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Date: Tue, 29 Sep 2020 17:24:33 +0800
From: Chao Yu <yuchao0@...wei.com>
To: Jaegeuk Kim <jaegeuk@...nel.org>
CC: <linux-kernel@...r.kernel.org>,
<linux-f2fs-devel@...ts.sourceforge.net>
Subject: Re: [f2fs-dev] [PATCH v2 1/2] f2fs: compress: introduce page array
slab cache
On 2020/9/29 17:15, Chao Yu wrote:
> On 2020/9/29 16:47, Jaegeuk Kim wrote:
>> On 09/29, Chao Yu wrote:
>>> On 2020/9/29 16:23, Jaegeuk Kim wrote:
>>>> I found a bug related to the number of page pointer allocation related to
>>>> nr_cpages.
>>>
>>> Jaegeuk,
>>>
>>> If I didn't miss anything, you mean that nr_cpages could be larger
>>> than nr_rpages, right? the problematic case here is lzo/lzo-rle:
>>>
>>> cc->clen = lzo1x_worst_compress(PAGE_SIZE << cc->log_cluster_size);
>>>
>>> As we can't limited clen as we did for lz4/zstd:
>>>
>>> cc->clen = cc->rlen - PAGE_SIZE - COMPRESS_HEADER_SIZE;
>>
>> Yes, I've seen some memory corruption in lzo test. Here is another patch to fix
>> mem leak.
>>
>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
>> ---
>> fs/f2fs/compress.c | 67 ++++++++++++++++++++++++++++------------------
>> 1 file changed, 41 insertions(+), 26 deletions(-)
>>
>> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
>> index f086ac43ca825..ba2d4897744d8 100644
>> --- a/fs/f2fs/compress.c
>> +++ b/fs/f2fs/compress.c
>> @@ -20,22 +20,20 @@
>> static struct kmem_cache *cic_entry_slab;
>> static struct kmem_cache *dic_entry_slab;
>>
>> -static void *page_array_alloc(struct inode *inode)
>> +static void *page_array_alloc(struct inode *inode, int nr)
>> {
>> struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>> - unsigned int size = sizeof(struct page *) <<
>> - F2FS_I(inode)->i_log_cluster_size;
>> + unsigned int size = sizeof(struct page *) * nr;
>>
>> if (likely(size == sbi->page_array_slab_size))
>> return kmem_cache_zalloc(sbi->page_array_slab, GFP_NOFS);
>> return f2fs_kzalloc(sbi, size, GFP_NOFS);
>> }
>>
>> -static void page_array_free(struct inode *inode, void *pages)
>> +static void page_array_free(struct inode *inode, void *pages, int nr)
>> {
>> struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>> - unsigned int size = sizeof(struct page *) <<
>> - F2FS_I(inode)->i_log_cluster_size;
>> + unsigned int size = sizeof(struct page *) * nr;
>>
>> if (!pages)
>> return;
>> @@ -162,13 +160,13 @@ int f2fs_init_compress_ctx(struct compress_ctx *cc)
>> if (cc->rpages)
>> return 0;
>>
>> - cc->rpages = page_array_alloc(cc->inode);
>> + cc->rpages = page_array_alloc(cc->inode, cc->cluster_size);
>> return cc->rpages ? 0 : -ENOMEM;
>> }
>>
>> void f2fs_destroy_compress_ctx(struct compress_ctx *cc)
>> {
>> - page_array_free(cc->inode, cc->rpages);
>> + page_array_free(cc->inode, cc->rpages, cc->cluster_size);
>> cc->rpages = NULL;
>> cc->nr_rpages = 0;
>> cc->nr_cpages = 0;
>> @@ -602,7 +600,8 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
>> struct f2fs_inode_info *fi = F2FS_I(cc->inode);
>> const struct f2fs_compress_ops *cops =
>> f2fs_cops[fi->i_compress_algorithm];
>> - unsigned int max_len, nr_cpages;
>> + unsigned int max_len, new_nr_cpages;
>> + struct page **new_cpages;
>> int i, ret;
>>
>> trace_f2fs_compress_pages_start(cc->inode, cc->cluster_idx,
>> @@ -617,7 +616,7 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
>> max_len = COMPRESS_HEADER_SIZE + cc->clen;
>> cc->nr_cpages = DIV_ROUND_UP(max_len, PAGE_SIZE);
>>
>> - cc->cpages = page_array_alloc(cc->inode);
>> + cc->cpages = page_array_alloc(cc->inode, cc->nr_cpages);
>
> Well, cc->nr_cpages will be set to cc->nr_rpages - 1 for zstd/lz4 cases, so
> this will make cpages allocation fallback to kmalloc, which can cause more
> memory use.
Could we handle cpages allocation for lzo/lzo-rle separately as:
force_xxx = is_lzo/lzo-rle_algorithm and is_cpages_array_allocation
page_array_alloc(, force_kmalloc)
page_array_free(, force_kfree)
Thanks,
>
> Thanks,
>
>> if (!cc->cpages) {
>> ret = -ENOMEM;
>> goto destroy_compress_ctx;
>> @@ -659,16 +658,28 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
>> for (i = 0; i < COMPRESS_DATA_RESERVED_SIZE; i++)
>> cc->cbuf->reserved[i] = cpu_to_le32(0);
>>
>> - nr_cpages = DIV_ROUND_UP(cc->clen + COMPRESS_HEADER_SIZE, PAGE_SIZE);
>> + new_nr_cpages = DIV_ROUND_UP(cc->clen + COMPRESS_HEADER_SIZE, PAGE_SIZE);
>> +
>> + /* Now we're going to cut unnecessary tail pages */
>> + new_cpages = page_array_alloc(cc->inode, new_nr_cpages);
>> + if (new_cpages) {
>> + ret = -ENOMEM;
>> + goto out_vunmap_cbuf;
>> + }
>>
>> /* zero out any unused part of the last page */
>> memset(&cc->cbuf->cdata[cc->clen], 0,
>> - (nr_cpages * PAGE_SIZE) - (cc->clen + COMPRESS_HEADER_SIZE));
>> + (new_nr_cpages * PAGE_SIZE) -
>> + (cc->clen + COMPRESS_HEADER_SIZE));
>>
>> vm_unmap_ram(cc->cbuf, cc->nr_cpages);
>> vm_unmap_ram(cc->rbuf, cc->cluster_size);
>>
>> - for (i = nr_cpages; i < cc->nr_cpages; i++) {
>> + for (i = 0; i < cc->nr_cpages; i++) {
>> + if (i < new_nr_cpages) {
>> + new_cpages[i] = cc->cpages[i];
>> + continue;
>> + }
>> f2fs_compress_free_page(cc->cpages[i]);
>> cc->cpages[i] = NULL;
>> }
>> @@ -676,7 +687,9 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
>> if (cops->destroy_compress_ctx)
>> cops->destroy_compress_ctx(cc);
>>
>> - cc->nr_cpages = nr_cpages;
>> + page_array_free(cc->inode, cc->cpages, cc->nr_cpages);
>> + cc->cpages = new_cpages;
>> + cc->nr_cpages = new_nr_cpages;
>>
>> trace_f2fs_compress_pages_end(cc->inode, cc->cluster_idx,
>> cc->clen, ret);
>> @@ -691,7 +704,7 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
>> if (cc->cpages[i])
>> f2fs_compress_free_page(cc->cpages[i]);
>> }
>> - page_array_free(cc->inode, cc->cpages);
>> + page_array_free(cc->inode, cc->cpages, cc->nr_cpages);
>> cc->cpages = NULL;
>> destroy_compress_ctx:
>> if (cops->destroy_compress_ctx)
>> @@ -730,7 +743,7 @@ void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity)
>> goto out_free_dic;
>> }
>>
>> - dic->tpages = page_array_alloc(dic->inode);
>> + dic->tpages = page_array_alloc(dic->inode, dic->cluster_size);
>> if (!dic->tpages) {
>> ret = -ENOMEM;
>> goto out_free_dic;
>> @@ -1203,7 +1216,7 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
>> cic->magic = F2FS_COMPRESSED_PAGE_MAGIC;
>> cic->inode = inode;
>> atomic_set(&cic->pending_pages, cc->nr_cpages);
>> - cic->rpages = page_array_alloc(cc->inode);
>> + cic->rpages = page_array_alloc(cc->inode, cc->cluster_size);
>> if (!cic->rpages)
>> goto out_put_cic;
>>
>> @@ -1297,11 +1310,13 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
>> spin_unlock(&fi->i_size_lock);
>>
>> f2fs_put_rpages(cc);
>> + page_array_free(cc->inode, cc->cpages, cc->nr_cpages);
>> + cc->cpages = NULL;
>> f2fs_destroy_compress_ctx(cc);
>> return 0;
>>
>> out_destroy_crypt:
>> - page_array_free(cc->inode, cic->rpages);
>> + page_array_free(cc->inode, cic->rpages, cc->cluster_size);
>>
>> for (--i; i >= 0; i--)
>> fscrypt_finalize_bounce_page(&cc->cpages[i]);
>> @@ -1310,6 +1325,8 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
>> continue;
>> f2fs_put_page(cc->cpages[i], 1);
>> }
>> + page_array_free(cc->inode, cc->cpages, cc->nr_cpages);
>> + cc->cpages = NULL;
>> out_put_cic:
>> kmem_cache_free(cic_entry_slab, cic);
>> out_put_dnode:
>> @@ -1345,7 +1362,7 @@ void f2fs_compress_write_end_io(struct bio *bio, struct page *page)
>> end_page_writeback(cic->rpages[i]);
>> }
>>
>> - page_array_free(cic->inode, cic->rpages);
>> + page_array_free(cic->inode, cic->rpages, cic->nr_rpages);
>> kmem_cache_free(cic_entry_slab, cic);
>> }
>>
>> @@ -1442,8 +1459,6 @@ int f2fs_write_multi_pages(struct compress_ctx *cc,
>>
>> err = f2fs_write_compressed_pages(cc, submitted,
>> wbc, io_type);
>> - page_array_free(cc->inode, cc->cpages);
>> - cc->cpages = NULL;
>> if (!err)
>> return 0;
>> f2fs_bug_on(F2FS_I_SB(cc->inode), err != -EAGAIN);
>> @@ -1468,7 +1483,7 @@ struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc)
>> if (!dic)
>> return ERR_PTR(-ENOMEM);
>>
>> - dic->rpages = page_array_alloc(cc->inode);
>> + dic->rpages = page_array_alloc(cc->inode, cc->cluster_size);
>> if (!dic->rpages) {
>> kmem_cache_free(dic_entry_slab, dic);
>> return ERR_PTR(-ENOMEM);
>> @@ -1487,7 +1502,7 @@ struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc)
>> dic->rpages[i] = cc->rpages[i];
>> dic->nr_rpages = cc->cluster_size;
>>
>> - dic->cpages = page_array_alloc(dic->inode);
>> + dic->cpages = page_array_alloc(dic->inode, dic->nr_cpages);
>> if (!dic->cpages)
>> goto out_free;
>>
>> @@ -1522,7 +1537,7 @@ void f2fs_free_dic(struct decompress_io_ctx *dic)
>> continue;
>> f2fs_compress_free_page(dic->tpages[i]);
>> }
>> - page_array_free(dic->inode, dic->tpages);
>> + page_array_free(dic->inode, dic->tpages, dic->cluster_size);
>> }
>>
>> if (dic->cpages) {
>> @@ -1531,10 +1546,10 @@ void f2fs_free_dic(struct decompress_io_ctx *dic)
>> continue;
>> f2fs_compress_free_page(dic->cpages[i]);
>> }
>> - page_array_free(dic->inode, dic->cpages);
>> + page_array_free(dic->inode, dic->cpages, dic->nr_cpages);
>> }
>>
>> - page_array_free(dic->inode, dic->rpages);
>> + page_array_free(dic->inode, dic->rpages, dic->nr_rpages);
>> kmem_cache_free(dic_entry_slab, dic);
>> }
>>
>>
>
>
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> .
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