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Subject[PATCH v5 3/7] mm: check fatal signal pending of target process
Date
Bail out to prevent unnecessary CPU overhead if target process ha
pending fatal signal during MADV_COLD| MADV_PAGEOUT operation.

Signed-off-by: Minchan Kim <minchan@kernel.org>
---
mm/madvise.c | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index fadc8d758a46..fca3a9e9bd39 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -36,6 +36,7 @@
struct madvise_walk_private {
struct mmu_gather *tlb;
bool pageout;
+ struct task_struct *task;
};

/*
@@ -316,6 +317,9 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
if (fatal_signal_pending(current))
return -EINTR;

+ if (fatal_signal_pending(private->task))
+ return -EINTR;
+
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
if (pmd_trans_huge(*pmd)) {
pmd_t orig_pmd;
@@ -471,12 +475,14 @@ static const struct mm_walk_ops cold_walk_ops = {
};

static void madvise_cold_page_range(struct mmu_gather *tlb,
+ struct task_struct *task,
struct vm_area_struct *vma,
unsigned long addr, unsigned long end)
{
struct madvise_walk_private walk_private = {
.pageout = false,
.tlb = tlb,
+ .task = task,
};

tlb_start_vma(tlb, vma);
@@ -484,7 +490,8 @@ static void madvise_cold_page_range(struct mmu_gather *tlb,
tlb_end_vma(tlb, vma);
}

-static long madvise_cold(struct vm_area_struct *vma,
+static long madvise_cold(struct task_struct *task,
+ struct vm_area_struct *vma,
struct vm_area_struct **prev,
unsigned long start_addr, unsigned long end_addr)
{
@@ -497,19 +504,21 @@ static long madvise_cold(struct vm_area_struct *vma,

lru_add_drain();
tlb_gather_mmu(&tlb, mm, start_addr, end_addr);
- madvise_cold_page_range(&tlb, vma, start_addr, end_addr);
+ madvise_cold_page_range(&tlb, task, vma, start_addr, end_addr);
tlb_finish_mmu(&tlb, start_addr, end_addr);

return 0;
}

static void madvise_pageout_page_range(struct mmu_gather *tlb,
+ struct task_struct *task,
struct vm_area_struct *vma,
unsigned long addr, unsigned long end)
{
struct madvise_walk_private walk_private = {
.pageout = true,
.tlb = tlb,
+ .task = task,
};

tlb_start_vma(tlb, vma);
@@ -533,7 +542,8 @@ static inline bool can_do_pageout(struct vm_area_struct *vma)
inode_permission(file_inode(vma->vm_file), MAY_WRITE) == 0;
}

-static long madvise_pageout(struct vm_area_struct *vma,
+static long madvise_pageout(struct task_struct *task,
+ struct vm_area_struct *vma,
struct vm_area_struct **prev,
unsigned long start_addr, unsigned long end_addr)
{
@@ -549,7 +559,7 @@ static long madvise_pageout(struct vm_area_struct *vma,

lru_add_drain();
tlb_gather_mmu(&tlb, mm, start_addr, end_addr);
- madvise_pageout_page_range(&tlb, vma, start_addr, end_addr);
+ madvise_pageout_page_range(&tlb, task, vma, start_addr, end_addr);
tlb_finish_mmu(&tlb, start_addr, end_addr);

return 0;
@@ -929,7 +939,8 @@ static int madvise_inject_error(int behavior,
#endif

static long
-madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
+madvise_vma(struct task_struct *task, struct vm_area_struct *vma,
+ struct vm_area_struct **prev,
unsigned long start, unsigned long end, int behavior)
{
switch (behavior) {
@@ -938,9 +949,9 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
case MADV_WILLNEED:
return madvise_willneed(vma, prev, start, end);
case MADV_COLD:
- return madvise_cold(vma, prev, start, end);
+ return madvise_cold(task, vma, prev, start, end);
case MADV_PAGEOUT:
- return madvise_pageout(vma, prev, start, end);
+ return madvise_pageout(task, vma, prev, start, end);
case MADV_FREE:
case MADV_DONTNEED:
return madvise_dontneed_free(vma, prev, start, end, behavior);
@@ -1140,7 +1151,7 @@ int do_madvise(struct task_struct *task, struct mm_struct *mm,
tmp = end;

/* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */
- error = madvise_vma(vma, &prev, start, tmp, behavior);
+ error = madvise_vma(task, vma, &prev, start, tmp, behavior);
if (error)
goto out;
start = tmp;
--
2.25.0.265.gbab2e86ba0-goog
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