| Message ID | 1520936552-11586-1-git-send-email-nborisov@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 03/13/2018 06:22 PM, Nikolay Borisov wrote: > This function is the entry to the extent allocator and as such has > quite a number of parameters. Some of those have subtle effects on the > allocation algorithm. Document the parameters. > > Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> > --- > fs/btrfs/extent-tree.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 45 insertions(+) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index bb1861033071..60ece25101ee 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -7961,6 +7961,51 @@ static void dump_space_info(struct btrfs_fs_info *fs_info, > up_read(&info->groups_sem); > } > > +/* > + * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a > + * hole that is at least as big as @num_bytes. > + * > + * @root - The root that will contains this extent > + * > + * @ram_bytes - The amount of space in ram that @num_bytes take. This > + * is used for accounting purposes. This value differs > + * than @num_bytes only in the case of compressed extents. > + * > + * @num_bytes - Number of bytes to allocates on-disk. > + * > + * @min_alloc_size - Indicates the minimum amount of memory that the > + * allocator should try to satisfy. In some cases > + * @num_bytes may be larger than what is required and if > + * the filesystem is fragmented then allocation fails. > + * However, the presence of @min_alloc_size gives a > + * chance to try and satisfy the smaller allocation. > + * > + * @empty_size - A hint that you plan on doing more cow. This is the > + * size in bytes the allocator should try to find free > + * next to the block it returns. This is just a hint and > + * may be ignored by the allocator. > + * > + * @hint_byte - Hint to the allocator to start searching above the byte > + * address passed. It might be ignored. > + * > + * @ins - This key is modified to record the found hole. It will > + * have the following values: > + * ins->objectid == start position > + * ins->flags = BTRFS_EXTENT_ITEM_KEY > + * ins->offset == the size of the hole. > + * > + * @is_data - Boolean flag indicating whether an extent is > + * allocated for data (true) or metadata (false) > + * > + * @delalloc - Boolean flag indicating whether this allocation is for > + * delalloc or not. If 'true' data_rwsem of block groups > + * is going to be acquired. > + * > + * > + * Returns 0 when an allocation succeeded or < 0 when an error occurred. In > + * case -ENOSPC is returned then @ins->offset will contain the size of the > + * largest available hole the allocator managed to find. > + */ > int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes, > u64 num_bytes, u64 min_alloc_size, > u64 empty_size, u64 hint_byte, > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Mar 13, 2018 at 09:56:23PM +0800, Anand Jain wrote: > > > On 03/13/2018 06:22 PM, Nikolay Borisov wrote: > > This function is the entry to the extent allocator and as such has > > quite a number of parameters. Some of those have subtle effects on the > > allocation algorithm. Document the parameters. > > > > Signed-off-by: Nikolay Borisov <nborisov@suse.com> > > Reviewed-by: Anand Jain <anand.jain@oracle.com> Added to next, thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Mar 13, 2018 at 3:22 AM, Nikolay Borisov <nborisov@suse.com> wrote: > This function is the entry to the extent allocator and as such has > quite a number of parameters. Some of those have subtle effects on the > allocation algorithm. Document the parameters. > > Signed-off-by: Nikolay Borisov <nborisov@suse.com> > --- > fs/btrfs/extent-tree.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 45 insertions(+) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index bb1861033071..60ece25101ee 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -7961,6 +7961,51 @@ static void dump_space_info(struct btrfs_fs_info *fs_info, > up_read(&info->groups_sem); > } > > +/* > + * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a > + * hole that is at least as big as @num_bytes. > + * > + * @root - The root that will contains this extent > + * > + * @ram_bytes - The amount of space in ram that @num_bytes take. This > + * is used for accounting purposes. This value differs > + * than @num_bytes only in the case of compressed extents. > + * > + * @num_bytes - Number of bytes to allocates on-disk. > + * > + * @min_alloc_size - Indicates the minimum amount of memory that the Could you please pick another word instead of "memory", like hole or extent or space? Others look good to me. Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com> thanks, liubo > + * allocator should try to satisfy. In some cases > + * @num_bytes may be larger than what is required and if > + * the filesystem is fragmented then allocation fails. > + * However, the presence of @min_alloc_size gives a > + * chance to try and satisfy the smaller allocation. > + * > + * @empty_size - A hint that you plan on doing more cow. This is the > + * size in bytes the allocator should try to find free > + * next to the block it returns. This is just a hint and > + * may be ignored by the allocator. > + * > + * @hint_byte - Hint to the allocator to start searching above the byte > + * address passed. It might be ignored. > + * > + * @ins - This key is modified to record the found hole. It will > + * have the following values: > + * ins->objectid == start position > + * ins->flags = BTRFS_EXTENT_ITEM_KEY > + * ins->offset == the size of the hole. > + * > + * @is_data - Boolean flag indicating whether an extent is > + * allocated for data (true) or metadata (false) > + * > + * @delalloc - Boolean flag indicating whether this allocation is for > + * delalloc or not. If 'true' data_rwsem of block groups > + * is going to be acquired. > + * > + * > + * Returns 0 when an allocation succeeded or < 0 when an error occurred. In > + * case -ENOSPC is returned then @ins->offset will contain the size of the > + * largest available hole the allocator managed to find. > + */ > int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes, > u64 num_bytes, u64 min_alloc_size, > u64 empty_size, u64 hint_byte, > -- > 2.7.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 16.03.2018 20:43, Liu Bo wrote: > On Tue, Mar 13, 2018 at 3:22 AM, Nikolay Borisov <nborisov@suse.com> wrote: >> This function is the entry to the extent allocator and as such has >> quite a number of parameters. Some of those have subtle effects on the >> allocation algorithm. Document the parameters. >> >> Signed-off-by: Nikolay Borisov <nborisov@suse.com> >> --- >> fs/btrfs/extent-tree.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 45 insertions(+) >> >> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c >> index bb1861033071..60ece25101ee 100644 >> --- a/fs/btrfs/extent-tree.c >> +++ b/fs/btrfs/extent-tree.c >> @@ -7961,6 +7961,51 @@ static void dump_space_info(struct btrfs_fs_info *fs_info, >> up_read(&info->groups_sem); >> } >> >> +/* >> + * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a >> + * hole that is at least as big as @num_bytes. >> + * >> + * @root - The root that will contains this extent >> + * >> + * @ram_bytes - The amount of space in ram that @num_bytes take. This >> + * is used for accounting purposes. This value differs >> + * than @num_bytes only in the case of compressed extents. >> + * >> + * @num_bytes - Number of bytes to allocates on-disk. >> + * >> + * @min_alloc_size - Indicates the minimum amount of memory that the > > Could you please pick another word instead of "memory", like hole or > extent or space? Good point, i guess it's a brain fair. I'd rather use "space". I see David has already merged it. David do you mind fixing it in-place? > > Others look good to me. > > Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com> > > thanks, > liubo > >> + * allocator should try to satisfy. In some cases >> + * @num_bytes may be larger than what is required and if >> + * the filesystem is fragmented then allocation fails. >> + * However, the presence of @min_alloc_size gives a >> + * chance to try and satisfy the smaller allocation. >> + * >> + * @empty_size - A hint that you plan on doing more cow. This is the >> + * size in bytes the allocator should try to find free >> + * next to the block it returns. This is just a hint and >> + * may be ignored by the allocator. >> + * >> + * @hint_byte - Hint to the allocator to start searching above the byte >> + * address passed. It might be ignored. >> + * >> + * @ins - This key is modified to record the found hole. It will >> + * have the following values: >> + * ins->objectid == start position >> + * ins->flags = BTRFS_EXTENT_ITEM_KEY >> + * ins->offset == the size of the hole. >> + * >> + * @is_data - Boolean flag indicating whether an extent is >> + * allocated for data (true) or metadata (false) >> + * >> + * @delalloc - Boolean flag indicating whether this allocation is for >> + * delalloc or not. If 'true' data_rwsem of block groups >> + * is going to be acquired. >> + * >> + * >> + * Returns 0 when an allocation succeeded or < 0 when an error occurred. In >> + * case -ENOSPC is returned then @ins->offset will contain the size of the >> + * largest available hole the allocator managed to find. >> + */ >> int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes, >> u64 num_bytes, u64 min_alloc_size, >> u64 empty_size, u64 hint_byte, >> -- >> 2.7.4 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Mar 16, 2018 at 08:44:56PM +0200, Nikolay Borisov wrote: > >> + * @min_alloc_size - Indicates the minimum amount of memory that the > > > > Could you please pick another word instead of "memory", like hole or > > extent or space? > > Good point, i guess it's a brain fair. I'd rather use "space". I see > David has already merged it. David do you mind fixing it in-place? Yes, no problem. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index bb1861033071..60ece25101ee 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -7961,6 +7961,51 @@ static void dump_space_info(struct btrfs_fs_info *fs_info, up_read(&info->groups_sem); } +/* + * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a + * hole that is at least as big as @num_bytes. + * + * @root - The root that will contains this extent + * + * @ram_bytes - The amount of space in ram that @num_bytes take. This + * is used for accounting purposes. This value differs + * than @num_bytes only in the case of compressed extents. + * + * @num_bytes - Number of bytes to allocates on-disk. + * + * @min_alloc_size - Indicates the minimum amount of memory that the + * allocator should try to satisfy. In some cases + * @num_bytes may be larger than what is required and if + * the filesystem is fragmented then allocation fails. + * However, the presence of @min_alloc_size gives a + * chance to try and satisfy the smaller allocation. + * + * @empty_size - A hint that you plan on doing more cow. This is the + * size in bytes the allocator should try to find free + * next to the block it returns. This is just a hint and + * may be ignored by the allocator. + * + * @hint_byte - Hint to the allocator to start searching above the byte + * address passed. It might be ignored. + * + * @ins - This key is modified to record the found hole. It will + * have the following values: + * ins->objectid == start position + * ins->flags = BTRFS_EXTENT_ITEM_KEY + * ins->offset == the size of the hole. + * + * @is_data - Boolean flag indicating whether an extent is + * allocated for data (true) or metadata (false) + * + * @delalloc - Boolean flag indicating whether this allocation is for + * delalloc or not. If 'true' data_rwsem of block groups + * is going to be acquired. + * + * + * Returns 0 when an allocation succeeded or < 0 when an error occurred. In + * case -ENOSPC is returned then @ins->offset will contain the size of the + * largest available hole the allocator managed to find. + */ int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes, u64 num_bytes, u64 min_alloc_size, u64 empty_size, u64 hint_byte,
This function is the entry to the extent allocator and as such has quite a number of parameters. Some of those have subtle effects on the allocation algorithm. Document the parameters. Signed-off-by: Nikolay Borisov <nborisov@suse.com> --- fs/btrfs/extent-tree.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+)