Now that the SLUB seems to be fixed so that it respects the requested alignment, use kmem_cache_alloc() to allocator if the block size of the buffer heads to be allocated is less than the page size. Previously, we were using 16k page on a Power system for each buffer, even when the file system was using 1k or 4k block size. Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx> --- Address the concerns found in https://bugzilla.lustre.org/show_bug.cgi?id=19184 fs/jbd2/journal.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/jbd2.h | 11 +--- 2 files changed, 134 insertions(+), 9 deletions(-) diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 3f473fa..5824353 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -39,6 +39,8 @@ #include <linux/seq_file.h> #include <linux/math64.h> #include <linux/hash.h> +#include <linux/log2.h> +#include <linux/vmalloc.h> #define CREATE_TRACE_POINTS #include <trace/events/jbd2.h> @@ -92,6 +94,7 @@ EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate); static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *); static void __journal_abort_soft (journal_t *journal, int errno); +static int jbd2_journal_create_slab(size_t slab_size); /* * Helper function used to manage commit timeouts @@ -1247,6 +1250,13 @@ int jbd2_journal_load(journal_t *journal) } } + /* + * Create a slab for this blocksize + */ + err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize)); + if (err) + return err; + /* Let the recovery code check whether it needs to recover any * data from the journal. */ if (jbd2_journal_recover(journal)) @@ -1806,6 +1816,127 @@ size_t journal_tag_bytes(journal_t *journal) } /* + * JBD memory management + * + * These functions are used to allocate block-sized chunks of memory + * used for making copies of buffer_head data. Very often it will be + * page-sized chunks of data, but sometimes it will be in + * sub-page-size chunks. (For example, 16k pages on Power systems + * with a 4k block file system.) For blocks smaller than a page, we + * use a SLAB allocator. There are slab caches for each block size, + * which are allocated at mount time, if necessary, and we only free + * (all of) the slab caches when/if the jbd2 module is unloaded. For + * this reason we don't need to a mutex to protect access to + * jbd2_slab[] allocating or releasing memory; only in + * jbd2_journal_create_slab(). + */ +#define JBD2_MAX_SLABS 8 +static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS]; +static DECLARE_MUTEX(jbd2_slab_create_sem); + +static const char *jbd2_slab_names[JBD2_MAX_SLABS] = { + "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k", + "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k" +}; + + +static void jbd2_journal_destroy_slabs(void) +{ + int i; + + for (i = 0; i < JBD2_MAX_SLABS; i++) { + if (jbd2_slab[i]) + kmem_cache_destroy(jbd2_slab[i]); + jbd2_slab[i] = NULL; + } +} + +static int jbd2_journal_create_slab(size_t size) +{ + int i = order_base_2(size) - 10; + size_t slab_size; + + if (size == PAGE_SIZE) + return 0; + + if (i >= JBD2_MAX_SLABS) + return -EINVAL; + + if (unlikely(i < 0)) + i = 0; + down(&jbd2_slab_create_sem); + if (jbd2_slab[i]) { + up(&jbd2_slab_create_sem); + return 0; /* Already created */ + } + + slab_size = 1 << (i+10); + jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size, + slab_size, 0, NULL); + up(&jbd2_slab_create_sem); + if (!jbd2_slab[i]) { + printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n"); + return -ENOMEM; + } + return 0; +} + +static struct kmem_cache *get_slab(size_t size) +{ + int i = order_base_2(size) - 10; + + BUG_ON(i >= JBD2_MAX_SLABS); + if (unlikely(i < 0)) + i = 0; + BUG_ON(jbd2_slab[i] == 0); + return jbd2_slab[i]; +} + +void *jbd2_alloc(size_t size, gfp_t flags) +{ + void *ptr; + + BUG_ON(size & (size-1)); /* Must be a power of 2 */ + + flags |= __GFP_REPEAT; + if (size == PAGE_SIZE) + ptr = (void *)__get_free_pages(flags, 0); + else if (size > PAGE_SIZE) { + int order = get_order(size); + + if (order < 3) + ptr = (void *)__get_free_pages(flags, order); + else + ptr = vmalloc(size); + } else + ptr = kmem_cache_alloc(get_slab(size), flags); + + /* Check alignment; SLUB has gotten this wrong in the past, + * and this can lead to user data corruption! */ + BUG_ON(((unsigned long) ptr) & (size-1)); + + return ptr; +} + +void jbd2_free(void *ptr, size_t size) +{ + if (size == PAGE_SIZE) { + free_pages((unsigned long)ptr, 0); + return; + } + if (size > PAGE_SIZE) { + int order = get_order(size); + + if (order < 3) + free_pages((unsigned long)ptr, order); + else + vfree(ptr); + return; + } + kmem_cache_free(get_slab(size), ptr); +}; + +/* * Journal_head storage management */ static struct kmem_cache *jbd2_journal_head_cache; @@ -2202,6 +2333,7 @@ static void jbd2_journal_destroy_caches(void) jbd2_journal_destroy_revoke_caches(); jbd2_journal_destroy_jbd2_journal_head_cache(); jbd2_journal_destroy_handle_cache(); + jbd2_journal_destroy_slabs(); } static int __init journal_init(void) diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index f1011f7..a7a8c7a 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -69,15 +69,8 @@ extern u8 jbd2_journal_enable_debug; #define jbd_debug(f, a...) /**/ #endif -static inline void *jbd2_alloc(size_t size, gfp_t flags) -{ - return (void *)__get_free_pages(flags, get_order(size)); -} - -static inline void jbd2_free(void *ptr, size_t size) -{ - free_pages((unsigned long)ptr, get_order(size)); -}; +extern void *jbd2_alloc(size_t size, gfp_t flags); +extern void jbd2_free(void *ptr, size_t size); #define JBD2_MIN_JOURNAL_BLOCKS 1024 -- 1.6.5.216.g5288a.dirty -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
