.h
@@ -79,6 +79,14 @@
#define MADV_COLLAPSE 25 /* Synchronous hugepage collapse */
+/* process_madvise() flags */
+#define MADV_F_NONE 0x0
+
+/* process_madvise(MADV_COLLAPSE) flags */
+#define MADV_F_COLLAPSE_LIMITS 0x1 /* respect system khugepaged/max_ptes_* sysfs limits */
+#define MADV_F_COLLAPSE_DEFRAG 0x2 /* force enable sync collapse + reclaim */
+#define MADV_F_COLLAPSE_MASK (MADV_F_COLLAPSE_LIMITS | MADV_F_COLLAPSE_DEFRAG)
+
/* compatibility flags */
#define MAP_FILE 0
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index e8156f15a3da..993de0c6eaa9 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -2942,7 +2942,7 @@ static int _madvise_collapse(struct mm_struct *mm,
int madvise_collapse(struct vm_area_struct *vma,
struct vm_area_struct **prev, unsigned long start,
- unsigned long end)
+ unsigned long end, unsigned int flags)
{
struct collapse_control cc;
gfp_t gfp;
@@ -2953,8 +2953,9 @@ int madvise_collapse(struct vm_area_struct *vma,
mmap_assert_locked(mm);
mmgrab(mm);
- collapse_control_init(&cc, /* enforce_pte_scan_limits= */ false);
- gfp = vma_thp_gfp_mask(vma);
+ collapse_control_init(&cc, flags & MADV_F_COLLAPSE_LIMITS);
+ gfp = vma_thp_gfp_mask(vma) | (flags & MADV_F_COLLAPSE_DEFRAG
+ ? __GFP_DIRECT_RECLAIM : 0);
lru_add_drain(); /* lru_add_drain_all() too heavy here */
error = _madvise_collapse(mm, vma, prev, start, end, gfp, &cc);
mmap_assert_locked(mm);
diff --git a/mm/madvise.c b/mm/madvise.c
index 292aa017c150..7d094d86d2f1 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -979,7 +979,7 @@ static long madvise_remove(struct vm_area_struct *vma,
static int madvise_vma_behavior(struct vm_area_struct *vma,
struct vm_area_struct **prev,
unsigned long start, unsigned long end,
- unsigned long behavior)
+ unsigned long behavior, unsigned int flags)
{
int error;
struct anon_vma_name *anon_name;
@@ -1048,7 +1048,7 @@ static int madvise_vma_behavior(struct vm_area_struct *vma,
goto out;
break;
case MADV_COLLAPSE:
- return madvise_collapse(vma, prev, start, end);
+ return madvise_collapse(vma, prev, start, end, flags);
}
anon_name = anon_vma_name(vma);
@@ -1160,13 +1160,19 @@ madvise_behavior_valid(int behavior)
}
static bool
-process_madvise_behavior_valid(int behavior)
+process_madvise_behavior_valid(int behavior, struct task_struct *task,
+ unsigned int flags)
{
switch (behavior) {
case MADV_COLD:
case MADV_PAGEOUT:
case MADV_WILLNEED:
- return true;
+ return flags == 0;
+ case MADV_COLLAPSE:
+ return (flags & ~MADV_F_COLLAPSE_MASK) == 0 &&
+ (capable(CAP_SYS_ADMIN) ||
+ (task == current) ||
+ (flags & MADV_F_COLLAPSE_LIMITS));
default:
return false;
}
@@ -1182,10 +1188,11 @@ process_madvise_behavior_valid(int behavior)
*/
static
int madvise_walk_vmas(struct mm_struct *mm, unsigned long start,
- unsigned long end, unsigned long arg,
+ unsigned long end, unsigned long arg, unsigned int flags,
int (*visit)(struct vm_area_struct *vma,
struct vm_area_struct **prev, unsigned long start,
- unsigned long end, unsigned long arg))
+ unsigned long end, unsigned long arg,
+ unsigned int flags))
{
struct vm_area_struct *vma;
struct vm_area_struct *prev;
@@ -1222,7 +1229,7 @@ int madvise_walk_vmas(struct mm_struct *mm, unsigned long start,
tmp = end;
/* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */
- error = visit(vma, &prev, start, tmp, arg);
+ error = visit(vma, &prev, start, tmp, arg, flags);
if (error)
return error;
start = tmp;
@@ -1285,7 +1292,7 @@ int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
return 0;
return madvise_walk_vmas(mm, start, end, (unsigned long)anon_name,
- madvise_vma_anon_name);
+ madvise_vma_anon_name, MADV_F_NONE);
}
#endif /* CONFIG_ANON_VMA_NAME */
/*
@@ -1359,7 +1366,8 @@ int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
* -EBADF - map exists, but area maps something that isn't a file.
* -EAGAIN - a kernel resource was temporarily unavailable.
*/
-int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior)
+int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in,
+ int behavior, unsigned int flags)
{
unsigned long end;
int error;
@@ -1401,8 +1409,8 @@ int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int beh
}
blk_start_plug(&plug);
- error = madvise_walk_vmas(mm, start, end, behavior,
- madvise_vma_behavior);
+ error = madvise_walk_vmas(mm, start, end, behavior, flags,
+ madvise_vma_behavior);
blk_finish_plug(&plug);
if (write)
mmap_write_unlock(mm);
@@ -1414,7 +1422,8 @@ int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int beh
SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
{
- return do_madvise(current->mm, start, len_in, behavior);
+ return do_madvise(current->mm, start, len_in, behavior,
+ MADV_F_NONE);
}
SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
@@ -1429,11 +1438,6 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
size_t total_len;
unsigned int f_flags;
- if (flags != 0) {
- ret = -EINVAL;
- goto out;
- }
-
ret = import_iovec(READ, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
if (ret < 0)
goto out;
@@ -1444,7 +1448,7 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
goto free_iov;
}
- if (!process_madvise_behavior_valid(behavior)) {
+ if (!process_madvise_behavior_valid(behavior, task, flags)) {
ret = -EINVAL;
goto release_task;
}
@@ -1470,7 +1474,7 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
while (iov_iter_count(&iter)) {
iovec = iov_iter_iovec(&iter);
ret = do_madvise(mm, (unsigned long)iovec.iov_base,
- iovec.iov_len, behavior);
+ iovec.iov_len, behavior, flags);
if (ret < 0)
break;
iov_iter_advance(&iter, iovec.iov_len);
--
2.35.1.616.g0bdcbb4464-goog
