diff options
Diffstat (limited to 'drivers/staging/ramster/zcache-main.c')
| -rw-r--r-- | drivers/staging/ramster/zcache-main.c | 3320 |
1 files changed, 3320 insertions, 0 deletions
diff --git a/drivers/staging/ramster/zcache-main.c b/drivers/staging/ramster/zcache-main.c new file mode 100644 index 0000000..68b2e05 --- /dev/null +++ b/drivers/staging/ramster/zcache-main.c @@ -0,0 +1,3320 @@ +/* + * zcache.c + * + * Copyright (c) 2010-2012, Dan Magenheimer, Oracle Corp. + * Copyright (c) 2010,2011, Nitin Gupta + * + * Zcache provides an in-kernel "host implementation" for transcendent memory + * and, thus indirectly, for cleancache and frontswap. Zcache includes two + * page-accessible memory [1] interfaces, both utilizing lzo1x compression: + * 1) "compression buddies" ("zbud") is used for ephemeral pages + * 2) xvmalloc is used for persistent pages. + * Xvmalloc (based on the TLSF allocator) has very low fragmentation + * so maximizes space efficiency, while zbud allows pairs (and potentially, + * in the future, more than a pair of) compressed pages to be closely linked + * so that reclaiming can be done via the kernel's physical-page-oriented + * "shrinker" interface. + * + * [1] For a definition of page-accessible memory (aka PAM), see: + * http://marc.info/?l=linux-mm&m=127811271605009 + * RAMSTER TODO: + * - handle remotifying of buddied pages (see zbud_remotify_zbpg) + * - kernel boot params: nocleancache/nofrontswap don't always work?!? + */ + +#include <linux/module.h> +#include <linux/cpu.h> +#include <linux/highmem.h> +#include <linux/list.h> +#include <linux/lzo.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/types.h> +#include <linux/atomic.h> +#include <linux/math64.h> +#include "tmem.h" +#include "zcache.h" +#include "ramster.h" +#include "cluster/tcp.h" + +#include "xvmalloc.h" /* temporary until change to zsmalloc */ + +#define RAMSTER_TESTING + +#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP)) +#error "ramster is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP" +#endif +#ifdef CONFIG_CLEANCACHE +#include <linux/cleancache.h> +#endif +#ifdef CONFIG_FRONTSWAP +#include <linux/frontswap.h> +#endif + +enum ramster_remotify_op { + RAMSTER_REMOTIFY_EPH_PUT, + RAMSTER_REMOTIFY_PERS_PUT, + RAMSTER_REMOTIFY_FLUSH_PAGE, + RAMSTER_REMOTIFY_FLUSH_OBJ, + RAMSTER_INTRANSIT_PERS +}; + +struct ramster_remotify_hdr { + enum ramster_remotify_op op; + struct list_head list; +}; + +#define ZBH_SENTINEL 0x43214321 +#define ZBPG_SENTINEL 0xdeadbeef + +#define ZBUD_MAX_BUDS 2 + +struct zbud_hdr { + struct ramster_remotify_hdr rem_op; + uint16_t client_id; + uint16_t pool_id; + struct tmem_oid oid; + uint32_t index; + uint16_t size; /* compressed size in bytes, zero means unused */ + DECL_SENTINEL +}; + +#define ZVH_SENTINEL 0x43214321 +static const int zv_max_page_size = (PAGE_SIZE / 8) * 7; + +struct zv_hdr { + struct ramster_remotify_hdr rem_op; + uint16_t client_id; + uint16_t pool_id; + struct tmem_oid oid; + uint32_t index; + DECL_SENTINEL +}; + +struct flushlist_node { + struct ramster_remotify_hdr rem_op; + struct tmem_xhandle xh; +}; + +union { + struct ramster_remotify_hdr rem_op; + struct zv_hdr zv; + struct zbud_hdr zbud; + struct flushlist_node flist; +} remotify_list_node; + +static LIST_HEAD(zcache_rem_op_list); +static DEFINE_SPINLOCK(zcache_rem_op_list_lock); + +#if 0 +/* this is more aggressive but may cause other problems? */ +#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN) +#else +#define ZCACHE_GFP_MASK \ + (__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC) +#endif + +#define MAX_POOLS_PER_CLIENT 16 + +#define MAX_CLIENTS 16 +#define LOCAL_CLIENT ((uint16_t)-1) + +MODULE_LICENSE("GPL"); + +struct zcache_client { + struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT]; + struct xv_pool *xvpool; + bool allocated; + atomic_t refcount; +}; + +static struct zcache_client zcache_host; +static struct zcache_client zcache_clients[MAX_CLIENTS]; + +static inline uint16_t get_client_id_from_client(struct zcache_client *cli) +{ + BUG_ON(cli == NULL); + if (cli == &zcache_host) + return LOCAL_CLIENT; + return cli - &zcache_clients[0]; +} + +static inline bool is_local_client(struct zcache_client *cli) +{ + return cli == &zcache_host; +} + +/********** + * Compression buddies ("zbud") provides for packing two (or, possibly + * in the future, more) compressed ephemeral pages into a single "raw" + * (physical) page and tracking them with data structures so that + * the raw pages can be easily reclaimed. + * + * A zbud page ("zbpg") is an aligned page containing a list_head, + * a lock, and two "zbud headers". The remainder of the physical + * page is divided up into aligned 64-byte "chunks" which contain + * the compressed data for zero, one, or two zbuds. Each zbpg + * resides on: (1) an "unused list" if it has no zbuds; (2) a + * "buddied" list if it is fully populated with two zbuds; or + * (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks + * the one unbuddied zbud uses. The data inside a zbpg cannot be + * read or written unless the zbpg's lock is held. + */ + +struct zbud_page { + struct list_head bud_list; + spinlock_t lock; + struct zbud_hdr buddy[ZBUD_MAX_BUDS]; + DECL_SENTINEL + /* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */ +}; + +#define CHUNK_SHIFT 6 +#define CHUNK_SIZE (1 << CHUNK_SHIFT) +#define CHUNK_MASK (~(CHUNK_SIZE-1)) +#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \ + CHUNK_MASK) >> CHUNK_SHIFT) +#define MAX_CHUNK (NCHUNKS-1) + +static struct { + struct list_head list; + unsigned count; +} zbud_unbuddied[NCHUNKS]; +/* list N contains pages with N chunks USED and NCHUNKS-N unused */ +/* element 0 is never used but optimizing that isn't worth it */ +static unsigned long zbud_cumul_chunk_counts[NCHUNKS]; + +struct list_head zbud_buddied_list; +static unsigned long zcache_zbud_buddied_count; + +/* protects the buddied list and all unbuddied lists */ +static DEFINE_SPINLOCK(zbud_budlists_spinlock); + +static atomic_t zcache_zbud_curr_raw_pages; +static atomic_t zcache_zbud_curr_zpages; +static unsigned long zcache_zbud_curr_zbytes; +static unsigned long zcache_zbud_cumul_zpages; +static unsigned long zcache_zbud_cumul_zbytes; +static unsigned long zcache_compress_poor; +static unsigned long zcache_policy_percent_exceeded; +static unsigned long zcache_mean_compress_poor; + +/* + * RAMster counters + * - Remote pages are pages with a local pampd but the data is remote + * - Foreign pages are pages stored locally but belonging to another node + */ +static atomic_t ramster_remote_pers_pages = ATOMIC_INIT(0); +static unsigned long ramster_pers_remotify_enable; +static unsigned long ramster_eph_remotify_enable; +static unsigned long ramster_eph_pages_remoted; +static unsigned long ramster_eph_pages_remote_failed; +static unsigned long ramster_pers_pages_remoted; +static unsigned long ramster_pers_pages_remote_failed; +static unsigned long ramster_pers_pages_remote_nomem; +static unsigned long ramster_remote_objects_flushed; +static unsigned long ramster_remote_object_flushes_failed; +static unsigned long ramster_remote_pages_flushed; +static unsigned long ramster_remote_page_flushes_failed; +static unsigned long ramster_remote_eph_pages_succ_get; +static unsigned long ramster_remote_pers_pages_succ_get; +static unsigned long ramster_remote_eph_pages_unsucc_get; +static unsigned long ramster_remote_pers_pages_unsucc_get; +static atomic_t ramster_curr_flnode_count = ATOMIC_INIT(0); +static unsigned long ramster_curr_flnode_count_max; +static atomic_t ramster_foreign_eph_pampd_count = ATOMIC_INIT(0); +static unsigned long ramster_foreign_eph_pampd_count_max; +static atomic_t ramster_foreign_pers_pampd_count = ATOMIC_INIT(0); +static unsigned long ramster_foreign_pers_pampd_count_max; + +/* forward references */ +static void *zcache_get_free_page(void); +static void zcache_free_page(void *p); + +/* + * zbud helper functions + */ + +static inline unsigned zbud_max_buddy_size(void) +{ + return MAX_CHUNK << CHUNK_SHIFT; +} + +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; +} + +static inline int zbud_budnum(struct zbud_hdr *zh) +{ + unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1); + struct zbud_page *zbpg = NULL; + unsigned budnum = -1U; + int i; + + for (i = 0; i < ZBUD_MAX_BUDS; i++) + if (offset == offsetof(typeof(*zbpg), buddy[i])) { + budnum = i; + break; + } + BUG_ON(budnum == -1U); + return budnum; +} + +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 void zbud_copy_from_pampd(char *data, size_t *size, struct zbud_hdr *zh) +{ + struct zbud_page *zbpg; + char *p; + unsigned budnum; + + ASSERT_SENTINEL(zh, ZBH); + budnum = zbud_budnum(zh); + zbpg = container_of(zh, struct zbud_page, buddy[budnum]); + spin_lock(&zbpg->lock); + BUG_ON(zh->size > *size); + p = (char *)zbpg; + if (budnum == 0) + p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) & + CHUNK_MASK); + else if (budnum == 1) + p += PAGE_SIZE - ((zh->size + CHUNK_SIZE - 1) & CHUNK_MASK); + /* client should be filled in by caller */ + memcpy(data, p, zh->size); + *size = zh->size; + spin_unlock(&zbpg->lock); +} + +/* + * zbud raw page management + */ + +static struct zbud_page *zbud_alloc_raw_page(void) +{ + struct zbud_page *zbpg = NULL; + struct zbud_hdr *zh0, *zh1; + zbpg = zcache_get_free_page(); + if (likely(zbpg != NULL)) { + INIT_LIST_HEAD(&zbpg->bud_list); + zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1]; + spin_lock_init(&zbpg->lock); + atomic_inc(&zcache_zbud_curr_raw_pages); + INIT_LIST_HEAD(&zbpg->bud_list); + SET_SENTINEL(zbpg, ZBPG); + zh0->size = 0; zh1->size = 0; + tmem_oid_set_invalid(&zh0->oid); + tmem_oid_set_invalid(&zh1->oid); + } + return zbpg; +} + +static void zbud_free_raw_page(struct zbud_page *zbpg) +{ + struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1]; + + ASSERT_SENTINEL(zbpg, ZBPG); + BUG_ON(!list_empty(&zbpg->bud_list)); + ASSERT_SPINLOCK(&zbpg->lock); + BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid)); + BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid)); + INVERT_SENTINEL(zbpg, ZBPG); + spin_unlock(&zbpg->lock); + atomic_dec(&zcache_zbud_curr_raw_pages); + zcache_free_page(zbpg); +} + +/* + * core zbud handling routines + */ + +static unsigned zbud_free(struct zbud_hdr *zh) +{ + unsigned size; + + ASSERT_SENTINEL(zh, ZBH); + BUG_ON(!tmem_oid_valid(&zh->oid)); + size = zh->size; + BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size()); + zh->size = 0; + tmem_oid_set_invalid(&zh->oid); + INVERT_SENTINEL(zh, ZBH); + zcache_zbud_curr_zbytes -= size; + atomic_dec(&zcache_zbud_curr_zpages); + return size; +} + +static void zbud_free_and_delist(struct zbud_hdr *zh) +{ + unsigned chunks; + struct zbud_hdr *zh_other; + unsigned budnum = zbud_budnum(zh), size; + struct zbud_page *zbpg = + container_of(zh, struct zbud_page, buddy[budnum]); + + /* FIXME, should be BUG_ON, pool destruction path doesn't disable + * interrupts tmem_destroy_pool()->tmem_pampd_destroy_all_in_obj()-> + * tmem_objnode_node_destroy()-> zcache_pampd_free() */ + WARN_ON(!irqs_disabled()); + spin_lock(&zbpg->lock); + if (list_empty(&zbpg->bud_list)) { + /* ignore zombie page... see zbud_evict_pages() */ + spin_unlock(&zbpg->lock); + return; + } + size = zbud_free(zh); + ASSERT_SPINLOCK(&zbpg->lock); + zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0]; + if (zh_other->size == 0) { /* was unbuddied: unlist and free */ + chunks = zbud_size_to_chunks(size) ; + spin_lock(&zbud_budlists_spinlock); + BUG_ON(list_empty(&zbud_unbuddied[chunks].list)); + list_del_init(&zbpg->bud_list); + zbud_unbuddied[chunks].count--; + spin_unlock(&zbud_budlists_spinlock); + zbud_free_raw_page(zbpg); + } else { /* was buddied: move remaining buddy to unbuddied list */ + chunks = zbud_size_to_chunks(zh_other->size) ; + spin_lock(&zbud_budlists_spinlock); + list_del_init(&zbpg->bud_list); + zcache_zbud_buddied_count--; + list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list); + zbud_unbuddied[chunks].count++; + spin_unlock(&zbud_budlists_spinlock); + spin_unlock(&zbpg->lock); + } +} + +static struct zbud_hdr *zbud_create(uint16_t client_id, uint16_t pool_id, + struct tmem_oid *oid, + uint32_t index, struct page *page, + void *cdata, unsigned size) +{ + struct zbud_hdr *zh0, *zh1, *zh = NULL; + struct zbud_page *zbpg = NULL, *ztmp; + unsigned nchunks; + char *to; + int i, found_good_buddy = 0; + + nchunks = zbud_size_to_chunks(size) ; + for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) { + spin_lock(&zbud_budlists_spinlock); + if (!list_empty(&zbud_unbuddied[i].list)) { + list_for_each_entry_safe(zbpg, ztmp, + &zbud_unbuddied[i].list, bud_list) { + if (spin_trylock(&zbpg->lock)) { + found_good_buddy = i; + goto found_unbuddied; + } + } + } + spin_unlock(&zbud_budlists_spinlock); + } + /* didn't find a good buddy, try allocating a new page */ + zbpg = zbud_alloc_raw_page(); + if (unlikely(zbpg == NULL)) + goto out; + /* ok, have a page, now compress the data before taking locks */ + spin_lock(&zbud_budlists_spinlock); + spin_lock(&zbpg->lock); + list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list); + zbud_unbuddied[nchunks].count++; + zh = &zbpg->buddy[0]; + goto init_zh; + +found_unbuddied: + ASSERT_SPINLOCK(&zbpg->lock); + zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1]; + BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0))); + if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */ + ASSERT_SENTINEL(zh0, ZBH); + zh = zh1; + } else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */ + ASSERT_SENTINEL(zh1, ZBH); + zh = zh0; + } else + BUG(); + list_del_init(&zbpg->bud_list); + zbud_unbuddied[found_good_buddy].count--; + list_add_tail(&zbpg->bud_list, &zbud_buddied_list); + zcache_zbud_buddied_count++; + +init_zh: + SET_SENTINEL(zh, ZBH); + zh->size = size; + zh->index = index; + zh->oid = *oid; + zh->pool_id = pool_id; + zh->client_id = client_id; + to = zbud_data(zh, size); + memcpy(to, cdata, size); + spin_unlock(&zbpg->lock); + spin_unlock(&zbud_budlists_spinlock); + zbud_cumul_chunk_counts[nchunks]++; + atomic_inc(&zcache_zbud_curr_zpages); + zcache_zbud_cumul_zpages++; + zcache_zbud_curr_zbytes += size; + zcache_zbud_cumul_zbytes += size; +out: + return zh; +} + +static int zbud_decompress(struct page *page, struct zbud_hdr *zh) +{ + struct zbud_page *zbpg; + unsigned budnum = zbud_budnum(zh); + size_t out_len = PAGE_SIZE; + char *to_va, *from_va; + unsigned size; + int ret = 0; + + zbpg = container_of(zh, struct zbud_page, buddy[budnum]); + spin_lock(&zbpg->lock); + if (list_empty(&zbpg->bud_list)) { + /* ignore zombie page... see zbud_evict_pages() */ + ret = -EINVAL; + goto out; + } + ASSERT_SENTINEL(zh, ZBH); + BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size()); + to_va = kmap_atomic(page); + size = zh->size; + from_va = zbud_data(zh, size); + ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len); + BUG_ON(ret != LZO_E_OK); + BUG_ON(out_len != PAGE_SIZE); + kunmap_atomic(to_va); +out: + spin_unlock(&zbpg->lock); + return ret; +} + +/* + * The following routines handle shrinking of ephemeral pages by evicting + * pages "least valuable" first. + */ + +static unsigned long zcache_evicted_raw_pages; +static unsigned long zcache_evicted_buddied_pages; +static unsigned long zcache_evicted_unbuddied_pages; + +static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, + uint16_t poolid); +static void zcache_put_pool(struct tmem_pool *pool); + +/* + * Flush and free all zbuds in a zbpg, then free the pageframe + */ +static void zbud_evict_zbpg(struct zbud_page *zbpg) +{ + struct zbud_hdr *zh; + int i, j; + uint32_t pool_id[ZBUD_MAX_BUDS], client_id[ZBUD_MAX_BUDS]; + uint32_t index[ZBUD_MAX_BUDS]; + struct tmem_oid oid[ZBUD_MAX_BUDS]; + struct tmem_pool *pool; + unsigned long flags; + + ASSERT_SPINLOCK(&zbpg->lock); + for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) { + zh = &zbpg->buddy[i]; + if (zh->size) { + client_id[j] = zh->client_id; + pool_id[j] = zh->pool_id; + oid[j] = zh->oid; + index[j] = zh->index; + j++; + } + } + spin_unlock(&zbpg->lock); + for (i = 0; i < j; i++) { + pool = zcache_get_pool_by_id(client_id[i], pool_id[i]); + BUG_ON(pool == NULL); + local_irq_save(flags); + /* these flushes should dispose of any local storage */ + tmem_flush_page(pool, &oid[i], index[i]); + local_irq_restore(flags); + zcache_put_pool(pool); + } +} + +/* + * Free nr pages. This code is funky because we want to hold the locks + * protecting various lists for as short a time as possible, and in some + * circumstances the list may change asynchronously when the list lock is + * not held. In some cases we also trylock not only to avoid waiting on a + * page in use by another cpu, but also to avoid potential deadlock due to + * lock inversion. + */ +static void zbud_evict_pages(int nr) +{ + struct zbud_page *zbpg; + int i, newly_unused_pages = 0; + + + /* now try freeing unbuddied pages, starting with least space avail */ + for (i = 0; i < MAX_CHUNK; i++) { +retry_unbud_list_i: + spin_lock_bh(&zbud_budlists_spinlock); + if (list_empty(&zbud_unbuddied[i].list)) { + spin_unlock_bh(&zbud_budlists_spinlock); + continue; + } + list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) { + if (unlikely(!spin_trylock(&zbpg->lock))) + continue; + zbud_unbuddied[i].count--; + spin_unlock(&zbud_budlists_spinlock); + zcache_evicted_unbuddied_pages++; + /* want budlists unlocked when doing zbpg eviction */ + zbud_evict_zbpg(zbpg); + newly_unused_pages++; + local_bh_enable(); + if (--nr <= 0) + goto evict_unused; + goto retry_unbud_list_i; + } + spin_unlock_bh(&zbud_budlists_spinlock); + } + + /* as a last resort, free buddied pages */ +retry_bud_list: + spin_lock_bh(&zbud_budlists_spinlock); + if (list_empty(&zbud_buddied_list)) { + spin_unlock_bh(&zbud_budlists_spinlock); + goto evict_unused; + } + list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) { + if (unlikely(!spin_trylock(&zbpg->lock))) + continue; + zcache_zbud_buddied_count--; + spin_unlock(&zbud_budlists_spinlock); + zcache_evicted_buddied_pages++; + /* want budlists unlocked when doing zbpg eviction */ + zbud_evict_zbpg(zbpg); + newly_unused_pages++; + local_bh_enable(); + if (--nr <= 0) + goto evict_unused; + goto retry_bud_list; + } + spin_unlock_bh(&zbud_budlists_spinlock); + +evict_unused: + return; +} + +static DEFINE_PER_CPU(unsigned char *, zcache_remoteputmem); + +static int zbud_remotify_zbud(struct tmem_xhandle *xh, char *data, + size_t size) +{ + struct tmem_pool *pool; + int i, remotenode, ret = -1; + unsigned char cksum, *p; + unsigned long flags; + + for (p = data, cksum = 0, i = 0; i < size; i++) + cksum += *p; + ret = ramster_remote_put(xh, data, size, true, &remotenode); + if (ret == 0) { + /* data was successfully remoted so change the local version + * to point to the remote node where it landed */ + pool = zcache_get_pool_by_id(LOCAL_CLIENT, xh->pool_id); + BUG_ON(pool == NULL); + local_irq_save(flags); + /* tmem_replace will also free up any local space */ + (void)tmem_replace(pool, &xh->oid, xh->index, + pampd_make_remote(remotenode, size, cksum)); + local_irq_restore(flags); + zcache_put_pool(pool); + ramster_eph_pages_remoted++; + ret = 0; + } else + ramster_eph_pages_remote_failed++; + return ret; +} + +static int zbud_remotify_zbpg(struct zbud_page *zbpg) +{ + struct zbud_hdr *zh1, *zh2 = NULL; + struct tmem_xhandle xh1, xh2 = { 0 }; + char *data1 = NULL, *data2 = NULL; + size_t size1 = 0, size2 = 0; + int ret = 0; + unsigned char *tmpmem = __get_cpu_var(zcache_remoteputmem); + + ASSERT_SPINLOCK(&zbpg->lock); + if (zbpg->buddy[0].size == 0) + zh1 = &zbpg->buddy[1]; + else if (zbpg->buddy[1].size == 0) + zh1 = &zbpg->buddy[0]; + else { + zh1 = &zbpg->buddy[0]; + zh2 = &zbpg->buddy[1]; + } + /* don't remotify pages that are already remotified */ + if (zh1->client_id != LOCAL_CLIENT) + zh1 = NULL; + if ((zh2 != NULL) && (zh2->client_id != LOCAL_CLIENT)) + zh2 = NULL; + + /* copy the data and metadata so can release lock */ + if (zh1 != NULL) { + xh1.client_id = zh1->client_id; + xh1.pool_id = zh1->pool_id; + xh1.oid = zh1->oid; + xh1.index = zh1->index; + size1 = zh1->size; + data1 = zbud_data(zh1, size1); + memcpy(tmpmem, zbud_data(zh1, size1), size1); + data1 = tmpmem; + tmpmem += size1; + } + if (zh2 != NULL) { + xh2.client_id = zh2->client_id; + xh2.pool_id = zh2->pool_id; + xh2.oid = zh2->oid; + xh2.index = zh2->index; + size2 = zh2->size; + memcpy(tmpmem, zbud_data(zh2, size2), size2); + data2 = tmpmem; + } + spin_unlock(&zbpg->lock); + preempt_enable(); + + /* OK, no locks held anymore, remotify one or both zbuds */ + if (zh1 != NULL) + ret = zbud_remotify_zbud(&xh1, data1, size1); + if (zh2 != NULL) + ret |= zbud_remotify_zbud(&xh2, data2, size2); + return ret; +} + +void zbud_remotify_pages(int nr) +{ + struct zbud_page *zbpg; + int i, ret; + + /* + * for now just try remotifying unbuddied pages, starting with + * least space avail + */ + for (i = 0; i < MAX_CHUNK; i++) { +retry_unbud_list_i: + preempt_disable(); /* enable in zbud_remotify_zbpg */ + spin_lock_bh(&zbud_budlists_spinlock); + if (list_empty(&zbud_unbuddied[i].list)) { + spin_unlock_bh(&zbud_budlists_spinlock); + preempt_enable(); + continue; /* next i in for loop */ + } + list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) { + if (unlikely(!spin_trylock(&zbpg->lock))) + continue; /* next list_for_each_entry */ + zbud_unbuddied[i].count--; + /* want budlists unlocked when doing zbpg remotify */ + spin_unlock_bh(&zbud_budlists_spinlock); + ret = zbud_remotify_zbpg(zbpg); + /* preemption is re-enabled in zbud_remotify_zbpg */ + if (ret == 0) { + if (--nr <= 0) + goto out; + goto retry_unbud_list_i; + } + /* if fail to remotify any page, quit */ + pr_err("TESTING zbud_remotify_pages failed on page," + " trying to re-add\n"); + spin_lock_bh(&zbud_budlists_spinlock); + spin_lock(&zbpg->lock); + list_add_tail(&zbpg->bud_list, &zbud_unbuddied[i].list); + zbud_unbuddied[i].count++; + spin_unlock(&zbpg->lock); + spin_unlock_bh(&zbud_budlists_spinlock); + pr_err("TESTING zbud_remotify_pages failed on page," + " finished re-add\n"); + goto out; + } + spin_unlock_bh(&zbud_budlists_spinlock); + preempt_enable(); + } + +next_buddied_zbpg: + preempt_disable(); /* enable in zbud_remotify_zbpg */ + spin_lock_bh(&zbud_budlists_spinlock); + if (list_empty(&zbud_buddied_list)) + goto unlock_out; + list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) { + if (unlikely(!spin_trylock(&zbpg->lock))) + continue; /* next list_for_each_entry */ + zcache_zbud_buddied_count--; + /* want budlists unlocked when doing zbpg remotify */ + spin_unlock_bh(&zbud_budlists_spinlock); + ret = zbud_remotify_zbpg(zbpg); + /* preemption is re-enabled in zbud_remotify_zbpg */ + if (ret == 0) { + if (--nr <= 0) + goto out; + goto next_buddied_zbpg; + } + /* if fail to remotify any page, quit */ + pr_err("TESTING zbud_remotify_pages failed on BUDDIED page," + " trying to re-add\n"); + spin_lock_bh(&zbud_budlists_spinlock); + spin_lock(&zbpg->lock); + list_add_tail(&zbpg->bud_list, &zbud_buddied_list); + zcache_zbud_buddied_count++; + spin_unlock(&zbpg->lock); + spin_unlock_bh(&zbud_budlists_spinlock); + pr_err("TESTING zbud_remotify_pages failed on BUDDIED page," + " finished re-add\n"); + goto out; + } +unlock_out: + spin_unlock_bh(&zbud_budlists_spinlock); + preempt_enable(); +out: + return; +} + +/* the "flush list" asynchronously collects pages to remotely flush */ +#define FLUSH_ENTIRE_OBJECT ((uint32_t)-1) +static void ramster_flnode_free(struct flushlist_node *, + struct tmem_pool *); + +static void zcache_remote_flush_page(struct flushlist_node *flnode) +{ + struct tmem_xhandle *xh; + int remotenode, ret; + + preempt_disable(); + xh = &flnode->xh; + remotenode = flnode->xh.client_id; + ret = ramster_remote_flush(xh, remotenode); + if (ret >= 0) + ramster_remote_pages_flushed++; + else + ramster_remote_page_flushes_failed++; + preempt_enable_no_resched(); + ramster_flnode_free(flnode, NULL); +} + +static void zcache_remote_flush_object(struct flushlist_node *flnode) +{ + struct tmem_xhandle *xh; + int remotenode, ret; + + preempt_disable(); + xh = &flnode->xh; + remotenode = flnode->xh.client_id; + ret = ramster_remote_flush_object(xh, remotenode); + if (ret >= 0) + ramster_remote_objects_flushed++; + else + ramster_remote_object_flushes_failed++; + preempt_enable_no_resched(); + ramster_flnode_free(flnode, NULL); +} + +static void zcache_remote_eph_put(struct zbud_hdr *zbud) +{ + /* FIXME */ +} + +static void zcache_remote_pers_put(struct zv_hdr *zv) +{ + struct tmem_xhandle xh; + uint16_t size; + bool ephemeral; + int remotenode, ret = -1; + char *data; + struct tmem_pool *pool; + unsigned long flags; + unsigned char cksum; + char *p; + int i; + unsigned char *tmpmem = __get_cpu_var(zcache_remoteputmem); + + ASSERT_SENTINEL(zv, ZVH); + BUG_ON(zv->client_id != LOCAL_CLIENT); + local_bh_disable(); + xh.client_id = zv->client_id; + xh.pool_id = zv->pool_id; + xh.oid = zv->oid; + xh.index = zv->index; + size = xv_get_object_size(zv) - sizeof(*zv); + BUG_ON(size == 0 || size > zv_max_page_size); + data = (char *)zv + sizeof(*zv); + for (p = data, cksum = 0, i = 0; i < size; i++) + cksum += *p; + memcpy(tmpmem, data, size); + data = tmpmem; + pool = zcache_get_pool_by_id(zv->client_id, zv->pool_id); + ephemeral = is_ephemeral(pool); + zcache_put_pool(pool); + /* now OK to release lock set in caller */ + spin_unlock(&zcache_rem_op_list_lock); + local_bh_enable(); + preempt_disable(); + ret = ramster_remote_put(&xh, data, size, ephemeral, &remotenode); + preempt_enable_no_resched(); + if (ret != 0) { + /* + * This is some form of a memory leak... if the remote put + * fails, there will never be another attempt to remotify + * this page. But since we've dropped the zv pointer, + * the page may have been freed or the data replaced + * so we can't just "put it back" in the remote op list. + * Even if we could, not sure where to put it in the list + * because there may be flushes that must be strictly + * ordered vs the put. So leave this as a FIXME for now. + * But count them so we know if it becomes a problem. + */ + ramster_pers_pages_remote_failed++; + goto out; + } else + atomic_inc(&ramster_remote_pers_pages); + ramster_pers_pages_remoted++; + /* + * data was successfully remoted so change the local version to + * point to the remote node where it landed + */ + local_bh_disable(); + pool = zcache_get_pool_by_id(LOCAL_CLIENT, xh.pool_id); + local_irq_save(flags); + (void)tmem_replace(pool, &xh.oid, xh.index, + pampd_make_remote(remotenode, size, cksum)); + local_irq_restore(flags); + zcache_put_pool(pool); + local_bh_enable(); +out: + return; +} + +static void zcache_do_remotify_ops(int nr) +{ + struct ramster_remotify_hdr *rem_op; + union remotify_list_node *u; + + while (1) { + if (!nr) + goto out; + spin_lock(&zcache_rem_op_list_lock); + if (list_empty(&zcache_rem_op_list)) { + spin_unlock(&zcache_rem_op_list_lock); + goto out; + } + rem_op = list_first_entry(&zcache_rem_op_list, + struct ramster_remotify_hdr, list); + list_del_init(&rem_op->list); + if (rem_op->op != RAMSTER_REMOTIFY_PERS_PUT) + spin_unlock(&zcache_rem_op_list_lock); + u = (union remotify_list_node *)rem_op; + switch (rem_op->op) { + case RAMSTER_REMOTIFY_EPH_PUT: +BUG(); + zcache_remote_eph_put((struct zbud_hdr *)rem_op); + break; + case RAMSTER_REMOTIFY_PERS_PUT: + zcache_remote_pers_put((struct zv_hdr *)rem_op); + break; + case RAMSTER_REMOTIFY_FLUSH_PAGE: + zcache_remote_flush_page((struct flushlist_node *)u); + break; + case RAMSTER_REMOTIFY_FLUSH_OBJ: + zcache_remote_flush_object((struct flushlist_node *)u); + break; + default: + BUG(); + } + } +out: + return; +} + +/* + * Communicate interface revision with userspace + */ +#include "cluster/ramster_nodemanager.h" +static unsigned long ramster_interface_revision = R2NM_API_VERSION; + +/* + * For now, just push over a few pages every few seconds to + * ensure that it basically works + */ +static struct workqueue_struct *ramster_remotify_workqueue; +static void ramster_remotify_process(struct work_struct *work); +static DECLARE_DELAYED_WORK(ramster_remotify_worker, + ramster_remotify_process); + +static void ramster_remotify_queue_delayed_work(unsigned long delay) +{ + if (!queue_delayed_work(ramster_remotify_workqueue, + &ramster_remotify_worker, delay)) + pr_err("ramster_remotify: bad workqueue\n"); +} + + +static int use_frontswap; +static int use_cleancache; +static int ramster_remote_target_nodenum = -1; +static void ramster_remotify_process(struct work_struct *work) +{ + static bool remotify_in_progress; + + BUG_ON(irqs_disabled()); + if (remotify_in_progress) + ramster_remotify_queue_delayed_work(HZ); + else if (ramster_remote_target_nodenum != -1) { + remotify_in_progress = true; +#ifdef CONFIG_CLEANCACHE + if (use_cleancache && ramster_eph_remotify_enable) + zbud_remotify_pages(5000); /* FIXME is this a good number? */ +#endif +#ifdef CONFIG_FRONTSWAP + if (use_frontswap && ramster_pers_remotify_enable) + zcache_do_remotify_ops(500); /* FIXME is this a good number? */ +#endif + remotify_in_progress = false; + ramster_remotify_queue_delayed_work(HZ); + } +} + +static void ramster_remotify_init(void) +{ + unsigned long n = 60UL; + ramster_remotify_workqueue = + create_singlethread_workqueue("ramster_remotify"); + ramster_remotify_queue_delayed_work(n * HZ); +} + + +static void zbud_init(void) +{ + int i; + + INIT_LIST_HEAD(&zbud_buddied_list); + zcache_zbud_buddied_count = 0; + for (i = 0; i < NCHUNKS; i++) { + INIT_LIST_HEAD(&zbud_unbuddied[i].list); + zbud_unbuddied[i].count = 0; + } +} + +#ifdef CONFIG_SYSFS +/* + * These sysfs routines show a nice distribution of how many zbpg's are + * currently (and have ever been placed) in each unbuddied list. It's fun + * to watch but can probably go away before final merge. + */ +static int zbud_show_unbuddied_list_counts(char *buf) +{ + int i; + char *p = buf; + + for (i = 0; i < NCHUNKS; i++) + p += sprintf(p, "%u ", zbud_unbuddied[i].count); + return p - buf; +} + +static int zbud_show_cumul_chunk_counts(char *buf) +{ + unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0; + unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0; + unsigned long total_chunks_lte_42 = 0; + char *p = buf; + + for (i = 0; i < NCHUNKS; i++) { + p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]); + chunks += zbud_cumul_chunk_counts[i]; + total_chunks += zbud_cumul_chunk_counts[i]; + sum_total_chunks += i * zbud_cumul_chunk_counts[i]; + if (i == 21) + total_chunks_lte_21 = total_chunks; + if (i == 32) + total_chunks_lte_32 = total_chunks; + if (i == 42) + total_chunks_lte_42 = total_chunks; + } + p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n", + total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42, + chunks == 0 ? 0 : sum_total_chunks / chunks); + return p - buf; +} +#endif + +/********** + * This "zv" PAM implementation combines the TLSF-based xvMalloc + * with lzo1x compression to maximize the amount of data that can + * be packed into a physical page. + * + * Zv represents a PAM page with the index and object (plus a "size" value + * necessary for decompression) immediately preceding the compressed data. + */ + +/* rudimentary policy limits */ +/* total number of persistent pages may not exceed this percentage */ +static unsigned int zv_page_count_policy_percent = 75; +/* + * byte count defining poor compression; pages with greater zsize will be + * rejected + */ +static unsigned int zv_max_zsize = (PAGE_SIZE / 8) * 7; +/* + * byte count defining poor *mean* compression; pages with greater zsize + * will be rejected until sufficient better-compressed pages are accepted + * driving the mean below this threshold + */ +static unsigned int zv_max_mean_zsize = (PAGE_SIZE / 8) * 5; + +static atomic_t zv_curr_dist_counts[NCHUNKS]; +static atomic_t zv_cumul_dist_counts[NCHUNKS]; + + +static struct zv_hdr *zv_create(struct zcache_client *cli, uint32_t pool_id, + struct tmem_oid *oid, uint32_t index, + void *cdata, unsigned clen) +{ + struct page *page; + struct zv_hdr *zv = NULL; + uint32_t offset; + int alloc_size = clen + sizeof(struct zv_hdr); + int chunks = (alloc_size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT; + int ret; + + BUG_ON(!irqs_disabled()); + BUG_ON(chunks >= NCHUNKS); + ret = xv_malloc(cli->xvpool, clen + sizeof(struct zv_hdr), + &page, &offset, ZCACHE_GFP_MASK); + if (unlikely(ret)) + goto out; + atomic_inc(&zv_curr_dist_counts[chunks]); + atomic_inc(&zv_cumul_dist_counts[chunks]); + zv = kmap_atomic(page) + offset; + zv->index = index; + zv->oid = *oid; + zv->pool_id = pool_id; + SET_SENTINEL(zv, ZVH); + INIT_LIST_HEAD(&zv->rem_op.list); + zv->client_id = get_client_id_from_client(cli); + zv->rem_op.op = RAMSTER_REMOTIFY_PERS_PUT; + if (zv->client_id == LOCAL_CLIENT) { + spin_lock(&zcache_rem_op_list_lock); + list_add_tail(&zv->rem_op.list, &zcache_rem_op_list); + spin_unlock(&zcache_rem_op_list_lock); + } + memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen); + kunmap_atomic(zv); +out: + return zv; +} + +/* similar to zv_create, but just reserve space, no data yet */ +static struct zv_hdr *zv_alloc(struct tmem_pool *pool, + struct tmem_oid *oid, uint32_t index, + unsigned clen) +{ + struct zcache_client *cli = pool->client; + struct page *page; + struct zv_hdr *zv = NULL; + uint32_t offset; + int ret; + + BUG_ON(!irqs_disabled()); + BUG_ON(!is_local_client(pool->client)); + ret = xv_malloc(cli->xvpool, clen + sizeof(struct zv_hdr), + &page, &offset, ZCACHE_GFP_MASK); + if (unlikely(ret)) + goto out; + zv = kmap_atomic(page) + offset; + SET_SENTINEL(zv, ZVH); + INIT_LIST_HEAD(&zv->rem_op.list); + zv->client_id = LOCAL_CLIENT; + zv->rem_op.op = RAMSTER_INTRANSIT_PERS; + zv->index = index; + zv->oid = *oid; + zv->pool_id = pool->pool_id; + kunmap_atomic(zv); +out: + return zv; +} + +static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv) +{ + unsigned long flags; + struct page *page; + uint32_t offset; + uint16_t size = xv_get_object_size(zv); + int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT; + + ASSERT_SENTINEL(zv, ZVH); + BUG_ON(chunks >= NCHUNKS); + atomic_dec(&zv_curr_dist_counts[chunks]); + size -= sizeof(*zv); + spin_lock(&zcache_rem_op_list_lock); + size = xv_get_object_size(zv) - sizeof(*zv); + BUG_ON(size == 0); + INVERT_SENTINEL(zv, ZVH); + if (!list_empty(&zv->rem_op.list)) + list_del_init(&zv->rem_op.list); + spin_unlock(&zcache_rem_op_list_lock); + page = virt_to_page(zv); + offset = (unsigned long)zv & ~PAGE_MASK; + local_irq_save(flags); + xv_free(xvpool, page, offset); + local_irq_restore(flags); +} + +static void zv_decompress(struct page *page, struct zv_hdr *zv) +{ + size_t clen = PAGE_SIZE; + char *to_va; + unsigned size; + int ret; + + ASSERT_SENTINEL(zv, ZVH); + size = xv_get_object_size(zv) - sizeof(*zv); + BUG_ON(size == 0); + to_va = kmap_atomic(page); + ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv), + size, to_va, &clen); + kunmap_atomic(to_va); + BUG_ON(ret != LZO_E_OK); + BUG_ON(clen != PAGE_SIZE); +} + +static void zv_copy_from_pampd(char *data, size_t *bufsize, struct zv_hdr *zv) +{ + unsigned size; + + ASSERT_SENTINEL(zv, ZVH); + size = xv_get_object_size(zv) - sizeof(*zv); + BUG_ON(size == 0 || size > zv_max_page_size); + BUG_ON(size > *bufsize); + memcpy(data, (char *)zv + sizeof(*zv), size); + *bufsize = size; +} + +static void zv_copy_to_pampd(struct zv_hdr *zv, char *data, size_t size) +{ + unsigned zv_size; + + ASSERT_SENTINEL(zv, ZVH); + zv_size = xv_get_object_size(zv) - sizeof(*zv); + BUG_ON(zv_size != size); + BUG_ON(zv_size == 0 || zv_size > zv_max_page_size); + memcpy((char *)zv + sizeof(*zv), data, size); +} + +#ifdef CONFIG_SYSFS +/* + * show a distribution of compression stats for zv pages. + */ + +static int zv_curr_dist_counts_show(char *buf) +{ + unsigned long i, n, chunks = 0, sum_total_chunks = 0; + char *p = buf; + + for (i = 0; i < NCHUNKS; i++) { + n = atomic_read(&zv_curr_dist_counts[i]); + p += sprintf(p, "%lu ", n); + chunks += n; + sum_total_chunks += i * n; + } + p += sprintf(p, "mean:%lu\n", + chunks == 0 ? 0 : sum_total_chunks / chunks); + return p - buf; +} + +static int zv_cumul_dist_counts_show(char *buf) +{ + unsigned long i, n, chunks = 0, sum_total_chunks = 0; + char *p = buf; + + for (i = 0; i < NCHUNKS; i++) { + n = atomic_read(&zv_cumul_dist_counts[i]); + p += sprintf(p, "%lu ", n); + chunks += n; + sum_total_chunks += i * n; + } + p += sprintf(p, "mean:%lu\n", + chunks == 0 ? 0 : sum_total_chunks / chunks); + return p - buf; +} + +/* + * setting zv_max_zsize via sysfs causes all persistent (e.g. swap) + * pages that don't compress to less than this value (including metadata + * overhead) to be rejected. We don't allow the value to get too close + * to PAGE_SIZE. + */ +static ssize_t zv_max_zsize_show(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf) +{ + return sprintf(buf, "%u\n", zv_max_zsize); +} + +static ssize_t zv_max_zsize_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + unsigned long val; + int err; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + err = kstrtoul(buf, 10, &val); + if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7)) + return -EINVAL; + zv_max_zsize = val; + return count; +} + +/* + * setting zv_max_mean_zsize via sysfs causes all persistent (e.g. swap) + * pages that don't compress to less than this value (including metadata + * overhead) to be rejected UNLESS the mean compression is also smaller + * than this value. In other words, we are load-balancing-by-zsize the + * accepted pages. Again, we don't allow the value to get too close + * to PAGE_SIZE. + */ +static ssize_t zv_max_mean_zsize_show(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf) +{ + return sprintf(buf, "%u\n", zv_max_mean_zsize); +} + +static ssize_t zv_max_mean_zsize_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + unsigned long val; + int err; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + err = kstrtoul(buf, 10, &val); + if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7)) + return -EINVAL; + zv_max_mean_zsize = val; + return count; +} + +/* + * setting zv_page_count_policy_percent via sysfs sets an upper bound of + * persistent (e.g. swap) pages that will be retained according to: + * (zv_page_count_policy_percent * totalram_pages) / 100) + * when that limit is reached, further puts will be rejected (until + * some pages have been flushed). Note that, due to compression, + * this number may exceed 100; it defaults to 75 and we set an + * arbitary limit of 150. A poor choice will almost certainly result + * in OOM's, so this value should only be changed prudently. + */ +static ssize_t zv_page_count_policy_percent_show(struct kobject *kobj, + struct kobj_attribute *attr, + char *buf) +{ + return sprintf(buf, "%u\n", zv_page_count_policy_percent); +} + +static ssize_t zv_page_count_policy_percent_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + unsigned long val; + int err; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + err = kstrtoul(buf, 10, &val); + if (err || (val == 0) || (val > 150)) + return -EINVAL; + zv_page_count_policy_percent = val; + return count; +} + +static struct kobj_attribute zcache_zv_max_zsize_attr = { + .attr = { .name = "zv_max_zsize", .mode = 0644 }, + .show = zv_max_zsize_show, + .store = zv_max_zsize_store, +}; + +static struct kobj_attribute zcache_zv_max_mean_zsize_attr = { + .attr = { .name = "zv_max_mean_zsize", .mode = 0644 }, + .show = zv_max_mean_zsize_show, + .store = zv_max_mean_zsize_store, +}; + +static struct kobj_attribute zcache_zv_page_count_policy_percent_attr = { + .attr = { .name = "zv_page_count_policy_percent", + .mode = 0644 }, + .show = zv_page_count_policy_percent_show, + .store = zv_page_count_policy_percent_store, +}; +#endif + +/* + * zcache core code starts here + */ + +/* useful stats not collected by cleancache or frontswap */ +static unsigned long zcache_flush_total; +static unsigned long zcache_flush_found; +static unsigned long zcache_flobj_total; +static unsigned long zcache_flobj_found; +static unsigned long zcache_failed_eph_puts; +static unsigned long zcache_nonactive_puts; +static unsigned long zcache_failed_pers_puts; + +/* + * Tmem operations assume the poolid implies the invoking client. + * Zcache only has one client (the kernel itself): LOCAL_CLIENT. + * RAMster has each client numbered by cluster node, and a KVM version + * of zcache would have one client per guest and each client might + * have a poolid==N. + */ +static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid) +{ + struct tmem_pool *pool = NULL; + struct zcache_client *cli = NULL; + + if (cli_id == LOCAL_CLIENT) + cli = &zcache_host; + else { + if (cli_id >= MAX_CLIENTS) + goto out; + cli = &zcache_clients[cli_id]; + if (cli == NULL) + goto out; + atomic_inc(&cli->refcount); + } + if (poolid < MAX_POOLS_PER_CLIENT) { + pool = cli->tmem_pools[poolid]; + if (pool != NULL) + atomic_inc(&pool->refcount); + } +out: + return pool; +} + +static void zcache_put_pool(struct tmem_pool *pool) +{ + struct zcache_client *cli = NULL; + + if (pool == NULL) + BUG(); + cli = pool->client; + atomic_dec(&pool->refcount); + atomic_dec(&cli->refcount); +} + +int zcache_new_client(uint16_t cli_id) +{ + struct zcache_client *cli = NULL; + int ret = -1; + + if (cli_id == LOCAL_CLIENT) + cli = &zcache_host; + else if ((unsigned int)cli_id < MAX_CLIENTS) + cli = &zcache_clients[cli_id]; + if (cli == NULL) + goto out; + if (cli->allocated) + goto out; + cli->allocated = 1; +#ifdef CONFIG_FRONTSWAP + cli->xvpool = xv_create_pool(); + if (cli->xvpool == NULL) + goto out; +#endif + ret = 0; +out: + return ret; +} + +/* counters for debugging */ +static unsigned long zcache_failed_get_free_pages; +static unsigned long zcache_failed_alloc; +static unsigned long zcache_put_to_flush; + +/* + * for now, used named slabs so can easily track usage; later can + * either just use kmalloc, or perhaps add a slab-like allocator + * to more carefully manage total memory utilization + */ +static struct kmem_cache *zcache_objnode_cache; +static struct kmem_cache *zcache_obj_cache; +static struct kmem_cache *ramster_flnode_cache; +static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0); +static unsigned long zcache_curr_obj_count_max; +static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0); +static unsigned long zcache_curr_objnode_count_max; + +/* + * to avoid memory allocation recursion (e.g. due to direct reclaim), we + * preload all necessary data structures so the hostops callbacks never + * actually do a malloc + */ +struct zcache_preload { + void *page; + struct tmem_obj *obj; + int nr; + struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH]; + struct flushlist_node *flnode; +}; +static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, }; + +static int zcache_do_preload(struct tmem_pool *pool) +{ + struct zcache_preload *kp; + struct tmem_objnode *objnode; + struct tmem_obj *obj; + struct flushlist_node *flnode; + void *page; + int ret = -ENOMEM; + + if (unlikely(zcache_objnode_cache == NULL)) + goto out; + if (unlikely(zcache_obj_cache == NULL)) + goto out; + preempt_disable(); + kp = &__get_cpu_var(zcache_preloads); + while (kp->nr < ARRAY_SIZE(kp->objnodes)) { + preempt_enable_no_resched(); + objnode = kmem_cache_alloc(zcache_objnode_cache, + ZCACHE_GFP_MASK); + if (unlikely(objnode == NULL)) { + zcache_failed_alloc++; + goto out; + } + preempt_disable(); + kp = &__get_cpu_var(zcache_preloads); + if (kp->nr < ARRAY_SIZE(kp->objnodes)) + kp->objnodes[kp->nr++] = objnode; + else + kmem_cache_free(zcache_objnode_cache, objnode); + } + preempt_enable_no_resched(); + obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK); + if (unlikely(obj == NULL)) { + zcache_failed_alloc++; + goto out; + } + flnode = kmem_cache_alloc(ramster_flnode_cache, ZCACHE_GFP_MASK); + if (unlikely(flnode == NULL)) { + zcache_failed_alloc++; + goto out; + } + if (is_ephemeral(pool)) { + page = (void *)__get_free_page(ZCACHE_GFP_MASK); + if (unlikely(page == NULL)) { + zcache_failed_get_free_pages++; + kmem_cache_free(zcache_obj_cache, obj); + kmem_cache_free(ramster_flnode_cache, flnode); + goto out; + } + } + preempt_disable(); + kp = &__get_cpu_var(zcache_preloads); + if (kp->obj == NULL) + kp->obj = obj; + else + kmem_cache_free(zcache_obj_cache, obj); + if (kp->flnode == NULL) + kp->flnode = flnode; + else + kmem_cache_free(ramster_flnode_cache, flnode); + if (is_ephemeral(pool)) { + if (kp->page == NULL) + kp->page = page; + else + free_page((unsigned long)page); + } + ret = 0; +out: + return ret; +} + +static int ramster_do_preload_flnode_only(struct tmem_pool *pool) +{ + struct zcache_preload *kp; + struct flushlist_node *flnode; + int ret = -ENOMEM; + + BUG_ON(!irqs_disabled()); + if (unlikely(ramster_flnode_cache == NULL)) + BUG(); + kp = &__get_cpu_var(zcache_preloads); + flnode = kmem_cache_alloc(ramster_flnode_cache, GFP_ATOMIC); + if (unlikely(flnode == NULL) && kp->flnode == NULL) + BUG(); /* FIXME handle more gracefully, but how??? */ + else if (kp->flnode == NULL) + kp->flnode = flnode; + else + kmem_cache_free(ramster_flnode_cache, flnode); + return ret; +} + +static void *zcache_get_free_page(void) +{ + struct zcache_preload *kp; + void *page; + + kp = &__get_cpu_var(zcache_preloads); + page = kp->page; + BUG_ON(page == NULL); + kp->page = NULL; + return page; +} + +static void zcache_free_page(void *p) +{ + free_page((unsigned long)p); +} + +/* + * zcache implementation for tmem host ops + */ + +static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool) +{ + struct tmem_objnode *objnode = NULL; + unsigned long count; + struct zcache_preload *kp; + + kp = &__get_cpu_var(zcache_preloads); + if (kp->nr <= 0) + goto out; + objnode = kp->objnodes[kp->nr - 1]; + BUG_ON(objnode == NULL); + kp->objnodes[kp->nr - 1] = NULL; + kp->nr--; + count = atomic_inc_return(&zcache_curr_objnode_count); + if (count > zcache_curr_objnode_count_max) + zcache_curr_objnode_count_max = count; +out: + return objnode; +} + +static void zcache_objnode_free(struct tmem_objnode *objnode, + struct tmem_pool *pool) +{ + atomic_dec(&zcache_curr_objnode_count); + BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0); + kmem_cache_free(zcache_objnode_cache, objnode); +} + +static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool) +{ + struct tmem_obj *obj = NULL; + unsigned long count; + struct zcache_preload *kp; + + kp = &__get_cpu_var(zcache_preloads); + obj = kp->obj; + BUG_ON(obj == NULL); + kp->obj = NULL; + count = atomic_inc_return(&zcache_curr_obj_count); + if (count > zcache_curr_obj_count_max) + zcache_curr_obj_count_max = count; + return obj; +} + +static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool) +{ + atomic_dec(&zcache_curr_obj_count); + BUG_ON(atomic_read(&zcache_curr_obj_count) < 0); + kmem_cache_free(zcache_obj_cache, obj); +} + +static struct flushlist_node *ramster_flnode_alloc(struct tmem_pool *pool) +{ + struct flushlist_node *flnode = NULL; + struct zcache_preload *kp; + int count; + + kp = &__get_cpu_var(zcache_preloads); + flnode = kp->flnode; + BUG_ON(flnode == NULL); + kp->flnode = NULL; + count = atomic_inc_return(&ramster_curr_flnode_count); + if (count > ramster_curr_flnode_count_max) + ramster_curr_flnode_count_max = count; + return flnode; +} + +static void ramster_flnode_free(struct flushlist_node *flnode, + struct tmem_pool *pool) +{ + atomic_dec(&ramster_curr_flnode_count); + BUG_ON(atomic_read(&ramster_curr_flnode_count) < 0); + kmem_cache_free(ramster_flnode_cache, flnode); +} + +static struct tmem_hostops zcache_hostops = { + .obj_alloc = zcache_obj_alloc, + .obj_free = zcache_obj_free, + .objnode_alloc = zcache_objnode_alloc, + .objnode_free = zcache_objnode_free, +}; + +/* + * zcache implementations for PAM page descriptor ops + */ + + +static inline void dec_and_check(atomic_t *pvar) +{ + atomic_dec(pvar); + /* later when all accounting is fixed, make this a BUG */ + WARN_ON_ONCE(atomic_read(pvar) < 0); +} + +static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0); +static unsigned long zcache_curr_eph_pampd_count_max; +static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0); +static unsigned long zcache_curr_pers_pampd_count_max; + +/* forward reference */ +static int zcache_compress(struct page *from, void **out_va, size_t *out_len); + +static int zcache_pampd_eph_create(char *data, size_t size, bool raw, + struct tmem_pool *pool, struct tmem_oid *oid, + uint32_t index, void **pampd) +{ + int ret = -1; + void *cdata = data; + size_t clen = size; + struct zcache_client *cli = pool->client; + uint16_t client_id = get_client_id_from_client(cli); + struct page *page = NULL; + unsigned long count; + + if (!raw) { + page = virt_to_page(data); + ret = zcache_compress(page, &cdata, &clen); + if (ret == 0) + goto out; + if (clen == 0 || clen > zbud_max_buddy_size()) { + zcache_compress_poor++; + goto out; + } + } + *pampd = (void *)zbud_create(client_id, pool->pool_id, oid, + index, page, cdata, clen); + if (*pampd == NULL) { + ret = -ENOMEM; + goto out; + } + ret = 0; + count = atomic_inc_return(&zcache_curr_eph_pampd_count); + if (count > zcache_curr_eph_pampd_count_max) + zcache_curr_eph_pampd_count_max = count; + if (client_id != LOCAL_CLIENT) { + count = atomic_inc_return(&ramster_foreign_eph_pampd_count); + if (count > ramster_foreign_eph_pampd_count_max) + ramster_foreign_eph_pampd_count_max = count; + } +out: + return ret; +} + +static int zcache_pampd_pers_create(char *data, size_t size, bool raw, + struct tmem_pool *pool, struct tmem_oid *oid, + uint32_t index, void **pampd) +{ + int ret = -1; + void *cdata = data; + size_t clen = size; + struct zcache_client *cli = pool->client; + struct page *page; + unsigned long count; + unsigned long zv_mean_zsize; + struct zv_hdr *zv; + long curr_pers_pampd_count; + u64 total_zsize; +#ifdef RAMSTER_TESTING + static bool pampd_neg_warned; +#endif + + curr_pers_pampd_count = atomic_read(&zcache_curr_pers_pampd_count) - + atomic_read(&ramster_remote_pers_pages); +#ifdef RAMSTER_TESTING + /* should always be positive, but warn if accounting is off */ + if (!pampd_neg_warned) { + pr_warn("ramster: bad accounting for curr_pers_pampd_count\n"); + pampd_neg_warned = true; + } +#endif + if (curr_pers_pampd_count > + (zv_page_count_policy_percent * totalram_pages) / 100) { + zcache_policy_percent_exceeded++; + goto out; + } + if (raw) + goto ok_to_create; + page = virt_to_page(data); + if (zcache_compress(page, &cdata, &clen) == 0) + goto out; + /* reject if compression is too poor */ + if (clen > zv_max_zsize) { + zcache_compress_poor++; + goto out; + } + /* reject if mean compression is too poor */ + if ((clen > zv_max_mean_zsize) && (curr_pers_pampd_count > 0)) { + total_zsize = xv_get_total_size_bytes(cli->xvpool); + zv_mean_zsize = div_u64(total_zsize, curr_pers_pampd_count); + if (zv_mean_zsize > zv_max_mean_zsize) { + zcache_mean_compress_poor++; + goto out; + } + } +ok_to_create: + *pampd = (void *)zv_create(cli, pool->pool_id, oid, index, cdata, clen); + if (*pampd == NULL) { + ret = -ENOMEM; + goto out; + } + ret = 0; + count = atomic_inc_return(&zcache_curr_pers_pampd_count); + if (count > zcache_curr_pers_pampd_count_max) + zcache_curr_pers_pampd_count_max = count; + if (is_local_client(cli)) + goto out; + zv = *(struct zv_hdr **)pampd; + count = atomic_inc_return(&ramster_foreign_pers_pampd_count); + if (count > ramster_foreign_pers_pampd_count_max) + ramster_foreign_pers_pampd_count_max = count; +out: + return ret; +} + +static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph, + struct tmem_pool *pool, struct tmem_oid *oid, + uint32_t index) +{ + void *pampd = NULL; + int ret; + bool ephemeral; + + BUG_ON(preemptible()); + ephemeral = (eph == 1) || ((eph == 0) && is_ephemeral(pool)); + if (ephemeral) + ret = zcache_pampd_eph_create(data, size, raw, pool, + oid, index, &pampd); + else + ret = zcache_pampd_pers_create(data, size, raw, pool, + oid, index, &pampd); + /* FIXME add some counters here for failed creates? */ + return pampd; +} + +/* + * fill the pageframe corresponding to the struct page with the data + * from the passed pampd + */ +static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw, + void *pampd, struct tmem_pool *pool, + struct tmem_oid *oid, uint32_t index) +{ + int ret = 0; + + BUG_ON(preemptible()); + BUG_ON(is_ephemeral(pool)); /* Fix later for shared pools? */ + BUG_ON(pampd_is_remote(pampd)); + if (raw) + zv_copy_from_pampd(data, bufsize, pampd); + else + zv_decompress(virt_to_page(data), pampd); + return ret; +} + +static int zcache_pampd_get_data_and_free(char *data, size_t *bufsize, bool raw, + void *pampd, struct tmem_pool *pool, + struct tmem_oid *oid, uint32_t index) +{ + int ret = 0; + unsigned long flags; + struct zcache_client *cli = pool->client; + + BUG_ON(preemptible()); + BUG_ON(pampd_is_remote(pampd)); + if (is_ephemeral(pool)) { + local_irq_save(flags); + if (raw) + zbud_copy_from_pampd(data, bufsize, pampd); + else + ret = zbud_decompress(virt_to_page(data), pampd); + zbud_free_and_delist((struct zbud_hdr *)pampd); + local_irq_restore(flags); + if (!is_local_client(cli)) + dec_and_check(&ramster_foreign_eph_pampd_count); + dec_and_check(&zcache_curr_eph_pampd_count); + } else { + if (is_local_client(cli)) + BUG(); + if (raw) + zv_copy_from_pampd(data, bufsize, pampd); + else + zv_decompress(virt_to_page(data), pampd); + zv_free(cli->xvpool, pampd); + if (!is_local_client(cli)) + dec_and_check(&ramster_foreign_pers_pampd_count); + dec_and_check(&zcache_curr_pers_pampd_count); + ret = 0; + } + return ret; +} + +static bool zcache_pampd_is_remote(void *pampd) +{ + return pampd_is_remote(pampd); +} + +/* + * free the pampd and remove it from any zcache lists + * pampd must no longer be pointed to from any tmem data structures! + */ +static void zcache_pampd_free(void *pampd, struct tmem_pool *pool, + struct tmem_oid *oid, uint32_t index, bool acct) +{ + struct zcache_client *cli = pool->client; + bool eph = is_ephemeral(pool); + struct zv_hdr *zv; + + BUG_ON(preemptible()); + if (pampd_is_remote(pampd)) { + WARN_ON(acct == false); + if (oid == NULL) { + /* + * a NULL oid means to ignore this pampd free + * as the remote freeing will be handled elsewhere + */ + } else if (eph) { + /* FIXME remote flush optional but probably good idea */ + /* FIXME get these working properly again */ + dec_and_check(&zcache_curr_eph_pampd_count); + } else if (pampd_is_intransit(pampd)) { + /* did a pers remote get_and_free, so just free local */ + pampd = pampd_mask_intransit_and_remote(pampd); + goto local_pers; + } else { + struct flushlist_node *flnode = + ramster_flnode_alloc(pool); + + flnode->xh.client_id = pampd_remote_node(pampd); + flnode->xh.pool_id = pool->pool_id; + flnode->xh.oid = *oid; + flnode->xh.index = index; + flnode->rem_op.op = RAMSTER_REMOTIFY_FLUSH_PAGE; + spin_lock(&zcache_rem_op_list_lock); + list_add(&flnode->rem_op.list, &zcache_rem_op_list); + spin_unlock(&zcache_rem_op_list_lock); + dec_and_check(&zcache_curr_pers_pampd_count); + dec_and_check(&ramster_remote_pers_pages); + } + } else if (eph) { + zbud_free_and_delist((struct zbud_hdr *)pampd); + if (!is_local_client(pool->client)) + dec_and_check(&ramster_foreign_eph_pampd_count); + if (acct) + /* FIXME get these working properly again */ + dec_and_check(&zcache_curr_eph_pampd_count); + } else { +local_pers: + zv = (struct zv_hdr *)pampd; + if (!is_local_client(pool->client)) + dec_and_check(&ramster_foreign_pers_pampd_count); + zv_free(cli->xvpool, zv); + if (acct) + /* FIXME get these working properly again */ + dec_and_check(&zcache_curr_pers_pampd_count); + } +} + +static void zcache_pampd_free_obj(struct tmem_pool *pool, + struct tmem_obj *obj) +{ + struct flushlist_node *flnode; + + BUG_ON(preemptible()); + if (obj->extra == NULL) + return; + BUG_ON(!pampd_is_remote(obj->extra)); + flnode = ramster_flnode_alloc(pool); + flnode->xh.client_id = pampd_remote_node(obj->extra); + flnode->xh.pool_id = pool->pool_id; + flnode->xh.oid = obj->oid; + flnode->xh.index = FLUSH_ENTIRE_OBJECT; + flnode->rem_op.op = RAMSTER_REMOTIFY_FLUSH_OBJ; + spin_lock(&zcache_rem_op_list_lock); + list_add(&flnode->rem_op.list, &zcache_rem_op_list); + spin_unlock(&zcache_rem_op_list_lock); +} + +void zcache_pampd_new_obj(struct tmem_obj *obj) +{ + obj->extra = NULL; +} + +int zcache_pampd_replace_in_obj(void *new_pampd, struct tmem_obj *obj) +{ + int ret = -1; + + if (new_pampd != NULL) { + if (obj->extra == NULL) + obj->extra = new_pampd; + /* enforce that all remote pages in an object reside + * in the same node! */ + else if (pampd_remote_node(new_pampd) != + pampd_remote_node((void *)(obj->extra))) + BUG(); + ret = 0; + } + return ret; +} + +/* + * Called by the message handler after a (still compressed) page has been + * fetched from the remote machine in response to an "is_remote" tmem_get + * or persistent tmem_localify. For a tmem_get, "extra" is the address of + * the page that is to be filled to succesfully resolve the tmem_get; for + * a (persistent) tmem_localify, "extra" is NULL (as the data is placed only + * in the local zcache). "data" points to "size" bytes of (compressed) data + * passed in the message. In the case of a persistent remote get, if + * pre-allocation was successful (see zcache_repatriate_preload), the page + * is placed into both local zcache and at "extra". + */ +int zcache_localify(int pool_id, struct tmem_oid *oidp, + uint32_t index, char *data, size_t size, + void *extra) +{ + int ret = -ENOENT; + unsigned long flags; + struct tmem_pool *pool; + bool ephemeral, delete = false; + size_t clen = PAGE_SIZE; + void *pampd, *saved_hb; + struct tmem_obj *obj; + + pool = zcache_get_pool_by_id(LOCAL_CLIENT, pool_id); + if (unlikely(pool == NULL)) + /* pool doesn't exist anymore */ + goto out; + ephemeral = is_ephemeral(pool); + local_irq_save(flags); /* FIXME: maybe only disable softirqs? */ + pampd = tmem_localify_get_pampd(pool, oidp, index, &obj, &saved_hb); + if (pampd == NULL) { + /* hmmm... must have been a flush while waiting */ +#ifdef RAMSTER_TESTING + pr_err("UNTESTED pampd==NULL in zcache_localify\n"); +#endif + if (ephemeral) + ramster_remote_eph_pages_unsucc_get++; + else + ramster_remote_pers_pages_unsucc_get++; + obj = NULL; + goto finish; + } else if (unlikely(!pampd_is_remote(pampd))) { + /* hmmm... must have been a dup put while waiting */ +#ifdef RAMSTER_TESTING + pr_err("UNTESTED dup while waiting in zcache_localify\n"); +#endif + if (ephemeral) + ramster_remote_eph_pages_unsucc_get++; + else + ramster_remote_pers_pages_unsucc_get++; + obj = NULL; + pampd = NULL; + ret = -EEXIST; + goto finish; + } else if (size == 0) { + /* no remote data, delete the local is_remote pampd */ + pampd = NULL; + if (ephemeral) + ramster_remote_eph_pages_unsucc_get++; + else + BUG(); + delete = true; + goto finish; + } + if (!ephemeral && pampd_is_intransit(pampd)) { + /* localify to zcache */ + pampd = pampd_mask_intransit_and_remote(pampd); + zv_copy_to_pampd(pampd, data, size); + } else { + pampd = NULL; + obj = NULL; + } + if (extra != NULL) { + /* decompress direct-to-memory to complete remotify */ + ret = lzo1x_decompress_safe((char *)data, size, + (char *)extra, &clen); + BUG_ON(ret != LZO_E_OK); + BUG_ON(clen != PAGE_SIZE); + } + if (ephemeral) + ramster_remote_eph_pages_succ_get++; + else + ramster_remote_pers_pages_succ_get++; + ret = 0; +finish: + tmem_localify_finish(obj, index, pampd, saved_hb, delete); + zcache_put_pool(pool); + local_irq_restore(flags); +out: + return ret; +} + +/* + * Called on a remote persistent tmem_get to attempt to preallocate + * local storage for the data contained in the remote persistent page. + * If succesfully preallocated, returns the pampd, marked as remote and + * in_transit. Else returns NULL. Note that the appropriate tmem data + * structure must be locked. + */ +static void *zcache_pampd_repatriate_preload(void *pampd, + struct tmem_pool *pool, + struct tmem_oid *oid, + uint32_t index, + bool *intransit) +{ + int clen = pampd_remote_size(pampd); + void *ret_pampd = NULL; + unsigned long flags; + + if (!pampd_is_remote(pampd)) + BUG(); + if (is_ephemeral(pool)) + BUG(); + if (pampd_is_intransit(pampd)) { + /* + * to avoid multiple allocations (and maybe a memory leak) + * don't preallocate if already in the process of being + * repatriated + */ + *intransit = true; + goto out; + } + *intransit = false; + local_irq_save(flags); + ret_pampd = (void *)zv_alloc(pool, oid, index, clen); + if (ret_pampd != NULL) { + /* + * a pampd is marked intransit if it is remote and space has + * been allocated for it locally (note, only happens for + * persistent pages, in which case the remote copy is freed) + */ + ret_pampd = pampd_mark_intransit(ret_pampd); + dec_and_check(&ramster_remote_pers_pages); + } else + ramster_pers_pages_remote_nomem++; + local_irq_restore(flags); +out: + return ret_pampd; +} + +/* + * Called on a remote tmem_get to invoke a message to fetch the page. + * Might sleep so no tmem locks can be held. "extra" is passed + * all the way through the round-trip messaging to zcache_localify. + */ +static int zcache_pampd_repatriate(void *fake_pampd, void *real_pampd, + struct tmem_pool *pool, + struct tmem_oid *oid, uint32_t index, + bool free, void *extra) +{ + struct tmem_xhandle xh; + int ret; + + if (pampd_is_intransit(real_pampd)) + /* have local space pre-reserved, so free remote copy */ + free = true; + xh = tmem_xhandle_fill(LOCAL_CLIENT, pool, oid, index); + /* unreliable request/response for now */ + ret = ramster_remote_async_get(&xh, free, + pampd_remote_node(fake_pampd), + pampd_remote_size(fake_pampd), + pampd_remote_cksum(fake_pampd), + extra); +#ifdef RAMSTER_TESTING + if (ret != 0 && ret != -ENOENT) + pr_err("TESTING zcache_pampd_repatriate returns, ret=%d\n", + ret); +#endif + return ret; +} + +static struct tmem_pamops zcache_pamops = { + .create = zcache_pampd_create, + .get_data = zcache_pampd_get_data, + .free = zcache_pampd_free, + .get_data_and_free = zcache_pampd_get_data_and_free, + .free_obj = zcache_pampd_free_obj, + .is_remote = zcache_pampd_is_remote, + .repatriate_preload = zcache_pampd_repatriate_preload, + .repatriate = zcache_pampd_repatriate, + .new_obj = zcache_pampd_new_obj, + .replace_in_obj = zcache_pampd_replace_in_obj, +}; + +/* + * zcache compression/decompression and related per-cpu stuff + */ + +#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS +#define LZO_DSTMEM_PAGE_ORDER 1 +static DEFINE_PER_CPU(unsigned char *, zcache_workmem); +static DEFINE_PER_CPU(unsigned char *, zcache_dstmem); + +static int zcache_compress(struct page *from, void **out_va, size_t *out_len) +{ + int ret = 0; + unsigned char *dmem = __get_cpu_var(zcache_dstmem); + unsigned char *wmem = __get_cpu_var(zcache_workmem); + char *from_va; + + BUG_ON(!irqs_disabled()); + if (unlikely(dmem == NULL || wmem == NULL)) + goto out; /* no buffer, so can't compress */ + from_va = kmap_atomic(from); + mb(); + ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem); + BUG_ON(ret != LZO_E_OK); + *out_va = dmem; + kunmap_atomic(from_va); + ret = 1; +out: + return ret; +} + + +static int zcache_cpu_notifier(struct notifier_block *nb, + unsigned long action, void *pcpu) +{ + int cpu = (long)pcpu; + struct zcache_preload *kp; + + switch (action) { + case CPU_UP_PREPARE: + per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages( + GFP_KERNEL | __GFP_REPEAT, + LZO_DSTMEM_PAGE_ORDER), + per_cpu(zcache_workmem, cpu) = + kzalloc(LZO1X_MEM_COMPRESS, + GFP_KERNEL | __GFP_REPEAT); + per_cpu(zcache_remoteputmem, cpu) = + kzalloc(PAGE_SIZE, GFP_KERNEL | __GFP_REPEAT); + break; + case CPU_DEAD: + case CPU_UP_CANCELED: + kfree(per_cpu(zcache_remoteputmem, cpu)); + per_cpu(zcache_remoteputmem, cpu) = NULL; + free_pages((unsigned long)per_cpu(zcache_dstmem, cpu), + LZO_DSTMEM_PAGE_ORDER); + per_cpu(zcache_dstmem, cpu) = NULL; + kfree(per_cpu(zcache_workmem, cpu)); + per_cpu(zcache_workmem, cpu) = NULL; + kp = &per_cpu(zcache_preloads, cpu); + while (kp->nr) { + kmem_cache_free(zcache_objnode_cache, + kp->objnodes[kp->nr - 1]); + kp->objnodes[kp->nr - 1] = NULL; + kp->nr--; + } + if (kp->obj) { + kmem_cache_free(zcache_obj_cache, kp->obj); + kp->obj = NULL; + } + if (kp->flnode) { + kmem_cache_free(ramster_flnode_cache, kp->flnode); + kp->flnode = NULL; + } + if (kp->page) { + free_page((unsigned long)kp->page); + kp->page = NULL; + } + break; + default: + break; + } + return NOTIFY_OK; +} + +static struct notifier_block zcache_cpu_notifier_block = { + .notifier_call = zcache_cpu_notifier +}; + +#ifdef CONFIG_SYSFS +#define ZCACHE_SYSFS_RO(_name) \ + static ssize_t zcache_##_name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ + { \ + return sprintf(buf, "%lu\n", zcache_##_name); \ + } \ + static struct kobj_attribute zcache_##_name##_attr = { \ + .attr = { .name = __stringify(_name), .mode = 0444 }, \ + .show = zcache_##_name##_show, \ + } + +#define ZCACHE_SYSFS_RO_ATOMIC(_name) \ + static ssize_t zcache_##_name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ + { \ + return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \ + } \ + static struct kobj_attribute zcache_##_name##_attr = { \ + .attr = { .name = __stringify(_name), .mode = 0444 }, \ + .show = zcache_##_name##_show, \ + } + +#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \ + static ssize_t zcache_##_name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ + { \ + return _func(buf); \ + } \ + static struct kobj_attribute zcache_##_name##_attr = { \ + .attr = { .name = __stringify(_name), .mode = 0444 }, \ + .show = zcache_##_name##_show, \ + } + +ZCACHE_SYSFS_RO(curr_obj_count_max); +ZCACHE_SYSFS_RO(curr_objnode_count_max); +ZCACHE_SYSFS_RO(flush_total); +ZCACHE_SYSFS_RO(flush_found); +ZCACHE_SYSFS_RO(flobj_total); +ZCACHE_SYSFS_RO(flobj_found); +ZCACHE_SYSFS_RO(failed_eph_puts); +ZCACHE_SYSFS_RO(nonactive_puts); +ZCACHE_SYSFS_RO(failed_pers_puts); +ZCACHE_SYSFS_RO(zbud_curr_zbytes); +ZCACHE_SYSFS_RO(zbud_cumul_zpages); +ZCACHE_SYSFS_RO(zbud_cumul_zbytes); +ZCACHE_SYSFS_RO(zbud_buddied_count); +ZCACHE_SYSFS_RO(evicted_raw_pages); +ZCACHE_SYSFS_RO(evicted_unbuddied_pages); +ZCACHE_SYSFS_RO(evicted_buddied_pages); +ZCACHE_SYSFS_RO(failed_get_free_pages); +ZCACHE_SYSFS_RO(failed_alloc); +ZCACHE_SYSFS_RO(put_to_flush); +ZCACHE_SYSFS_RO(compress_poor); +ZCACHE_SYSFS_RO(mean_compress_poor); +ZCACHE_SYSFS_RO(policy_percent_exceeded); +ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages); +ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages); +ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count); +ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count); +ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts, + zbud_show_unbuddied_list_counts); +ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts, + zbud_show_cumul_chunk_counts); +ZCACHE_SYSFS_RO_CUSTOM(zv_curr_dist_counts, + zv_curr_dist_counts_show); +ZCACHE_SYSFS_RO_CUSTOM(zv_cumul_dist_counts, + zv_cumul_dist_counts_show); + +static struct attribute *zcache_attrs[] = { + &zcache_curr_obj_count_attr.attr, + &zcache_curr_obj_count_max_attr.attr, + &zcache_curr_objnode_count_attr.attr, + &zcache_curr_objnode_count_max_attr.attr, + &zcache_flush_total_attr.attr, + &zcache_flobj_total_attr.attr, + &zcache_flush_found_attr.attr, + &zcache_flobj_found_attr.attr, + &zcache_failed_eph_puts_attr.attr, + &zcache_nonactive_puts_attr.attr, + &zcache_failed_pers_puts_attr.attr, + &zcache_policy_percent_exceeded_attr.attr, + &zcache_compress_poor_attr.attr, + &zcache_mean_compress_poor_attr.attr, + &zcache_zbud_curr_raw_pages_attr.attr, + &zcache_zbud_curr_zpages_attr.attr, + &zcache_zbud_curr_zbytes_attr.attr, + &zcache_zbud_cumul_zpages_attr.attr, + &zcache_zbud_cumul_zbytes_attr.attr, + &zcache_zbud_buddied_count_attr.attr, + &zcache_evicted_raw_pages_attr.attr, + &zcache_evicted_unbuddied_pages_attr.attr, + &zcache_evicted_buddied_pages_attr.attr, + &zcache_failed_get_free_pages_attr.attr, + &zcache_failed_alloc_attr.attr, + &zcache_put_to_flush_attr.attr, + &zcache_zbud_unbuddied_list_counts_attr.attr, + &zcache_zbud_cumul_chunk_counts_attr.attr, + &zcache_zv_curr_dist_counts_attr.attr, + &zcache_zv_cumul_dist_counts_attr.attr, + &zcache_zv_max_zsize_attr.attr, + &zcache_zv_max_mean_zsize_attr.attr, + &zcache_zv_page_count_policy_percent_attr.attr, + NULL, +}; + +static struct attribute_group zcache_attr_group = { + .attrs = zcache_attrs, + .name = "zcache", +}; + +#define RAMSTER_SYSFS_RO(_name) \ + static ssize_t ramster_##_name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ + { \ + return sprintf(buf, "%lu\n", ramster_##_name); \ + } \ + static struct kobj_attribute ramster_##_name##_attr = { \ + .attr = { .name = __stringify(_name), .mode = 0444 }, \ + .show = ramster_##_name##_show, \ + } + +#define RAMSTER_SYSFS_RW(_name) \ + static ssize_t ramster_##_name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ + { \ + return sprintf(buf, "%lu\n", ramster_##_name); \ + } \ + static ssize_t ramster_##_name##_store(struct kobject *kobj, \ + struct kobj_attribute *attr, const char *buf, size_t count) \ + { \ + int err; \ + unsigned long enable; \ + err = kstrtoul(buf, 10, &enable); \ + if (err) \ + return -EINVAL; \ + ramster_##_name = enable; \ + return count; \ + } \ + static struct kobj_attribute ramster_##_name##_attr = { \ + .attr = { .name = __stringify(_name), .mode = 0644 }, \ + .show = ramster_##_name##_show, \ + .store = ramster_##_name##_store, \ + } + +#define RAMSTER_SYSFS_RO_ATOMIC(_name) \ + static ssize_t ramster_##_name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ + { \ + return sprintf(buf, "%d\n", atomic_read(&ramster_##_name)); \ + } \ + static struct kobj_attribute ramster_##_name##_attr = { \ + .attr = { .name = __stringify(_name), .mode = 0444 }, \ + .show = ramster_##_name##_show, \ + } + +RAMSTER_SYSFS_RO(interface_revision); +RAMSTER_SYSFS_RO_ATOMIC(remote_pers_pages); +RAMSTER_SYSFS_RW(pers_remotify_enable); +RAMSTER_SYSFS_RW(eph_remotify_enable); +RAMSTER_SYSFS_RO(eph_pages_remoted); +RAMSTER_SYSFS_RO(eph_pages_remote_failed); +RAMSTER_SYSFS_RO(pers_pages_remoted); +RAMSTER_SYSFS_RO(pers_pages_remote_failed); +RAMSTER_SYSFS_RO(pers_pages_remote_nomem); +RAMSTER_SYSFS_RO(remote_pages_flushed); +RAMSTER_SYSFS_RO(remote_page_flushes_failed); +RAMSTER_SYSFS_RO(remote_objects_flushed); +RAMSTER_SYSFS_RO(remote_object_flushes_failed); +RAMSTER_SYSFS_RO(remote_eph_pages_succ_get); +RAMSTER_SYSFS_RO(remote_eph_pages_unsucc_get); +RAMSTER_SYSFS_RO(remote_pers_pages_succ_get); +RAMSTER_SYSFS_RO(remote_pers_pages_unsucc_get); +RAMSTER_SYSFS_RO_ATOMIC(foreign_eph_pampd_count); +RAMSTER_SYSFS_RO(foreign_eph_pampd_count_max); +RAMSTER_SYSFS_RO_ATOMIC(foreign_pers_pampd_count); +RAMSTER_SYSFS_RO(foreign_pers_pampd_count_max); +RAMSTER_SYSFS_RO_ATOMIC(curr_flnode_count); +RAMSTER_SYSFS_RO(curr_flnode_count_max); + +#define MANUAL_NODES 8 +static bool ramster_nodes_manual_up[MANUAL_NODES]; +static ssize_t ramster_manual_node_up_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + int i; + char *p = buf; + for (i = 0; i < MANUAL_NODES; i++) + if (ramster_nodes_manual_up[i]) + p += sprintf(p, "%d ", i); + p += sprintf(p, "\n"); + return p - buf; +} + +static ssize_t ramster_manual_node_up_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, size_t count) +{ + int err; + unsigned long node_num; + + err = kstrtoul(buf, 10, &node_num); + if (err) { + pr_err("ramster: bad strtoul?\n"); + return -EINVAL; + } + if (node_num >= MANUAL_NODES) { + pr_err("ramster: bad node_num=%lu?\n", node_num); + return -EINVAL; + } + if (ramster_nodes_manual_up[node_num]) { + pr_err("ramster: node %d already up, ignoring\n", + (int)node_num); + } else { + ramster_nodes_manual_up[node_num] = true; + r2net_hb_node_up_manual((int)node_num); + } + return count; +} + +static struct kobj_attribute ramster_manual_node_up_attr = { + .attr = { .name = "manual_node_up", .mode = 0644 }, + .show = ramster_manual_node_up_show, + .store = ramster_manual_node_up_store, +}; + +static ssize_t ramster_remote_target_nodenum_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + if (ramster_remote_target_nodenum == -1UL) + return sprintf(buf, "unset\n"); + else + return sprintf(buf, "%d\n", ramster_remote_target_nodenum); +} + +static ssize_t ramster_remote_target_nodenum_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, size_t count) +{ + int err; + unsigned long node_num; + + err = kstrtoul(buf, 10, &node_num); + if (err) { + pr_err("ramster: bad strtoul?\n"); + return -EINVAL; + } else if (node_num == -1UL) { + pr_err("ramster: disabling all remotification, " + "data may still reside on remote nodes however\n"); + return -EINVAL; + } else if (node_num >= MANUAL_NODES) { + pr_err("ramster: bad node_num=%lu?\n", node_num); + return -EINVAL; + } else if (!ramster_nodes_manual_up[node_num]) { + pr_err("ramster: node %d not up, ignoring setting " + "of remotification target\n", (int)node_num); + } else if (r2net_remote_target_node_set((int)node_num) >= 0) { + pr_info("ramster: node %d set as remotification target\n", + (int)node_num); + ramster_remote_target_nodenum = (int)node_num; + } else { + pr_err("ramster: bad num to node node_num=%d?\n", + (int)node_num); + return -EINVAL; + } + return count; +} + +static struct kobj_attribute ramster_remote_target_nodenum_attr = { + .attr = { .name = "remote_target_nodenum", .mode = 0644 }, + .show = ramster_remote_target_nodenum_show, + .store = ramster_remote_target_nodenum_store, +}; + + +static struct attribute *ramster_attrs[] = { + &ramster_interface_revision_attr.attr, + &ramster_pers_remotify_enable_attr.attr, + &ramster_eph_remotify_enable_attr.attr, + &ramster_remote_pers_pages_attr.attr, + &ramster_eph_pages_remoted_attr.attr, + &ramster_eph_pages_remote_failed_attr.attr, + &ramster_pers_pages_remoted_attr.attr, + &ramster_pers_pages_remote_failed_attr.attr, + &ramster_pers_pages_remote_nomem_attr.attr, + &ramster_remote_pages_flushed_attr.attr, + &ramster_remote_page_flushes_failed_attr.attr, + &ramster_remote_objects_flushed_attr.attr, + &ramster_remote_object_flushes_failed_attr.attr, + &ramster_remote_eph_pages_succ_get_attr.attr, + &ramster_remote_eph_pages_unsucc_get_attr.attr, + &ramster_remote_pers_pages_succ_get_attr.attr, + &ramster_remote_pers_pages_unsucc_get_attr.attr, + &ramster_foreign_eph_pampd_count_attr.attr, + &ramster_foreign_eph_pampd_count_max_attr.attr, + &ramster_foreign_pers_pampd_count_attr.attr, + &ramster_foreign_pers_pampd_count_max_attr.attr, + &ramster_curr_flnode_count_attr.attr, + &ramster_curr_flnode_count_max_attr.attr, + &ramster_manual_node_up_attr.attr, + &ramster_remote_target_nodenum_attr.attr, + NULL, +}; + +static struct attribute_group ramster_attr_group = { + .attrs = ramster_attrs, + .name = "ramster", +}; + +#endif /* CONFIG_SYSFS */ +/* + * When zcache is disabled ("frozen"), pools can be created and destroyed, + * but all puts (and thus all other operations that require memory allocation) + * must fail. If zcache is unfrozen, accepts puts, then frozen again, + * data consistency requires all puts while frozen to be converted into + * flushes. + */ +static bool zcache_freeze; + +/* + * zcache shrinker interface (only useful for ephemeral pages, so zbud only) + */ +static int shrink_zcache_memory(struct shrinker *shrink, + struct shrink_control *sc) +{ + int ret = -1; + int nr = sc->nr_to_scan; + gfp_t gfp_mask = sc->gfp_mask; + + if (nr >= 0) { + if (!(gfp_mask & __GFP_FS)) + /* does this case really need to be skipped? */ + goto out; + zbud_evict_pages(nr); + } + ret = (int)atomic_read(&zcache_zbud_curr_raw_pages); +out: + return ret; +} + +static struct shrinker zcache_shrinker = { + .shrink = shrink_zcache_memory, + .seeks = DEFAULT_SEEKS, +}; + +/* + * zcache shims between cleancache/frontswap ops and tmem + */ + +int zcache_put(int cli_id, int pool_id, struct tmem_oid *oidp, + uint32_t index, char *data, size_t size, + bool raw, int ephemeral) +{ + struct tmem_pool *pool; + int ret = -1; + + BUG_ON(!irqs_disabled()); + pool = zcache_get_pool_by_id(cli_id, pool_id); + if (unlikely(pool == NULL)) + goto out; + if (!zcache_freeze && zcache_do_preload(pool) == 0) { + /* preload does preempt_disable on success */ + ret = tmem_put(pool, oidp, index, data, size, raw, ephemeral); + if (ret < 0) { + if (is_ephemeral(pool)) + zcache_failed_eph_puts++; + else + zcache_failed_pers_puts++; + } + zcache_put_pool(pool); + preempt_enable_no_resched(); + } else { + zcache_put_to_flush++; + if (atomic_read(&pool->obj_count) > 0) + /* the put fails whether the flush succeeds or not */ + (void)tmem_flush_page(pool, oidp, index); + zcache_put_pool(pool); + } +out: + return ret; +} + +int zcache_get(int cli_id, int pool_id, struct tmem_oid *oidp, + uint32_t index, char *data, size_t *sizep, + bool raw, int get_and_free) +{ + struct tmem_pool *pool; + int ret = -1; + bool eph; + + if (!raw) { + BUG_ON(irqs_disabled()); + BUG_ON(in_softirq()); + } + pool = zcache_get_pool_by_id(cli_id, pool_id); + eph = is_ephemeral(pool); + if (likely(pool != NULL)) { + if (atomic_read(&pool->obj_count) > 0) + ret = tmem_get(pool, oidp, index, data, sizep, + raw, get_and_free); + zcache_put_pool(pool); + } + WARN_ONCE((!eph && (ret != 0)), "zcache_get fails on persistent pool, " + "bad things are very likely to happen soon\n"); +#ifdef RAMSTER_TESTING + if (ret != 0 && ret != -1 && !(ret == -EINVAL && is_ephemeral(pool))) + pr_err("TESTING zcache_get tmem_get returns ret=%d\n", ret); +#endif + if (ret == -EAGAIN) + BUG(); /* FIXME... don't need this anymore??? let's ensure */ + return ret; +} + +int zcache_flush(int cli_id, int pool_id, + struct tmem_oid *oidp, uint32_t index) +{ + struct tmem_pool *pool; + int ret = -1; + unsigned long flags; + + local_irq_save(flags); + zcache_flush_total++; + pool = zcache_get_pool_by_id(cli_id, pool_id); + ramster_do_preload_flnode_only(pool); + if (likely(pool != NULL)) { + if (atomic_read(&pool->obj_count) > 0) + ret = tmem_flush_page(pool, oidp, index); + zcache_put_pool(pool); + } + if (ret >= 0) + zcache_flush_found++; + local_irq_restore(flags); + return ret; +} + +int zcache_flush_object(int cli_id, int pool_id, struct tmem_oid *oidp) +{ + struct tmem_pool *pool; + int ret = -1; + unsigned long flags; + + local_irq_save(flags); + zcache_flobj_total++; + pool = zcache_get_pool_by_id(cli_id, pool_id); + ramster_do_preload_flnode_only(pool); + if (likely(pool != NULL)) { + if (atomic_read(&pool->obj_count) > 0) + ret = tmem_flush_object(pool, oidp); + zcache_put_pool(pool); + } + if (ret >= 0) + zcache_flobj_found++; + local_irq_restore(flags); + return ret; +} + +int zcache_client_destroy_pool(int cli_id, int pool_id) +{ + struct tmem_pool *pool = NULL; + struct zcache_client *cli = NULL; + int ret = -1; + + if (pool_id < 0) + goto out; + if (cli_id == LOCAL_CLIENT) + cli = &zcache_host; + else if ((unsigned int)cli_id < MAX_CLIENTS) + cli = &zcache_clients[cli_id]; + if (cli == NULL) + goto out; + atomic_inc(&cli->refcount); + pool = cli->tmem_pools[pool_id]; + if (pool == NULL) + goto out; + cli->tmem_pools[pool_id] = NULL; + /* wait for pool activity on other cpus to quiesce */ + while (atomic_read(&pool->refcount) != 0) + ; + atomic_dec(&cli->refcount); + local_bh_disable(); + ret = tmem_destroy_pool(pool); + local_bh_enable(); + kfree(pool); + pr_info("ramster: destroyed pool id=%d cli_id=%d\n", pool_id, cli_id); +out: + return ret; +} + +static int zcache_destroy_pool(int pool_id) +{ + return zcache_client_destroy_pool(LOCAL_CLIENT, pool_id); +} + +int zcache_new_pool(uint16_t cli_id, uint32_t flags) +{ + int poolid = -1; + struct tmem_pool *pool; + struct zcache_client *cli = NULL; + + if (cli_id == LOCAL_CLIENT) + cli = &zcache_host; + else if ((unsigned int)cli_id < MAX_CLIENTS) + cli = &zcache_clients[cli_id]; + if (cli == NULL) + goto out; + atomic_inc(&cli->refcount); + pool = kmalloc(sizeof(struct tmem_pool), GFP_ATOMIC); + if (pool == NULL) { + pr_info("ramster: pool creation failed: out of memory\n"); + goto out; + } + + for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++) + if (cli->tmem_pools[poolid] == NULL) + break; + if (poolid >= MAX_POOLS_PER_CLIENT) { + pr_info("ramster: pool creation failed: max exceeded\n"); + kfree(pool); + poolid = -1; + goto out; + } + atomic_set(&pool->refcount, 0); + pool->client = cli; + pool->pool_id = poolid; + tmem_new_pool(pool, flags); + cli->tmem_pools[poolid] = pool; + if (cli_id == LOCAL_CLIENT) + pr_info("ramster: created %s tmem pool, id=%d, local client\n", + flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral", + poolid); + else + pr_info("ramster: created %s tmem pool, id=%d, client=%d\n", + flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral", + poolid, cli_id); +out: + if (cli != NULL) + atomic_dec(&cli->refcount); + return poolid; +} + +static int zcache_local_new_pool(uint32_t flags) +{ + return zcache_new_pool(LOCAL_CLIENT, flags); +} + +int zcache_autocreate_pool(int cli_id, int pool_id, bool ephemeral) +{ + struct tmem_pool *pool; + struct zcache_client *cli = NULL; + uint32_t flags = ephemeral ? 0 : TMEM_POOL_PERSIST; + int ret = -1; + + if (cli_id == LOCAL_CLIENT) + goto out; + if (pool_id >= MAX_POOLS_PER_CLIENT) + goto out; + else if ((unsigned int)cli_id < MAX_CLIENTS) + cli = &zcache_clients[cli_id]; + if ((ephemeral && !use_cleancache) || (!ephemeral && !use_frontswap)) + BUG(); /* FIXME, handle more gracefully later */ + if (!cli->allocated) { + if (zcache_new_client(cli_id)) + BUG(); /* FIXME, handle more gracefully later */ + cli = &zcache_clients[cli_id]; + } + atomic_inc(&cli->refcount); + pool = cli->tmem_pools[pool_id]; + if (pool != NULL) { + if (pool->persistent && ephemeral) { + pr_err("zcache_autocreate_pool: type mismatch\n"); + goto out; + } + ret = 0; + goto out; + } + pool = kmalloc(sizeof(struct tmem_pool), GFP_KERNEL); + if (pool == NULL) { + pr_info("ramster: pool creation failed: out of memory\n"); + goto out; + } + atomic_set(&pool->refcount, 0); + pool->client = cli; + pool->pool_id = pool_id; + tmem_new_pool(pool, flags); + cli->tmem_pools[pool_id] = pool; + pr_info("ramster: AUTOcreated %s tmem poolid=%d, for remote client=%d\n", + flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral", + pool_id, cli_id); + ret = 0; +out: + if (cli == NULL) + BUG(); /* FIXME, handle more gracefully later */ + /* pr_err("zcache_autocreate_pool: failed\n"); */ + if (cli != NULL) + atomic_dec(&cli->refcount); + return ret; +} + +/********** + * Two kernel functionalities currently can be layered on top of tmem. + * These are "cleancache" which is used as a second-chance cache for clean + * page cache pages; and "frontswap" which is used for swap pages + * to avoid writes to disk. A generic "shim" is provided here for each + * to translate in-kernel semantics to zcache semantics. + */ + +#ifdef CONFIG_CLEANCACHE +static void zcache_cleancache_put_page(int pool_id, + struct cleancache_filekey key, + pgoff_t index, struct page *page) +{ + u32 ind = (u32) index; + struct tmem_oid oid = *(struct tmem_oid *)&key; + +#ifdef __PG_WAS_ACTIVE + if (!PageWasActive(page)) { + zcache_nonactive_puts++; + return; + } +#endif + if (likely(ind == index)) { + char *kva = page_address(page); + + (void)zcache_put(LOCAL_CLIENT, pool_id, &oid, index, + kva, PAGE_SIZE, 0, 1); + } +} + +static int zcache_cleancache_get_page(int pool_id, + struct cleancache_filekey key, + pgoff_t index, struct page *page) +{ + u32 ind = (u32) index; + struct tmem_oid oid = *(struct tmem_oid *)&key; + int ret = -1; + + preempt_disable(); + if (likely(ind == index)) { + char *kva = page_address(page); + size_t size = PAGE_SIZE; + + ret = zcache_get(LOCAL_CLIENT, pool_id, &oid, index, + kva, &size, 0, 0); +#ifdef __PG_WAS_ACTIVE + if (ret == 0) + SetPageWasActive(page); +#endif + } + preempt_enable(); + return ret; +} + +static void zcache_cleancache_flush_page(int pool_id, + struct cleancache_filekey key, + pgoff_t index) +{ + u32 ind = (u32) index; + struct tmem_oid oid = *(struct tmem_oid *)&key; + + if (likely(ind == index)) + (void)zcache_flush(LOCAL_CLIENT, pool_id, &oid, ind); +} + +static void zcache_cleancache_flush_inode(int pool_id, + struct cleancache_filekey key) +{ + struct tmem_oid oid = *(struct tmem_oid *)&key; + + (void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid); +} + +static void zcache_cleancache_flush_fs(int pool_id) +{ + if (pool_id >= 0) + (void)zcache_destroy_pool(pool_id); +} + +static int zcache_cleancache_init_fs(size_t pagesize) +{ + BUG_ON(sizeof(struct cleancache_filekey) != + sizeof(struct tmem_oid)); + BUG_ON(pagesize != PAGE_SIZE); + return zcache_local_new_pool(0); +} + +static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize) +{ + /* shared pools are unsupported and map to private */ + BUG_ON(sizeof(struct cleancache_filekey) != + sizeof(struct tmem_oid)); + BUG_ON(pagesize != PAGE_SIZE); + return zcache_local_new_pool(0); +} + +static struct cleancache_ops zcache_cleancache_ops = { + .put_page = zcache_cleancache_put_page, + .get_page = zcache_cleancache_get_page, + .invalidate_page = zcache_cleancache_flush_page, + .invalidate_inode = zcache_cleancache_flush_inode, + .invalidate_fs = zcache_cleancache_flush_fs, + .init_shared_fs = zcache_cleancache_init_shared_fs, + .init_fs = zcache_cleancache_init_fs +}; + +struct cleancache_ops zcache_cleancache_register_ops(void) +{ + struct cleancache_ops old_ops = + cleancache_register_ops(&zcache_cleancache_ops); + + return old_ops; +} +#endif + +#ifdef CONFIG_FRONTSWAP +/* a single tmem poolid is used for all frontswap "types" (swapfiles) */ +static int zcache_frontswap_poolid = -1; + +/* + * Swizzling increases objects per swaptype, increasing tmem concurrency + * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS + */ +#define SWIZ_BITS 8 +#define SWIZ_MASK ((1 << SWIZ_BITS) - 1) +#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK)) +#define iswiz(_ind) (_ind >> SWIZ_BITS) + +static inline struct tmem_oid oswiz(unsigned type, u32 ind) +{ + struct tmem_oid oid = { .oid = { 0 } }; + oid.oid[0] = _oswiz(type, ind); + return oid; +} + +static int zcache_frontswap_put_page(unsigned type, pgoff_t offset, + struct page *page) +{ + u64 ind64 = (u64)offset; + u32 ind = (u32)offset; + struct tmem_oid oid = oswiz(type, ind); + int ret = -1; + unsigned long flags; + char *kva; + + BUG_ON(!PageLocked(page)); + if (likely(ind64 == ind)) { + local_irq_save(flags); + kva = page_address(page); + ret = zcache_put(LOCAL_CLIENT, zcache_frontswap_poolid, + &oid, iswiz(ind), kva, PAGE_SIZE, 0, 0); + local_irq_restore(flags); + } + return ret; +} + +/* returns 0 if the page was successfully gotten from frontswap, -1 if + * was not present (should never happen!) */ +static int zcache_frontswap_get_page(unsigned type, pgoff_t offset, + struct page *page) +{ + u64 ind64 = (u64)offset; + u32 ind = (u32)offset; + struct tmem_oid oid = oswiz(type, ind); + int ret = -1; + + preempt_disable(); /* FIXME, remove this? */ + BUG_ON(!PageLocked(page)); + if (likely(ind64 == ind)) { + char *kva = page_address(page); + size_t size = PAGE_SIZE; + + ret = zcache_get(LOCAL_CLIENT, zcache_frontswap_poolid, + &oid, iswiz(ind), kva, &size, 0, -1); + } + preempt_enable(); /* FIXME, remove this? */ + return ret; +} + +/* flush a single page from frontswap */ +static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset) +{ + u64 ind64 = (u64)offset; + u32 ind = (u32)offset; + struct tmem_oid oid = oswiz(type, ind); + + if (likely(ind64 == ind)) + (void)zcache_flush(LOCAL_CLIENT, zcache_frontswap_poolid, + &oid, iswiz(ind)); +} + +/* flush all pages from the passed swaptype */ +static void zcache_frontswap_flush_area(unsigned type) +{ + struct tmem_oid oid; + int ind; + + for (ind = SWIZ_MASK; ind >= 0; ind--) { + oid = oswiz(type, ind); + (void)zcache_flush_object(LOCAL_CLIENT, + zcache_frontswap_poolid, &oid); + } +} + +static void zcache_frontswap_init(unsigned ignored) +{ + /* a single tmem poolid is used for all frontswap "types" (swapfiles) */ + if (zcache_frontswap_poolid < 0) + zcache_frontswap_poolid = + zcache_local_new_pool(TMEM_POOL_PERSIST); +} + +static struct frontswap_ops zcache_frontswap_ops = { + .put_page = zcache_frontswap_put_page, + .get_page = zcache_frontswap_get_page, + .invalidate_page = zcache_frontswap_flush_page, + .invalidate_area = zcache_frontswap_flush_area, + .init = zcache_frontswap_init +}; + +struct frontswap_ops zcache_frontswap_register_ops(void) +{ + struct frontswap_ops old_ops = + frontswap_register_ops(&zcache_frontswap_ops); + + return old_ops; +} +#endif + +/* + * frontswap selfshrinking + */ + +#ifdef CONFIG_FRONTSWAP +/* In HZ, controls frequency of worker invocation. */ +static unsigned int selfshrink_interval __read_mostly = 5; + +static void selfshrink_process(struct work_struct *work); +static DECLARE_DELAYED_WORK(selfshrink_worker, selfshrink_process); + +/* Enable/disable with sysfs. */ +static bool frontswap_selfshrinking __read_mostly; + +/* Enable/disable with kernel boot option. */ +static bool use_frontswap_selfshrink __initdata = true; + +/* + * The default values for the following parameters were deemed reasonable + * by experimentation, may be workload-dependent, and can all be + * adjusted via sysfs. + */ + +/* Control rate for frontswap shrinking. Higher hysteresis is slower. */ +static unsigned int frontswap_hysteresis __read_mostly = 20; + +/* + * Number of selfshrink worker invocations to wait before observing that + * frontswap selfshrinking should commence. Note that selfshrinking does + * not use a separate worker thread. + */ +static unsigned int frontswap_inertia __read_mostly = 3; + +/* Countdown to next invocation of frontswap_shrink() */ +static unsigned long frontswap_inertia_counter; + +/* + * Invoked by the selfshrink worker thread, uses current number of pages + * in frontswap (frontswap_curr_pages()), previous status, and control + * values (hysteresis and inertia) to determine if frontswap should be + * shrunk and what the new frontswap size should be. Note that + * frontswap_shrink is essentially a partial swapoff that immediately + * transfers pages from the "swap device" (frontswap) back into kernel + * RAM; despite the name, frontswap "shrinking" is very different from + * the "shrinker" interface used by the kernel MM subsystem to reclaim + * memory. + */ +static void frontswap_selfshrink(void) +{ + static unsigned long cur_frontswap_pages; + static unsigned long last_frontswap_pages; + static unsigned long tgt_frontswap_pages; + + last_frontswap_pages = cur_frontswap_pages; + cur_frontswap_pages = frontswap_curr_pages(); + if (!cur_frontswap_pages || + (cur_frontswap_pages > last_frontswap_pages)) { + frontswap_inertia_counter = frontswap_inertia; + return; + } + if (frontswap_inertia_counter && --frontswap_inertia_counter) + return; + if (cur_frontswap_pages <= frontswap_hysteresis) + tgt_frontswap_pages = 0; + else + tgt_frontswap_pages = cur_frontswap_pages - + (cur_frontswap_pages / frontswap_hysteresis); + frontswap_shrink(tgt_frontswap_pages); +} + +static int __init ramster_nofrontswap_selfshrink_setup(char *s) +{ + use_frontswap_selfshrink = false; + return 1; +} + +__setup("noselfshrink", ramster_nofrontswap_selfshrink_setup); + +static void selfshrink_process(struct work_struct *work) +{ + if (frontswap_selfshrinking && frontswap_enabled) { + frontswap_selfshrink(); + schedule_delayed_work(&selfshrink_worker, + selfshrink_interval * HZ); + } +} + +static int ramster_enabled; + +static int __init ramster_selfshrink_init(void) +{ + frontswap_selfshrinking = ramster_enabled && use_frontswap_selfshrink; + if (frontswap_selfshrinking) + pr_info("ramster: Initializing frontswap " + "selfshrinking driver.\n"); + else + return -ENODEV; + + schedule_delayed_work(&selfshrink_worker, selfshrink_interval * HZ); + + return 0; +} + +subsys_initcall(ramster_selfshrink_init); +#endif + +/* + * zcache initialization + * NOTE FOR NOW ramster MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR + * NOTHING HAPPENS! + */ + +static int ramster_enabled; + +static int __init enable_ramster(char *s) +{ + ramster_enabled = 1; + return 1; +} +__setup("ramster", enable_ramster); + +/* allow independent dynamic disabling of cleancache and frontswap */ + +static int use_cleancache = 1; + +static int __init no_cleancache(char *s) +{ + pr_info("INIT no_cleancache called\n"); + use_cleancache = 0; + return 1; +} + +/* + * FIXME: need to guarantee this gets checked before zcache_init is called + * What is the correct way to achieve this? + */ +early_param("nocleancache", no_cleancache); + +static int use_frontswap = 1; + +static int __init no_frontswap(char *s) +{ + pr_info("INIT no_frontswap called\n"); + use_frontswap = 0; + return 1; +} + +__setup("nofrontswap", no_frontswap); + +static int __init zcache_init(void) +{ + int ret = 0; + +#ifdef CONFIG_SYSFS + ret = sysfs_create_group(mm_kobj, &zcache_attr_group); + ret = sysfs_create_group(mm_kobj, &ramster_attr_group); + if (ret) { + pr_err("ramster: can't create sysfs\n"); + goto out; + } +#endif /* CONFIG_SYSFS */ +#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP) + if (ramster_enabled) { + unsigned int cpu; + + (void)r2net_register_handlers(); + tmem_register_hostops(&zcache_hostops); + tmem_register_pamops(&zcache_pamops); + ret = register_cpu_notifier(&zcache_cpu_notifier_block); + if (ret) { + pr_err("ramster: can't register cpu notifier\n"); + goto out; + } + for_each_online_cpu(cpu) { + void *pcpu = (void *)(long)cpu; + zcache_cpu_notifier(&zcache_cpu_notifier_block, + CPU_UP_PREPARE, pcpu); + } + } + zcache_objnode_cache = kmem_cache_create("zcache_objnode", + sizeof(struct tmem_objnode), 0, 0, NULL); + zcache_obj_cache = kmem_cache_create("zcache_obj", + sizeof(struct tmem_obj), 0, 0, NULL); + ramster_flnode_cache = kmem_cache_create("ramster_flnode", + sizeof(struct flushlist_node), 0, 0, NULL); +#endif +#ifdef CONFIG_CLEANCACHE + pr_info("INIT ramster_enabled=%d use_cleancache=%d\n", + ramster_enabled, use_cleancache); + if (ramster_enabled && use_cleancache) { + struct cleancache_ops old_ops; + + zbud_init(); + register_shrinker(&zcache_shrinker); + old_ops = zcache_cleancache_register_ops(); + pr_info("ramster: cleancache enabled using kernel " + "transcendent memory and compression buddies\n"); + if (old_ops.init_fs != NULL) + pr_warning("ramster: cleancache_ops overridden"); + } +#endif +#ifdef CONFIG_FRONTSWAP + pr_info("INIT ramster_enabled=%d use_frontswap=%d\n", + ramster_enabled, use_frontswap); + if (ramster_enabled && use_frontswap) { + struct frontswap_ops old_ops; + + zcache_new_client(LOCAL_CLIENT); + old_ops = zcache_frontswap_register_ops(); + pr_info("ramster: frontswap enabled using kernel " + "transcendent memory and xvmalloc\n"); + if (old_ops.init != NULL) + pr_warning("ramster: frontswap_ops overridden"); + } + if (ramster_enabled && (use_frontswap || use_cleancache)) + ramster_remotify_init(); +#endif +out: + return ret; +} + +module_init(zcache_init) |
