static void *zcache_pampd_eph_create(char *data, size_t size, bool raw,
struct tmem_handle *th)
{
void *pampd = NULL, *cdata = data;
unsigned clen = size;
bool zero_filled = false;
struct page *page = (struct page *)(data), *newpage;
if (page_is_zero_filled(page)) {
clen = 0;
zero_filled = true;
inc_zcache_zero_filled_pages();
goto got_pampd;
}
if (!raw) {
zcache_compress(page, &cdata, &clen);
if (clen > zbud_max_buddy_size()) {
inc_zcache_compress_poor();
goto out;
}
} else {
BUG_ON(clen > zbud_max_buddy_size());
}
/* look for space via an existing match first */
pampd = (void *)zbud_match_prep(th, true, cdata, clen);
if (pampd != NULL)
goto got_pampd;
/* no match, now we need to find (or free up) a full page */
newpage = zcache_alloc_page();
if (newpage != NULL)
goto create_in_new_page;
inc_zcache_failed_getfreepages();
/* can't allocate a page, evict an ephemeral page via LRU */
newpage = zcache_evict_eph_pageframe();
if (newpage == NULL) {
inc_zcache_eph_ate_tail_failed();
goto out;
}
inc_zcache_eph_ate_tail();
create_in_new_page:
pampd = (void *)zbud_create_prep(th, true, cdata, clen, newpage);
BUG_ON(pampd == NULL);
inc_zcache_eph_pageframes();
got_pampd:
inc_zcache_eph_zbytes(clen);
inc_zcache_eph_zpages();
if (ramster_enabled && raw && !zero_filled)
ramster_count_foreign_pages(true, 1);
if (zero_filled)
pampd = (void *)ZERO_FILLED;
out:
return pampd;
}
static char *zbud_data(struct zbud_hdr *zh, unsigned size)
{
struct zbud_page *zbpg;
char *p;
unsigned budnum;
ASSERT_SENTINEL(zh, ZBH);
budnum = zbud_budnum(zh);
BUG_ON(size == 0 || size > zbud_max_buddy_size());
zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
ASSERT_SPINLOCK(&zbpg->lock);
p = (char *)zbpg;
if (budnum == 0)
p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
CHUNK_MASK);
else if (budnum == 1)
p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
return p;
}
static inline unsigned zbud_size_to_chunks(unsigned size)
{
BUG_ON(size == 0 || size > zbud_max_buddy_size());
return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
}