si->cluster_nr = SWAPFILE_CLUSTER - 1;
goto checks;
}
- if (si->flags & SWP_DISCARDABLE) {
+ if (si->flags & SWP_PAGE_DISCARD) {
/*
* Start range check on racing allocations, in case
* they overlap the cluster we eventually decide on
if (si->lowest_alloc) {
/*
- * Only set when SWP_DISCARDABLE, and there's a scan
+ * Only set when SWP_PAGE_DISCARD, and there's a scan
* for a free cluster in progress or just completed.
*/
if (found_free_cluster) {
}
#endif /* CONFIG_HIBERNATION */
+static inline int maybe_same_pte(pte_t pte, pte_t swp_pte)
+{
+#ifdef CONFIG_MEM_SOFT_DIRTY
+ /*
+ * When pte keeps soft dirty bit the pte generated
+ * from swap entry does not has it, still it's same
+ * pte from logical point of view.
+ */
+ pte_t swp_pte_dirty = pte_swp_mksoft_dirty(swp_pte);
+ return pte_same(pte, swp_pte) || pte_same(pte, swp_pte_dirty);
+#else
+ return pte_same(pte, swp_pte);
+#endif
+}
+
/*
* No need to decide whether this PTE shares the swap entry with others,
* just let do_wp_page work it out if a write is requested later - to
}
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
- if (unlikely(!pte_same(*pte, swp_entry_to_pte(entry)))) {
+ if (unlikely(!maybe_same_pte(*pte, swp_entry_to_pte(entry)))) {
mem_cgroup_cancel_charge_swapin(memcg);
ret = 0;
goto out;
* swapoff spends a _lot_ of time in this loop!
* Test inline before going to call unuse_pte.
*/
- if (unlikely(pte_same(*pte, swp_pte))) {
+ if (unlikely(maybe_same_pte(*pte, swp_pte))) {
pte_unmap(pte);
ret = unuse_pte(vma, pmd, addr, entry, page);
if (ret)
return nr_extents;
}
+/*
+ * Helper to sys_swapon determining if a given swap
+ * backing device queue supports DISCARD operations.
+ */
+static bool swap_discardable(struct swap_info_struct *si)
+{
+ struct request_queue *q = bdev_get_queue(si->bdev);
+
+ if (!q || !blk_queue_discard(q))
+ return false;
+
+ return true;
+}
+
SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
{
struct swap_info_struct *p;
p->flags |= SWP_SOLIDSTATE;
p->cluster_next = 1 + (prandom_u32() % p->highest_bit);
}
- if ((swap_flags & SWAP_FLAG_DISCARD) && discard_swap(p) == 0)
- p->flags |= SWP_DISCARDABLE;
+
+ if ((swap_flags & SWAP_FLAG_DISCARD) && swap_discardable(p)) {
+ /*
+ * When discard is enabled for swap with no particular
+ * policy flagged, we set all swap discard flags here in
+ * order to sustain backward compatibility with older
+ * swapon(8) releases.
+ */
+ p->flags |= (SWP_DISCARDABLE | SWP_AREA_DISCARD |
+ SWP_PAGE_DISCARD);
+
+ /*
+ * By flagging sys_swapon, a sysadmin can tell us to
+ * either do single-time area discards only, or to just
+ * perform discards for released swap page-clusters.
+ * Now it's time to adjust the p->flags accordingly.
+ */
+ if (swap_flags & SWAP_FLAG_DISCARD_ONCE)
+ p->flags &= ~SWP_PAGE_DISCARD;
+ else if (swap_flags & SWAP_FLAG_DISCARD_PAGES)
+ p->flags &= ~SWP_AREA_DISCARD;
+
+ /* issue a swapon-time discard if it's still required */
+ if (p->flags & SWP_AREA_DISCARD) {
+ int err = discard_swap(p);
+ if (unlikely(err))
+ printk(KERN_ERR
+ "swapon: discard_swap(%p): %d\n",
+ p, err);
+ }
+ }
}
mutex_lock(&swapon_mutex);
enable_swap_info(p, prio, swap_map, frontswap_map);
printk(KERN_INFO "Adding %uk swap on %s. "
- "Priority:%d extents:%d across:%lluk %s%s%s\n",
+ "Priority:%d extents:%d across:%lluk %s%s%s%s%s\n",
p->pages<<(PAGE_SHIFT-10), name->name, p->prio,
nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10),
(p->flags & SWP_SOLIDSTATE) ? "SS" : "",
(p->flags & SWP_DISCARDABLE) ? "D" : "",
+ (p->flags & SWP_AREA_DISCARD) ? "s" : "",
+ (p->flags & SWP_PAGE_DISCARD) ? "c" : "",
(frontswap_map) ? "FS" : "");
mutex_unlock(&swapon_mutex);