mm: simplify try_to_unuse

Remove the unused frontswap and pages_to_unuse arguments, and mark the
function static now that the caller in frontswap is gone.

[akpm@linux-foundation.org: fix shmem_unuse() stub, per Matthew]

Link: https://lkml.kernel.org/r/20211224062246.1258487-9-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Konrad Rzeszutek Wilk <Konrad.wilk@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h
index 73d7beb..a9817d4 100644 (file)
--- a/include/linux/frontswap.h
+++ b/include/linux/frontswap.h
@@ -7,13 +7,6 @@
 #include <linux/bitops.h>
 #include <linux/jump_label.h>
 
-/*
- * Return code to denote that requested number of
- * frontswap pages are unused(moved to page cache).
- * Used in shmem_unuse and try_to_unuse.
- */
-#define FRONTSWAP_PAGES_UNUSED 2
-
 struct frontswap_ops {
        void (*init)(unsigned); /* this swap type was just swapon'ed */
        int (*store)(unsigned, pgoff_t, struct page *); /* store a page */

diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 166158b..e65b80e 100644 (file)
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -83,8 +83,7 @@ extern void shmem_unlock_mapping(struct address_space *mapping);
 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
                                        pgoff_t index, gfp_t gfp_mask);
 extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
-extern int shmem_unuse(unsigned int type, bool frontswap,
-                      unsigned long *fs_pages_to_unuse);
+int shmem_unuse(unsigned int type);
 
 extern bool shmem_is_huge(struct vm_area_struct *vma,
                          struct inode *inode, pgoff_t index);

diff --git a/include/linux/swapfile.h b/include/linux/swapfile.h
index e06febf..809cd01 100644 (file)
--- a/include/linux/swapfile.h
+++ b/include/linux/swapfile.h
@@ -9,7 +9,6 @@
 extern spinlock_t swap_lock;
 extern struct plist_head swap_active_head;
 extern struct swap_info_struct *swap_info[];
-extern int try_to_unuse(unsigned int, bool, unsigned long);
 extern unsigned long generic_max_swapfile_size(void);
 extern unsigned long max_swapfile_size(void);
 

diff --git a/mm/shmem.c b/mm/shmem.c
index 66909ef..a09b29e 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -36,7 +36,6 @@
 #include <linux/uio.h>
 #include <linux/khugepaged.h>
 #include <linux/hugetlb.h>
-#include <linux/frontswap.h>
 #include <linux/fs_parser.h>
 #include <linux/swapfile.h>
 
@@ -1152,7 +1151,7 @@ static void shmem_evict_inode(struct inode *inode)
 static int shmem_find_swap_entries(struct address_space *mapping,
                                   pgoff_t start, unsigned int nr_entries,
                                   struct page **entries, pgoff_t *indices,
-                                  unsigned int type, bool frontswap)
+                                  unsigned int type)
 {
        XA_STATE(xas, &mapping->i_pages, start);
        struct page *page;
@@ -1173,9 +1172,6 @@ static int shmem_find_swap_entries(struct address_space *mapping,
                entry = radix_to_swp_entry(page);
                if (swp_type(entry) != type)
                        continue;
-               if (frontswap &&
-                   !frontswap_test(swap_info[type], swp_offset(entry)))
-                       continue;
 
                indices[ret] = xas.xa_index;
                entries[ret] = page;
@@ -1228,26 +1224,20 @@ static int shmem_unuse_swap_entries(struct inode *inode, struct pagevec pvec,
 /*
  * If swap found in inode, free it and move page from swapcache to filecache.
  */
-static int shmem_unuse_inode(struct inode *inode, unsigned int type,
-                            bool frontswap, unsigned long *fs_pages_to_unuse)
+static int shmem_unuse_inode(struct inode *inode, unsigned int type)
 {
        struct address_space *mapping = inode->i_mapping;
        pgoff_t start = 0;
        struct pagevec pvec;
        pgoff_t indices[PAGEVEC_SIZE];
-       bool frontswap_partial = (frontswap && *fs_pages_to_unuse > 0);
        int ret = 0;
 
        pagevec_init(&pvec);
        do {
                unsigned int nr_entries = PAGEVEC_SIZE;
 
-               if (frontswap_partial && *fs_pages_to_unuse < PAGEVEC_SIZE)
-                       nr_entries = *fs_pages_to_unuse;
-
                pvec.nr = shmem_find_swap_entries(mapping, start, nr_entries,
-                                                 pvec.pages, indices,
-                                                 type, frontswap);
+                                                 pvec.pages, indices, type);
                if (pvec.nr == 0) {
                        ret = 0;
                        break;
@@ -1257,14 +1247,6 @@ static int shmem_unuse_inode(struct inode *inode, unsigned int type,
                if (ret < 0)
                        break;
 
-               if (frontswap_partial) {
-                       *fs_pages_to_unuse -= ret;
-                       if (*fs_pages_to_unuse == 0) {
-                               ret = FRONTSWAP_PAGES_UNUSED;
-                               break;
-                       }
-               }
-
                start = indices[pvec.nr - 1];
        } while (true);
 
@@ -1276,8 +1258,7 @@ static int shmem_unuse_inode(struct inode *inode, unsigned int type,
  * device 'type' back into memory, so the swap device can be
  * unused.
  */
-int shmem_unuse(unsigned int type, bool frontswap,
-               unsigned long *fs_pages_to_unuse)
+int shmem_unuse(unsigned int type)
 {
        struct shmem_inode_info *info, *next;
        int error = 0;
@@ -1300,8 +1281,7 @@ int shmem_unuse(unsigned int type, bool frontswap,
                atomic_inc(&info->stop_eviction);
                mutex_unlock(&shmem_swaplist_mutex);
 
-               error = shmem_unuse_inode(&info->vfs_inode, type, frontswap,
-                                         fs_pages_to_unuse);
+               error = shmem_unuse_inode(&info->vfs_inode, type);
                cond_resched();
 
                mutex_lock(&shmem_swaplist_mutex);
@@ -4015,8 +3995,7 @@ int __init shmem_init(void)
        return 0;
 }
 
-int shmem_unuse(unsigned int type, bool frontswap,
-               unsigned long *fs_pages_to_unuse)
+int shmem_unuse(unsigned int type)
 {
        return 0;
 }

diff --git a/mm/swapfile.c b/mm/swapfile.c
index df5930c..82342c7 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1923,8 +1923,7 @@ out:
 
 static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
                        unsigned long addr, unsigned long end,
-                       unsigned int type, bool frontswap,
-                       unsigned long *fs_pages_to_unuse)
+                       unsigned int type)
 {
        struct page *page;
        swp_entry_t entry;
@@ -1945,9 +1944,6 @@ static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
                        continue;
 
                offset = swp_offset(entry);
-               if (frontswap && !frontswap_test(si, offset))
-                       continue;
-
                pte_unmap(pte);
                swap_map = &si->swap_map[offset];
                page = lookup_swap_cache(entry, vma, addr);
@@ -1979,11 +1975,6 @@ static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
                try_to_free_swap(page);
                unlock_page(page);
                put_page(page);
-
-               if (*fs_pages_to_unuse && !--(*fs_pages_to_unuse)) {
-                       ret = FRONTSWAP_PAGES_UNUSED;
-                       goto out;
-               }
 try_next:
                pte = pte_offset_map(pmd, addr);
        } while (pte++, addr += PAGE_SIZE, addr != end);
@@ -1996,8 +1987,7 @@ out:
 
 static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud,
                                unsigned long addr, unsigned long end,
-                               unsigned int type, bool frontswap,
-                               unsigned long *fs_pages_to_unuse)
+                               unsigned int type)
 {
        pmd_t *pmd;
        unsigned long next;
@@ -2009,8 +1999,7 @@ 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,
-                                     frontswap, fs_pages_to_unuse);
+               ret = unuse_pte_range(vma, pmd, addr, next, type);
                if (ret)
                        return ret;
        } while (pmd++, addr = next, addr != end);
@@ -2019,8 +2008,7 @@ 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, p4d_t *p4d,
                                unsigned long addr, unsigned long end,
-                               unsigned int type, bool frontswap,
-                               unsigned long *fs_pages_to_unuse)
+                               unsigned int type)
 {
        pud_t *pud;
        unsigned long next;
@@ -2031,8 +2019,7 @@ static inline int unuse_pud_range(struct vm_area_struct *vma, p4d_t *p4d,
                next = pud_addr_end(addr, end);
                if (pud_none_or_clear_bad(pud))
                        continue;
-               ret = unuse_pmd_range(vma, pud, addr, next, type,
-                                     frontswap, fs_pages_to_unuse);
+               ret = unuse_pmd_range(vma, pud, addr, next, type);
                if (ret)
                        return ret;
        } while (pud++, addr = next, addr != end);
@@ -2041,8 +2028,7 @@ static inline int unuse_pud_range(struct vm_area_struct *vma, p4d_t *p4d,
 
 static inline int unuse_p4d_range(struct vm_area_struct *vma, pgd_t *pgd,
                                unsigned long addr, unsigned long end,
-                               unsigned int type, bool frontswap,
-                               unsigned long *fs_pages_to_unuse)
+                               unsigned int type)
 {
        p4d_t *p4d;
        unsigned long next;
@@ -2053,16 +2039,14 @@ static inline int unuse_p4d_range(struct vm_area_struct *vma, pgd_t *pgd,
                next = p4d_addr_end(addr, end);
                if (p4d_none_or_clear_bad(p4d))
                        continue;
-               ret = unuse_pud_range(vma, p4d, addr, next, type,
-                                     frontswap, fs_pages_to_unuse);
+               ret = unuse_pud_range(vma, p4d, addr, next, type);
                if (ret)
                        return ret;
        } while (p4d++, addr = next, addr != end);
        return 0;
 }
 
-static int unuse_vma(struct vm_area_struct *vma, unsigned int type,
-                    bool frontswap, unsigned long *fs_pages_to_unuse)
+static int unuse_vma(struct vm_area_struct *vma, unsigned int type)
 {
        pgd_t *pgd;
        unsigned long addr, end, next;
@@ -2076,16 +2060,14 @@ 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_p4d_range(vma, pgd, addr, next, type,
-                                     frontswap, fs_pages_to_unuse);
+               ret = unuse_p4d_range(vma, pgd, addr, next, type);
                if (ret)
                        return ret;
        } while (pgd++, addr = next, addr != end);
        return 0;
 }
 
-static int unuse_mm(struct mm_struct *mm, unsigned int type,
-                   bool frontswap, unsigned long *fs_pages_to_unuse)
+static int unuse_mm(struct mm_struct *mm, unsigned int type)
 {
        struct vm_area_struct *vma;
        int ret = 0;
@@ -2093,8 +2075,7 @@ static int unuse_mm(struct mm_struct *mm, unsigned int type,
        mmap_read_lock(mm);
        for (vma = mm->mmap; vma; vma = vma->vm_next) {
                if (vma->anon_vma) {
-                       ret = unuse_vma(vma, type, frontswap,
-                                       fs_pages_to_unuse);
+                       ret = unuse_vma(vma, type);
                        if (ret)
                                break;
                }
@@ -2110,7 +2091,7 @@ static int unuse_mm(struct mm_struct *mm, unsigned int type,
  * if there are no inuse entries after prev till end of the map.
  */
 static unsigned int find_next_to_unuse(struct swap_info_struct *si,
-                                       unsigned int prev, bool frontswap)
+                                       unsigned int prev)
 {
        unsigned int i;
        unsigned char count;
@@ -2124,8 +2105,7 @@ static unsigned int find_next_to_unuse(struct swap_info_struct *si,
        for (i = prev + 1; i < si->max; i++) {
                count = READ_ONCE(si->swap_map[i]);
                if (count && swap_count(count) != SWAP_MAP_BAD)
-                       if (!frontswap || frontswap_test(si, i))
-                               break;
+                       break;
                if ((i % LATENCY_LIMIT) == 0)
                        cond_resched();
        }
@@ -2136,12 +2116,7 @@ static unsigned int find_next_to_unuse(struct swap_info_struct *si,
        return i;
 }
 
-/*
- * If the boolean frontswap is true, only unuse pages_to_unuse pages;
- * pages_to_unuse==0 means all pages; ignored if frontswap is false
- */
-int try_to_unuse(unsigned int type, bool frontswap,
-                unsigned long pages_to_unuse)
+static int try_to_unuse(unsigned int type)
 {
        struct mm_struct *prev_mm;
        struct mm_struct *mm;
@@ -2155,13 +2130,10 @@ int try_to_unuse(unsigned int type, bool frontswap,
        if (!READ_ONCE(si->inuse_pages))
                return 0;
 
-       if (!frontswap)
-               pages_to_unuse = 0;
-
 retry:
-       retval = shmem_unuse(type, frontswap, &pages_to_unuse);
+       retval = shmem_unuse(type);
        if (retval)
-               goto out;
+               return retval;
 
        prev_mm = &init_mm;
        mmget(prev_mm);
@@ -2178,11 +2150,10 @@ retry:
                spin_unlock(&mmlist_lock);
                mmput(prev_mm);
                prev_mm = mm;
-               retval = unuse_mm(mm, type, frontswap, &pages_to_unuse);
-
+               retval = unuse_mm(mm, type);
                if (retval) {
                        mmput(prev_mm);
-                       goto out;
+                       return retval;
                }
 
                /*
@@ -2199,7 +2170,7 @@ retry:
        i = 0;
        while (READ_ONCE(si->inuse_pages) &&
               !signal_pending(current) &&
-              (i = find_next_to_unuse(si, i, frontswap)) != 0) {
+              (i = find_next_to_unuse(si, i)) != 0) {
 
                entry = swp_entry(type, i);
                page = find_get_page(swap_address_space(entry), i);
@@ -2217,14 +2188,6 @@ retry:
                try_to_free_swap(page);
                unlock_page(page);
                put_page(page);
-
-               /*
-                * For frontswap, we just need to unuse pages_to_unuse, if
-                * it was specified. Need not check frontswap again here as
-                * we already zeroed out pages_to_unuse if not frontswap.
-                */
-               if (pages_to_unuse && --pages_to_unuse == 0)
-                       goto out;
        }
 
        /*
@@ -2242,10 +2205,10 @@ retry:
        if (READ_ONCE(si->inuse_pages)) {
                if (!signal_pending(current))
                        goto retry;
-               retval = -EINTR;
+               return -EINTR;
        }
-out:
-       return (retval == FRONTSWAP_PAGES_UNUSED) ? 0 : retval;
+
+       return 0;
 }
 
 /*
@@ -2577,7 +2540,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
        disable_swap_slots_cache_lock();
 
        set_current_oom_origin();
-       err = try_to_unuse(p->type, false, 0); /* force unuse all pages */
+       err = try_to_unuse(p->type);
        clear_current_oom_origin();
 
        if (err) {