Re: [PATCH v2] f2fs: allocate memory in batch in build_sit_info()

From: Chao Yu
Date: Tue Aug 20 2019 - 05:12:31 EST


On 2019/8/20 4:20, Jaegeuk Kim wrote:
> On 07/26, Chao Yu wrote:
>> build_sit_info() allocate all bitmaps for each segment one by one,
>> it's quite low efficiency, this pach changes to allocate large
>> continuous memory at a time, and divide it and assign for each bitmaps
>> of segment. For large size image, it can expect improving its mount
>> speed.
>
> Hmm, I hit a kernel panic when mounting a partition during fault injection test:
>
> 726 #ifdef CONFIG_F2FS_CHECK_FS
> 727 if (f2fs_test_bit(offset, sit_i->sit_bitmap) !=
> 728 f2fs_test_bit(offset, sit_i->sit_bitmap_mir))
> 729 f2fs_bug_on(sbi, 1);
> 730 #endif

We didn't change anything about sit_i->sit_bitmap{_mir,}, it's so wired we panic
here... :(

I double check the change, but find nothing suspicious, btw, my fault injection
testcase shows normal.

Jaegeuk, do you have any idea about this issue?

Thanks,

>
> For your information, I'm testing without this patch.
>
> Thanks,
>
>>
>> Signed-off-by: Chen Gong <gongchen4@xxxxxxxxxx>
>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>> ---
>> v2:
>> - fix warning triggered in kmalloc() if requested memory size exceeds 4MB.
>> fs/f2fs/segment.c | 51 +++++++++++++++++++++--------------------------
>> fs/f2fs/segment.h | 1 +
>> 2 files changed, 24 insertions(+), 28 deletions(-)
>>
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index a661ac32e829..d720eacd9c57 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -3941,7 +3941,7 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
>> struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
>> struct sit_info *sit_i;
>> unsigned int sit_segs, start;
>> - char *src_bitmap;
>> + char *src_bitmap, *bitmap;
>> unsigned int bitmap_size;
>>
>> /* allocate memory for SIT information */
>> @@ -3964,27 +3964,31 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
>> if (!sit_i->dirty_sentries_bitmap)
>> return -ENOMEM;
>>
>> +#ifdef CONFIG_F2FS_CHECK_FS
>> + bitmap_size = MAIN_SEGS(sbi) * SIT_VBLOCK_MAP_SIZE * 4;
>> +#else
>> + bitmap_size = MAIN_SEGS(sbi) * SIT_VBLOCK_MAP_SIZE * 3;
>> +#endif
>> + sit_i->bitmap = f2fs_kvzalloc(sbi, bitmap_size, GFP_KERNEL);
>> + if (!sit_i->bitmap)
>> + return -ENOMEM;
>> +
>> + bitmap = sit_i->bitmap;
>> +
>> for (start = 0; start < MAIN_SEGS(sbi); start++) {
>> - sit_i->sentries[start].cur_valid_map
>> - = f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
>> - sit_i->sentries[start].ckpt_valid_map
>> - = f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
>> - if (!sit_i->sentries[start].cur_valid_map ||
>> - !sit_i->sentries[start].ckpt_valid_map)
>> - return -ENOMEM;
>> + sit_i->sentries[start].cur_valid_map = bitmap;
>> + bitmap += SIT_VBLOCK_MAP_SIZE;
>> +
>> + sit_i->sentries[start].ckpt_valid_map = bitmap;
>> + bitmap += SIT_VBLOCK_MAP_SIZE;
>>
>> #ifdef CONFIG_F2FS_CHECK_FS
>> - sit_i->sentries[start].cur_valid_map_mir
>> - = f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
>> - if (!sit_i->sentries[start].cur_valid_map_mir)
>> - return -ENOMEM;
>> + sit_i->sentries[start].cur_valid_map_mir = bitmap;
>> + bitmap += SIT_VBLOCK_MAP_SIZE;
>> #endif
>>
>> - sit_i->sentries[start].discard_map
>> - = f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE,
>> - GFP_KERNEL);
>> - if (!sit_i->sentries[start].discard_map)
>> - return -ENOMEM;
>> + sit_i->sentries[start].discard_map = bitmap;
>> + bitmap += SIT_VBLOCK_MAP_SIZE;
>> }
>>
>> sit_i->tmp_map = f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
>> @@ -4492,21 +4496,12 @@ static void destroy_free_segmap(struct f2fs_sb_info *sbi)
>> static void destroy_sit_info(struct f2fs_sb_info *sbi)
>> {
>> struct sit_info *sit_i = SIT_I(sbi);
>> - unsigned int start;
>>
>> if (!sit_i)
>> return;
>>
>> - if (sit_i->sentries) {
>> - for (start = 0; start < MAIN_SEGS(sbi); start++) {
>> - kvfree(sit_i->sentries[start].cur_valid_map);
>> -#ifdef CONFIG_F2FS_CHECK_FS
>> - kvfree(sit_i->sentries[start].cur_valid_map_mir);
>> -#endif
>> - kvfree(sit_i->sentries[start].ckpt_valid_map);
>> - kvfree(sit_i->sentries[start].discard_map);
>> - }
>> - }
>> + if (sit_i->sentries)
>> + kvfree(sit_i->bitmap);
>> kvfree(sit_i->tmp_map);
>>
>> kvfree(sit_i->sentries);
>> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
>> index b74602813a05..ec4d568fd58c 100644
>> --- a/fs/f2fs/segment.h
>> +++ b/fs/f2fs/segment.h
>> @@ -226,6 +226,7 @@ struct sit_info {
>> block_t sit_base_addr; /* start block address of SIT area */
>> block_t sit_blocks; /* # of blocks used by SIT area */
>> block_t written_valid_blocks; /* # of valid blocks in main area */
>> + char *bitmap; /* all bitmaps pointer */
>> char *sit_bitmap; /* SIT bitmap pointer */
>> #ifdef CONFIG_F2FS_CHECK_FS
>> char *sit_bitmap_mir; /* SIT bitmap mirror */
>> --
>> 2.18.0.rc1
> .
>