The prototype of the new swapoff (without the quadratic complexity)
presently ignores the frontswap case. Pass the count of
pages_to_unuse down the page table walks in try_to_unuse(),
and return from the walk when the desired number of pages
has been swapped back in.
Signed-off-by: Kelley Nielsen <kelleynnn@xxxxxxxxx>
---
mm/shmem.c | 1 +
mm/swapfile.c | 53 +++++++++++++++++++++++++++++++++++++----------------
2 files changed, 38 insertions(+), 16 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index 2a7179c..e7a813f 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -629,6 +629,7 @@ static int shmem_unuse_inode(struct inode *inode, unsigned int type)
int entries = 0;
swp_entry_t entry;
unsigned int stype;
+
pgoff_t start = 0;
gfp = mapping_gfp_mask(mapping);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 966862c..cc3887a 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1146,7 +1146,7 @@ out_nolock:
static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end,
- unsigned int type)
+ unsigned int type, unsigned long pages_to_unuse)
{
struct page *page;
swp_entry_t entry;
@@ -1169,6 +1169,8 @@ static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
continue;
if (found_type != type)
continue;
+ if ((pages_to_unuse > 0) && (!frontswap_test(si, offset)))
+ continue;
swap_map = &si->swap_map[offset];
if (!swap_count(*swap_map))
@@ -1210,6 +1212,15 @@ static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
SetPageDirty(page);
unlock_page(page);
page_cache_release(page);
+ if (ret && pages_to_unuse > 0) {
+ pages_to_unuse--;
+ /*
+ * we've unused all we need for frontswap,
+ * so return special code to indicate this.
+ */
+ if (pages_to_unuse == 0)
+ return 2;
+ }
try_next:
pte = pte_offset_map(pmd, addr);
} while (pte++, addr += PAGE_SIZE, addr != end);
@@ -1220,7 +1231,7 @@ out:
static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud,
unsigned long addr, unsigned long end,
- unsigned int type)
+ unsigned int type, unsigned long pages_to_unuse)
{
pmd_t *pmd;
unsigned long next;
@@ -1231,8 +1242,9 @@ static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud,
next = pmd_addr_end(addr, end);
if (pmd_none_or_trans_huge_or_clear_bad(pmd))
continue;
- ret = unuse_pte_range(vma, pmd, addr, next, type);
- if (ret < 0)
+ ret = unuse_pte_range(vma, pmd, addr, next, type,
+ pages_to_unuse);
+ if (ret < 0 || ret == 2)
return ret;
} while (pmd++, addr = next, addr != end);
return 0;
@@ -1240,7 +1252,7 @@ static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud,
static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
unsigned long addr, unsigned long end,
- unsigned int type)
+ unsigned int type, unsigned long pages_to_unuse)
{
pud_t *pud;
unsigned long next;
@@ -1251,14 +1263,16 @@ static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
next = pud_addr_end(addr, end);
if (pud_none_or_clear_bad(pud))
continue;
- ret = unuse_pmd_range(vma, pud, addr, next, type);
- if (ret < 0)
+ ret = unuse_pmd_range(vma, pud, addr, next, type,
+ pages_to_unuse);
+ if (ret < 0 || ret == 2)
return ret;
} while (pud++, addr = next, addr != end);
return 0;
}
-static int unuse_vma(struct vm_area_struct *vma, unsigned int type)
+static int unuse_vma(struct vm_area_struct *vma, unsigned int type,
+ unsigned long pages_to_unuse)
{
pgd_t *pgd;
unsigned long addr, end, next;
@@ -1272,14 +1286,16 @@ static int unuse_vma(struct vm_area_struct *vma, unsigned int type)
next = pgd_addr_end(addr, end);
if (pgd_none_or_clear_bad(pgd))
continue;
- ret = unuse_pud_range(vma, pgd, addr, next, type);
- if (ret < 0)
+ ret = unuse_pud_range(vma, pgd, addr, next, type,
+ pages_to_unuse);
+ if (ret < 0 || ret == 2)
return ret;
} while (pgd++, addr = next, addr != end);
return 0;
}
-static int unuse_mm(struct mm_struct *mm, unsigned int type)
+static int unuse_mm(struct mm_struct *mm, unsigned int type,
+ unsigned long pages_to_unuse)
{
struct vm_area_struct *vma;
int ret = 0;
@@ -1287,7 +1303,7 @@ static int unuse_mm(struct mm_struct *mm, unsigned int type)
down_read(&mm->mmap_sem);
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (vma->anon_vma) {
- ret = unuse_vma(vma, type);
+ ret = unuse_vma(vma, type, pages_to_unuse);
if (ret)
break;
}
@@ -1342,7 +1358,6 @@ static unsigned int find_next_to_unuse(struct swap_info_struct *si,
return i;
}
-/* TODO: frontswap */
#define MAX_RETRIES 3
int try_to_unuse(unsigned int type, bool frontswap,
unsigned long pages_to_unuse)
@@ -1358,6 +1373,9 @@ int try_to_unuse(unsigned int type, bool frontswap,
unsigned int oldi = 0;
int retries = 0;
+ if (!frontswap)
+ pages_to_unuse = 0;
+
retry:
retval = shmem_unuse(type);
if (retval)
@@ -1381,7 +1399,8 @@ retry:
mmput(prev_mm);
prev_mm = mm;
- retval = unuse_mm(mm, type);
+ /* return code to stop and return */
+ retval = unuse_mm(mm, type, pages_to_unuse);
if (retval)
goto out_put;
@@ -1396,8 +1415,10 @@ retry:
out_put:
mmput(prev_mm);
- if (retval)
+ if (retval < 0)
goto out;
+ retval = 0;
+
while ((i = find_next_to_unuse(si, i, frontswap)) != 0) {
/*
* under global memory pressure, swap entries
@@ -1410,7 +1431,7 @@ out_put:
*/
if (i < oldi) {
retries++;
- if (retries > MAX_RETRIES)
+ if ((retries > MAX_RETRIES) || frontswap)
goto out;
goto retry;
}
--
1.8.3.2
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