diff options
| -rw-r--r-- | include/linux/zswap.h | 6 | ||||
| -rw-r--r-- | mm/page_io.c | 6 | ||||
| -rw-r--r-- | mm/zswap.c | 119 |
3 files changed, 88 insertions, 43 deletions
diff --git a/include/linux/zswap.h b/include/linux/zswap.h index d961ead91bf1..30c193a1207e 100644 --- a/include/linux/zswap.h +++ b/include/linux/zswap.h @@ -26,7 +26,7 @@ struct zswap_lruvec_state { unsigned long zswap_total_pages(void); bool zswap_store(struct folio *folio); -bool zswap_load(struct folio *folio); +int zswap_load(struct folio *folio); void zswap_invalidate(swp_entry_t swp); int zswap_swapon(int type, unsigned long nr_pages); void zswap_swapoff(int type); @@ -44,9 +44,9 @@ static inline bool zswap_store(struct folio *folio) return false; } -static inline bool zswap_load(struct folio *folio) +static inline int zswap_load(struct folio *folio) { - return false; + return -ENOENT; } static inline void zswap_invalidate(swp_entry_t swp) {} diff --git a/mm/page_io.c b/mm/page_io.c index 9b983de351f9..4bce19df557b 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -638,11 +638,11 @@ void swap_read_folio(struct folio *folio, struct swap_iocb **plug) if (swap_read_folio_zeromap(folio)) { folio_unlock(folio); goto finish; - } else if (zswap_load(folio)) { - folio_unlock(folio); - goto finish; } + if (zswap_load(folio) != -ENOENT) + goto finish; + /* We have to read from slower devices. Increase zswap protection. */ zswap_folio_swapin(folio); diff --git a/mm/zswap.c b/mm/zswap.c index 5f0e62289444..0dcc54eab58b 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -62,6 +62,8 @@ static u64 zswap_reject_reclaim_fail; static u64 zswap_reject_compress_fail; /* Compressed page was too big for the allocator to (optimally) store */ static u64 zswap_reject_compress_poor; +/* Load or writeback failed due to decompression failure */ +static u64 zswap_decompress_fail; /* Store failed because underlying allocator could not get memory */ static u64 zswap_reject_alloc_fail; /* Store failed because the entry metadata could not be allocated (rare) */ @@ -985,11 +987,12 @@ unlock: return comp_ret == 0 && alloc_ret == 0; } -static void zswap_decompress(struct zswap_entry *entry, struct folio *folio) +static bool zswap_decompress(struct zswap_entry *entry, struct folio *folio) { struct zpool *zpool = entry->pool->zpool; struct scatterlist input, output; struct crypto_acomp_ctx *acomp_ctx; + int decomp_ret, dlen; u8 *src, *obj; acomp_ctx = acomp_ctx_get_cpu_lock(entry->pool); @@ -1012,11 +1015,21 @@ static void zswap_decompress(struct zswap_entry *entry, struct folio *folio) sg_init_table(&output, 1); sg_set_folio(&output, folio, PAGE_SIZE, 0); acomp_request_set_params(acomp_ctx->req, &input, &output, entry->length, PAGE_SIZE); - BUG_ON(crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &acomp_ctx->wait)); - BUG_ON(acomp_ctx->req->dlen != PAGE_SIZE); + decomp_ret = crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &acomp_ctx->wait); + dlen = acomp_ctx->req->dlen; zpool_obj_read_end(zpool, entry->handle, obj); acomp_ctx_put_unlock(acomp_ctx); + + if (!decomp_ret && dlen == PAGE_SIZE) + return true; + + zswap_decompress_fail++; + pr_alert_ratelimited("Decompression error from zswap (%d:%lu %s %u->%d)\n", + swp_type(entry->swpentry), + swp_offset(entry->swpentry), + entry->pool->tfm_name, entry->length, dlen); + return false; } /********************************* @@ -1046,6 +1059,7 @@ static int zswap_writeback_entry(struct zswap_entry *entry, struct writeback_control wbc = { .sync_mode = WB_SYNC_NONE, }; + int ret = 0; /* try to allocate swap cache folio */ si = get_swap_device(swpentry); @@ -1067,8 +1081,8 @@ static int zswap_writeback_entry(struct zswap_entry *entry, * and freed when invalidated by the concurrent shrinker anyway. */ if (!folio_was_allocated) { - folio_put(folio); - return -EEXIST; + ret = -EEXIST; + goto out; } /* @@ -1081,14 +1095,17 @@ static int zswap_writeback_entry(struct zswap_entry *entry, * be dereferenced. */ tree = swap_zswap_tree(swpentry); - if (entry != xa_cmpxchg(tree, offset, entry, NULL, GFP_KERNEL)) { - delete_from_swap_cache(folio); - folio_unlock(folio); - folio_put(folio); - return -ENOMEM; + if (entry != xa_load(tree, offset)) { + ret = -ENOMEM; + goto out; } - zswap_decompress(entry, folio); + if (!zswap_decompress(entry, folio)) { + ret = -EIO; + goto out; + } + + xa_erase(tree, offset); count_vm_event(ZSWPWB); if (entry->objcg) @@ -1104,9 +1121,14 @@ static int zswap_writeback_entry(struct zswap_entry *entry, /* start writeback */ __swap_writepage(folio, &wbc); - folio_put(folio); - return 0; +out: + if (ret && ret != -EEXIST) { + delete_from_swap_cache(folio); + folio_unlock(folio); + } + folio_put(folio); + return ret; } /********************************* @@ -1606,7 +1628,27 @@ check_old: return ret; } -bool zswap_load(struct folio *folio) +/** + * zswap_load() - load a folio from zswap + * @folio: folio to load + * + * Return: 0 on success, with the folio unlocked and marked up-to-date, or one + * of the following error codes: + * + * -EIO: if the swapped out content was in zswap, but could not be loaded + * into the page due to a decompression failure. The folio is unlocked, but + * NOT marked up-to-date, so that an IO error is emitted (e.g. do_swap_page() + * will SIGBUS). + * + * -EINVAL: if the swapped out content was in zswap, but the page belongs + * to a large folio, which is not supported by zswap. The folio is unlocked, + * but NOT marked up-to-date, so that an IO error is emitted (e.g. + * do_swap_page() will SIGBUS). + * + * -ENOENT: if the swapped out content was not in zswap. The folio remains + * locked on return. + */ +int zswap_load(struct folio *folio) { swp_entry_t swp = folio->swap; pgoff_t offset = swp_offset(swp); @@ -1617,18 +1659,32 @@ bool zswap_load(struct folio *folio) VM_WARN_ON_ONCE(!folio_test_locked(folio)); if (zswap_never_enabled()) - return false; + return -ENOENT; /* * Large folios should not be swapped in while zswap is being used, as * they are not properly handled. Zswap does not properly load large * folios, and a large folio may only be partially in zswap. - * - * Return true without marking the folio uptodate so that an IO error is - * emitted (e.g. do_swap_page() will sigbus). */ - if (WARN_ON_ONCE(folio_test_large(folio))) - return true; + if (WARN_ON_ONCE(folio_test_large(folio))) { + folio_unlock(folio); + return -EINVAL; + } + + entry = xa_load(tree, offset); + if (!entry) + return -ENOENT; + + if (!zswap_decompress(entry, folio)) { + folio_unlock(folio); + return -EIO; + } + + folio_mark_uptodate(folio); + + count_vm_event(ZSWPIN); + if (entry->objcg) + count_objcg_events(entry->objcg, ZSWPIN, 1); /* * When reading into the swapcache, invalidate our entry. The @@ -1642,27 +1698,14 @@ bool zswap_load(struct folio *folio) * files, which reads into a private page and may free it if * the fault fails. We remain the primary owner of the entry.) */ - if (swapcache) - entry = xa_erase(tree, offset); - else - entry = xa_load(tree, offset); - - if (!entry) - return false; - - zswap_decompress(entry, folio); - - count_vm_event(ZSWPIN); - if (entry->objcg) - count_objcg_events(entry->objcg, ZSWPIN, 1); - if (swapcache) { - zswap_entry_free(entry); folio_mark_dirty(folio); + xa_erase(tree, offset); + zswap_entry_free(entry); } - folio_mark_uptodate(folio); - return true; + folio_unlock(folio); + return 0; } void zswap_invalidate(swp_entry_t swp) @@ -1757,6 +1800,8 @@ static int zswap_debugfs_init(void) zswap_debugfs_root, &zswap_reject_compress_fail); debugfs_create_u64("reject_compress_poor", 0444, zswap_debugfs_root, &zswap_reject_compress_poor); + debugfs_create_u64("decompress_fail", 0444, + zswap_debugfs_root, &zswap_decompress_fail); debugfs_create_u64("written_back_pages", 0444, zswap_debugfs_root, &zswap_written_back_pages); debugfs_create_file("pool_total_size", 0444, |