From: Mike Snitzer Date: Fri, 20 Aug 2010 20:59:05 +0000 (+0000) Subject: Update heuristic used for default and detected data alignment. X-Git-Tag: v2_02_91~1570 X-Git-Url: https://sourceware.org/git/?a=commitdiff_plain;h=4efb1d9cbbd8d38e2462cd76b9bb1b247e5b549c;p=lvm2.git Update heuristic used for default and detected data alignment. Add "devices/default_data_alignment" to lvm.conf to control the internal default that LVM2 uses: 0==64k, 1==1MB, 2==2MB, etc. If --dataalignment (or lvm.conf's "devices/data_alignment") is specified then it is always used to align the start of the data area. This means the md_chunk_alignment and data_alignment_detection are disabled if set. (Same now applies to pvcreate --dataalignmentoffset, the specified value will be used instead of the result from data_alignment_offset_detection) set_pe_align() still looks to use the determined default alignment (based on lvm.conf's default_data_alignment) if the default is a multiple of the MD or topology detected values. --- diff --git a/WHATS_NEW b/WHATS_NEW index 8a1085ed3..48145495b 100644 --- a/WHATS_NEW +++ b/WHATS_NEW @@ -1,5 +1,7 @@ Version 2.02.74 - ================================== + Update heuristic used for default and detected data alignment. + Add "devices/default_data_alignment" to lvm.conf. Add implmentation for simple numeric 'get' property functions. Define GET_NUM_PROPERTY_FN macro to simplify numeric property 'get' function Add properties.[ch] to lib/report, defined based on columns.h. diff --git a/doc/example.conf.in b/doc/example.conf.in index 7edae7153..6c75f8c98 100644 --- a/doc/example.conf.in +++ b/doc/example.conf.in @@ -98,6 +98,11 @@ devices { # 1 enables; 0 disables. md_chunk_alignment = 1 + # Default alignment of the start of a data area in MB. If set to 0, + # a small value of 64KB will be used, which was the default until + # LVM2 version 2.02.73. Set to 1 for 1MiB, 2 for 2MiB, etc. + default_data_alignment = 1 + # By default, the start of a PV's data area will be a multiple of # the 'minimum_io_size' or 'optimal_io_size' exposed in sysfs. # - minimum_io_size - the smallest request the device can perform @@ -111,9 +116,9 @@ devices { data_alignment_detection = 1 # Alignment (in KB) of start of data area when creating a new PV. - # If a PV is placed directly upon an md device and md_chunk_alignment or - # data_alignment_detection is enabled this parameter is ignored. - # Set to 0 for the default alignment of 1MB or page size, if larger. + # md_chunk_alignment and data_alignment_detection are disabled if set. + # Set to 0 for the default alignment (see: data_alignment_default) + # or page size, if larger. data_alignment = 0 # By default, the start of the PV's aligned data area will be shifted by @@ -122,6 +127,7 @@ devices { # windows partitioning will have an alignment_offset of 3584 bytes # (sector 7 is the lowest aligned logical block, the 4KB sectors start # at LBA -1, and consequently sector 63 is aligned on a 4KB boundary). + # But note that pvcreate --dataalignmentoffset will skip this detection. # 1 enables; 0 disables. data_alignment_offset_detection = 1 diff --git a/lib/config/defaults.h b/lib/config/defaults.h index b6308f454..d9c9e3b28 100644 --- a/lib/config/defaults.h +++ b/lib/config/defaults.h @@ -17,6 +17,7 @@ #define _LVM_DEFAULTS_H #define DEFAULT_PE_ALIGN 2048 +#define DEFAULT_PE_ALIGN_OLD 128 #define DEFAULT_ARCHIVE_ENABLED 1 #define DEFAULT_BACKUP_ENABLED 1 @@ -33,6 +34,7 @@ #define DEFAULT_MD_CHUNK_ALIGNMENT 1 #define DEFAULT_IGNORE_SUSPENDED_DEVICES 1 #define DEFAULT_REQUIRE_RESTOREFILE_WITH_UUID 1 +#define DEFAULT_DATA_ALIGNMENT 1 #define DEFAULT_DATA_ALIGNMENT_OFFSET_DETECTION 1 #define DEFAULT_DATA_ALIGNMENT_DETECTION 1 diff --git a/lib/format_text/format-text.c b/lib/format_text/format-text.c index c8cf89a13..db5af2a1a 100644 --- a/lib/format_text/format-text.c +++ b/lib/format_text/format-text.c @@ -1861,16 +1861,20 @@ static int _text_pv_setup(const struct format_type *fmt, 0) * 2; if (set_pe_align(pv, data_alignment) != data_alignment && - data_alignment) - log_warn("WARNING: %s: Overriding data alignment to " - "%lu sectors (requested %lu sectors)", - pv_dev_name(pv), pv->pe_align, data_alignment); + data_alignment) { + log_error("%s: invalid data alignment of " + "%lu sectors (requested %lu sectors)", + pv_dev_name(pv), pv->pe_align, data_alignment); + return 0; + } if (set_pe_align_offset(pv, data_alignment_offset) != data_alignment_offset && - data_alignment_offset) - log_warn("WARNING: %s: Overriding data alignment offset to " - "%lu sectors (requested %lu sectors)", - pv_dev_name(pv), pv->pe_align_offset, data_alignment_offset); + data_alignment_offset) { + log_error("%s: invalid data alignment offset of " + "%lu sectors (requested %lu sectors)", + pv_dev_name(pv), pv->pe_align_offset, data_alignment_offset); + return 0; + } if (pv->pe_align < pv->pe_align_offset) { log_error("%s: pe_align (%lu sectors) must not be less " diff --git a/lib/metadata/metadata.c b/lib/metadata/metadata.c index 2a3d03695..d14c33c74 100644 --- a/lib/metadata/metadata.c +++ b/lib/metadata/metadata.c @@ -62,23 +62,38 @@ static uint32_t _vg_bad_status_bits(const struct volume_group *vg, const char _really_init[] = "Really INITIALIZE physical volume \"%s\" of volume group \"%s\" [y/n]? "; -static int _alignment_overrides_default(unsigned long data_alignment) +static int _alignment_overrides_default(unsigned long data_alignment, + unsigned long default_pe_align) { - return data_alignment && (DEFAULT_PE_ALIGN % data_alignment); + return data_alignment && (default_pe_align % data_alignment); } unsigned long set_pe_align(struct physical_volume *pv, unsigned long data_alignment) { - unsigned long temp_pe_align; + unsigned long default_pe_align, temp_pe_align; if (pv->pe_align) goto out; - if (data_alignment) + if (data_alignment) { + /* Always use specified data_alignment */ pv->pe_align = data_alignment; + goto out; + } + + default_pe_align = find_config_tree_int(pv->fmt->cmd, + "devices/default_data_alignment", + DEFAULT_DATA_ALIGNMENT); + + if (default_pe_align) + /* align on 1 MiB multiple */ + default_pe_align *= DEFAULT_PE_ALIGN; else - pv->pe_align = MAX((DEFAULT_PE_ALIGN << SECTOR_SHIFT), - lvm_getpagesize()) >> SECTOR_SHIFT; + /* align on 64 KiB multiple (old default) */ + default_pe_align = DEFAULT_PE_ALIGN_OLD; + + pv->pe_align = MAX((default_pe_align << SECTOR_SHIFT), + lvm_getpagesize()) >> SECTOR_SHIFT; if (!pv->dev) goto out; @@ -89,8 +104,8 @@ unsigned long set_pe_align(struct physical_volume *pv, unsigned long data_alignm if (find_config_tree_bool(pv->fmt->cmd, "devices/md_chunk_alignment", DEFAULT_MD_CHUNK_ALIGNMENT)) { temp_pe_align = dev_md_stripe_width(pv->fmt->cmd->sysfs_dir, pv->dev); - if (_alignment_overrides_default(temp_pe_align)) - pv->pe_align = temp_pe_align; + if (_alignment_overrides_default(temp_pe_align, default_pe_align)) + pv->pe_align = MAX(pv->pe_align, temp_pe_align); } /* @@ -104,18 +119,18 @@ unsigned long set_pe_align(struct physical_volume *pv, unsigned long data_alignm "devices/data_alignment_detection", DEFAULT_DATA_ALIGNMENT_DETECTION)) { temp_pe_align = dev_minimum_io_size(pv->fmt->cmd->sysfs_dir, pv->dev); - if (_alignment_overrides_default(temp_pe_align)) - pv->pe_align = temp_pe_align; + if (_alignment_overrides_default(temp_pe_align, default_pe_align)) + pv->pe_align = MAX(pv->pe_align, temp_pe_align); temp_pe_align = dev_optimal_io_size(pv->fmt->cmd->sysfs_dir, pv->dev); - if (_alignment_overrides_default(temp_pe_align)) - pv->pe_align = temp_pe_align; + if (_alignment_overrides_default(temp_pe_align, default_pe_align)) + pv->pe_align = MAX(pv->pe_align, temp_pe_align); } +out: log_very_verbose("%s: Setting PE alignment to %lu sectors.", dev_name(pv->dev), pv->pe_align); -out: return pv->pe_align; } @@ -125,8 +140,11 @@ unsigned long set_pe_align_offset(struct physical_volume *pv, if (pv->pe_align_offset) goto out; - if (data_alignment_offset) + if (data_alignment_offset) { + /* Always use specified data_alignment_offset */ pv->pe_align_offset = data_alignment_offset; + goto out; + } if (!pv->dev) goto out; @@ -142,10 +160,10 @@ unsigned long set_pe_align_offset(struct physical_volume *pv, pv->pe_align_offset = MAX(pv->pe_align_offset, align_offset); } +out: log_very_verbose("%s: Setting PE alignment offset to %lu sectors.", dev_name(pv->dev), pv->pe_align_offset); -out: return pv->pe_align_offset; }