From 3477d204658733aa3a87d3ae03b0327c1e599517 Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Wed, 19 Nov 2008 11:53:15 +0200 Subject: [PATCH] UBIFS: pre-allocate bulk-read buffer To avoid memory allocation failure during bulk-read, pre-allocate a bulk-read buffer, so that if there is only one bulk-reader at a time, it would just use the pre-allocated buffer and would not do any memory allocation. However, if there are more than 1 bulk- reader, then only one reader would use the pre-allocated buffer, while the other reader would allocate the buffer for itself. Signed-off-by: Artem Bityutskiy --- fs/ubifs/file.c | 31 ++++++++++++++++++-------- fs/ubifs/super.c | 57 ++++++++++++++++++++++++++++++++++++++++-------- fs/ubifs/ubifs.h | 6 +++++ 3 files changed, 76 insertions(+), 18 deletions(-) diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c index 0c5c27d63f6e..2624411d9758 100644 --- a/fs/ubifs/file.c +++ b/fs/ubifs/file.c @@ -811,15 +811,15 @@ static int ubifs_bulk_read(struct page *page) struct ubifs_inode *ui = ubifs_inode(inode); pgoff_t index = page->index, last_page_read = ui->last_page_read; struct bu_info *bu; - int err = 0; + int err = 0, allocated = 0; ui->last_page_read = index; if (!c->bulk_read) return 0; /* - * Bulk-read is protected by ui_mutex, but it is an optimization, so - * don't bother if we cannot lock the mutex. + * Bulk-read is protected by @ui->ui_mutex, but it is an optimization, + * so don't bother if we cannot lock the mutex. */ if (!mutex_trylock(&ui->ui_mutex)) return 0; @@ -840,17 +840,30 @@ static int ubifs_bulk_read(struct page *page) ui->bulk_read = 1; } - bu = kmalloc(sizeof(struct bu_info), GFP_NOFS | __GFP_NOWARN); - if (!bu) - return 0; + /* + * If possible, try to use pre-allocated bulk-read information, which + * is protected by @c->bu_mutex. + */ + if (mutex_trylock(&c->bu_mutex)) + bu = &c->bu; + else { + bu = kmalloc(sizeof(struct bu_info), GFP_NOFS | __GFP_NOWARN); + if (!bu) + goto out_unlock; + + bu->buf = NULL; + allocated = 1; + } - bu->buf = NULL; bu->buf_len = c->max_bu_buf_len; data_key_init(c, &bu->key, inode->i_ino, page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT); - err = ubifs_do_bulk_read(c, bu, page); - kfree(bu); + + if (!allocated) + mutex_unlock(&c->bu_mutex); + else + kfree(bu); out_unlock: mutex_unlock(&ui->ui_mutex); diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c index 1d511569c035..d80b2aef42b6 100644 --- a/fs/ubifs/super.c +++ b/fs/ubifs/super.c @@ -572,14 +572,6 @@ static int init_constants_early(struct ubifs_info *c) c->max_bu_buf_len = UBIFS_MAX_BULK_READ * UBIFS_MAX_DATA_NODE_SZ; if (c->max_bu_buf_len > c->leb_size) c->max_bu_buf_len = c->leb_size; - if (c->max_bu_buf_len > UBIFS_KMALLOC_OK) { - /* Check if we can kmalloc that much */ - void *try = kmalloc(c->max_bu_buf_len, - GFP_KERNEL | __GFP_NOWARN); - kfree(try); - if (!try) - c->max_bu_buf_len = UBIFS_KMALLOC_OK; - } return 0; } @@ -998,6 +990,34 @@ static void destroy_journal(struct ubifs_info *c) free_buds(c); } +/** + * bu_init - initialize bulk-read information. + * @c: UBIFS file-system description object + */ +static void bu_init(struct ubifs_info *c) +{ + ubifs_assert(c->bulk_read == 1); + + if (c->bu.buf) + return; /* Already initialized */ + +again: + c->bu.buf = kmalloc(c->max_bu_buf_len, GFP_KERNEL | __GFP_NOWARN); + if (!c->bu.buf) { + if (c->max_bu_buf_len > UBIFS_KMALLOC_OK) { + c->max_bu_buf_len = UBIFS_KMALLOC_OK; + goto again; + } + + /* Just disable bulk-read */ + ubifs_warn("Cannot allocate %d bytes of memory for bulk-read, " + "disabling it", c->max_bu_buf_len); + c->mount_opts.bulk_read = 1; + c->bulk_read = 0; + return; + } +} + /** * mount_ubifs - mount UBIFS file-system. * @c: UBIFS file-system description object @@ -1066,6 +1086,13 @@ static int mount_ubifs(struct ubifs_info *c) goto out_free; } + if (c->bulk_read == 1) + bu_init(c); + + /* + * We have to check all CRCs, even for data nodes, when we mount the FS + * (specifically, when we are replaying). + */ c->always_chk_crc = 1; err = ubifs_read_superblock(c); @@ -1296,6 +1323,7 @@ static int mount_ubifs(struct ubifs_info *c) out_dereg: dbg_failure_mode_deregistration(c); out_free: + kfree(c->bu.buf); vfree(c->ileb_buf); vfree(c->sbuf); kfree(c->bottom_up_buf); @@ -1332,10 +1360,11 @@ static void ubifs_umount(struct ubifs_info *c) kfree(c->cbuf); kfree(c->rcvrd_mst_node); kfree(c->mst_node); + kfree(c->bu.buf); + vfree(c->ileb_buf); vfree(c->sbuf); kfree(c->bottom_up_buf); UBIFS_DBG(vfree(c->dbg_buf)); - vfree(c->ileb_buf); dbg_failure_mode_deregistration(c); } @@ -1633,6 +1662,7 @@ static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data) ubifs_err("invalid or unknown remount parameter"); return err; } + if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) { err = ubifs_remount_rw(c); if (err) @@ -1640,6 +1670,14 @@ static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data) } else if (!(sb->s_flags & MS_RDONLY) && (*flags & MS_RDONLY)) ubifs_remount_ro(c); + if (c->bulk_read == 1) + bu_init(c); + else { + dbg_gen("disable bulk-read"); + kfree(c->bu.buf); + c->bu.buf = NULL; + } + return 0; } @@ -1730,6 +1768,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent) mutex_init(&c->log_mutex); mutex_init(&c->mst_mutex); mutex_init(&c->umount_mutex); + mutex_init(&c->bu_mutex); init_waitqueue_head(&c->cmt_wq); c->buds = RB_ROOT; c->old_idx = RB_ROOT; diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h index 870b5c479e95..46b172560a06 100644 --- a/fs/ubifs/ubifs.h +++ b/fs/ubifs/ubifs.h @@ -969,7 +969,10 @@ struct ubifs_mount_opts { * @mst_node: master node * @mst_offs: offset of valid master node * @mst_mutex: protects the master node area, @mst_node, and @mst_offs + * * @max_bu_buf_len: maximum bulk-read buffer length + * @bu_mutex: protects the pre-allocated bulk-read buffer and @c->bu + * @bu: pre-allocated bulk-read information * * @log_lebs: number of logical eraseblocks in the log * @log_bytes: log size in bytes @@ -1217,7 +1220,10 @@ struct ubifs_info { struct ubifs_mst_node *mst_node; int mst_offs; struct mutex mst_mutex; + int max_bu_buf_len; + struct mutex bu_mutex; + struct bu_info bu; int log_lebs; long long log_bytes; -- GitLab