lib/commands/toolcontext.c | 2 ++ lib/config/config_settings.h | 8 ++++++++ lib/config/defaults.h | 2 ++ lib/label/label.c | 40 ++++++++++++++++++++-------------------- lib/misc/lvm-globals.c | 10 ++++++++++ lib/misc/lvm-globals.h | 3 +++ 6 files changed, 45 insertions(+), 20 deletions(-) diff --git a/lib/commands/toolcontext.c b/lib/commands/toolcontext.c index 4d3f744..95b2317 100644 --- a/lib/commands/toolcontext.c +++ b/lib/commands/toolcontext.c @@ -693,6 +693,8 @@ static int _process_config(struct cmd_context *cmd) if (!_init_system_id(cmd)) return_0; + init_io_memory_size(find_config_tree_int(cmd, global_io_memory_size_CFG, NULL)); + return 1; } diff --git a/lib/config/config_settings.h b/lib/config/config_settings.h index 2de3fd4..c3e9600 100644 --- a/lib/config/config_settings.h +++ b/lib/config/config_settings.h @@ -1138,6 +1138,14 @@ cfg(global_notify_dbus_CFG, "notify_dbus", global_CFG_SECTION, 0, CFG_TYPE_BOOL, "When enabled, an LVM command that changes PVs, changes VG metadata,\n" "or changes the activation state of an LV will send a notification.\n") +cfg(global_io_memory_size_CFG, "io_memory_size", global_CFG_SECTION, CFG_DEFAULT_COMMENTED, CFG_TYPE_INT, DEFAULT_IO_MEMORY_SIZE_KB, vsn(2, 2, 184), NULL, 0, NULL, + "The amount of memory in KiB that LVM allocates to perform disk io.\n" + "LVM performance may benefit from more io memory when there are many\n" + "disks or VG metadata is large. Increasing this size may be necessary\n" + "when a single copy of VG metadata is larger than the current setting.\n" + "This value should usually not be decreased from the default; setting\n" + "it too low can result in lvm failing to read VGs.\n") + cfg(activation_udev_sync_CFG, "udev_sync", activation_CFG_SECTION, 0, CFG_TYPE_BOOL, DEFAULT_UDEV_SYNC, vsn(2, 2, 51), NULL, 0, NULL, "Use udev notifications to synchronize udev and LVM.\n" "The --nodevsync option overrides this setting.\n" diff --git a/lib/config/defaults.h b/lib/config/defaults.h index b3e6c34..690bf56 100644 --- a/lib/config/defaults.h +++ b/lib/config/defaults.h @@ -267,4 +267,6 @@ #define DEFAULT_THIN_POOL_AUTOEXTEND_THRESHOLD 100 #define DEFAULT_THIN_POOL_AUTOEXTEND_PERCENT 20 +#define DEFAULT_IO_MEMORY_SIZE_KB 4096 + #endif /* _LVM_DEFAULTS_H */ diff --git a/lib/label/label.c b/lib/label/label.c index 03726d0..4ec7d9b 100644 --- a/lib/label/label.c +++ b/lib/label/label.c @@ -772,33 +772,33 @@ out: } /* - * How many blocks to set up in bcache? Is 1024 a good max? + * num_devs is the number of devices the caller is going to scan. + * When 0 the caller doesn't know, and we use the default cache size. + * When non-zero, allocate at least num_devs bcache blocks. + * num_devs doesn't really tell us how many bcache blocks we'll use + * because it includes lvm devs and non-lvm devs, and each lvm dev + * will often use a number of bcache blocks. * - * Currently, we tell bcache to set up N blocks where N - * is the number of devices that are going to be scanned. - * Reasons why this number may not be be a good choice: - * - * - there may be a lot of non-lvm devices, which - * would make this number larger than necessary - * - * - each lvm device may use more than one cache - * block if the metadata is large enough or it - * uses more than one metadata area, which - * would make this number smaller than it - * should be for the best performance. - * - * This is even more tricky to estimate when lvmetad - * is used, because it's hard to predict how many - * devs might need to be scanned when using lvmetad. - * This currently just sets up bcache with MIN blocks. + * We don't know ahead of time if we will find some VG metadata + * that is larger than the total size of the bcache, which would + * prevent us from reading/writing the VG since we do not dynamically + * increase the bcache size when we find it's too small. In these + * cases the user would need to set io_memory_size to be larger + * than the max VG metadata size (lvm does not impose any limit on + * the metadata size.) */ -#define MIN_BCACHE_BLOCKS 32 +#define MIN_BCACHE_BLOCKS 32 /* 4MB, currently matches DEFAULT_IO_MEMORY_SIZE_KB */ #define MAX_BCACHE_BLOCKS 1024 -static int _setup_bcache(int cache_blocks) +static int _setup_bcache(int num_devs) { struct io_engine *ioe = NULL; + int iomem_kb = io_memory_size(); + int block_size_kb = (BCACHE_BLOCK_SIZE_IN_SECTORS * 512) / 1024; + int cache_blocks; + + cache_blocks = iomem_kb / block_size_kb; if (cache_blocks < MIN_BCACHE_BLOCKS) cache_blocks = MIN_BCACHE_BLOCKS; diff --git a/lib/misc/lvm-globals.c b/lib/misc/lvm-globals.c index 82c5706..3bd5cac 100644 --- a/lib/misc/lvm-globals.c +++ b/lib/misc/lvm-globals.c @@ -54,6 +54,7 @@ static char _sysfs_dir_path[PATH_MAX] = ""; static int _dev_disable_after_error_count = DEFAULT_DISABLE_AFTER_ERROR_COUNT; static uint64_t _pv_min_size = (DEFAULT_PV_MIN_SIZE_KB * 1024L >> SECTOR_SHIFT); static const char *_unknown_device_name = DEFAULT_UNKNOWN_DEVICE_NAME; +static int _io_memory_size_kb = DEFAULT_IO_MEMORY_SIZE_KB; void init_verbose(int level) { @@ -387,3 +388,12 @@ void init_unknown_device_name(const char *name) _unknown_device_name = name; } +int io_memory_size(void) +{ + return _io_memory_size_kb; +} + +void init_io_memory_size(int val) +{ + _io_memory_size_kb = val; +} diff --git a/lib/misc/lvm-globals.h b/lib/misc/lvm-globals.h index f985cfa..3007cc5 100644 --- a/lib/misc/lvm-globals.h +++ b/lib/misc/lvm-globals.h @@ -53,6 +53,7 @@ void init_pv_min_size(uint64_t sectors); void init_activation_checks(int checks); void init_retry_deactivation(int retry); void init_unknown_device_name(const char *name); +void init_io_memory_size(int val); void set_cmd_name(const char *cmd_name); const char *get_cmd_name(void); @@ -86,6 +87,7 @@ uint64_t pv_min_size(void); int activation_checks(void); int retry_deactivation(void); const char *unknown_device_name(void); +int io_memory_size(void); #define DMEVENTD_MONITOR_IGNORE -1 int dmeventd_monitor_mode(void); @@ -93,4 +95,5 @@ int dmeventd_monitor_mode(void); #define NO_DEV_ERROR_COUNT_LIMIT 0 int dev_disable_after_error_count(void); + #endif