f2fs: introduce mempool for {,de}compress intermediate page allocation
If compression feature is on, in scenario of no enough free memory, page refault ratio is higher than before, the root cause is: - {,de}compression flow needs to allocate intermediate pages to store compressed data in cluster, so during their allocation, vm may reclaim mmaped pages. - if above reclaimed pages belong to compressed cluster, during its refault, it may cause more intermediate pages allocation, result in reclaiming more mmaped pages. So this patch introduces a mempool for intermediate page allocation, in order to avoid high refault ratio, by default, number of preallocated page in pool is 512, user can change the number by assigning 'num_compress_pages' parameter during module initialization. Ma Feng found warnings in the original patch and fixed like below. Fix the following sparse warning: fs/f2fs/compress.c:501:5: warning: symbol 'num_compress_pages' was not declared. Should it be static? fs/f2fs/compress.c:530:6: warning: symbol 'f2fs_compress_free_page' was not declared. Should it be static? Reported-by:Hulk Robot <hulkci@huawei.com> Signed-off-by:
Chao Yu <yuchao0@huawei.com> Signed-off-by:
Ma Feng <mafeng.ma@huawei.com> Signed-off-by:
Jaegeuk Kim <jaegeuk@kernel.org>
parent
c1c63387