Even with inplace decompression, sometimes extra temporary buffers are still needed for decompression. In low-memory scenarios, it would be better to try to allocate with GFP_NOWAIT on readahead first. That can help reduce the time spent on page allocation under memory pressure.
There is an average reduction of 21% in page allocation time under multi-app launch benchmark workload [1] on ARM64 Android devices running the 5.15 kernel with an 8-core CPU and 8GB of memory. [1] https://lore.kernel.org/r/[email protected] Suggested-by: Gao Xiang <[email protected]> Signed-off-by: Chunhai Guo <[email protected]> --- fs/erofs/compress.h | 5 ++--- fs/erofs/decompressor.c | 5 +++-- fs/erofs/decompressor_deflate.c | 19 +++++++++++++------ fs/erofs/decompressor_lzma.c | 17 ++++++++++++----- fs/erofs/zdata.c | 16 ++++++++++++---- 5 files changed, 42 insertions(+), 20 deletions(-) diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h index 279933e007d2..7cc5841577b2 100644 --- a/fs/erofs/compress.h +++ b/fs/erofs/compress.h @@ -11,13 +11,12 @@ struct z_erofs_decompress_req { struct super_block *sb; struct page **in, **out; - unsigned short pageofs_in, pageofs_out; unsigned int inputsize, outputsize; - /* indicate the algorithm will be used for decompression */ - unsigned int alg; + unsigned int alg; /* the algorithm for decompression */ bool inplace_io, partial_decoding, fillgaps; + gfp_t gfp; /* allocation flags for extra temporary buffers */ }; struct z_erofs_decompressor { diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c index 1d65b9f60a39..ef2b08ec9830 100644 --- a/fs/erofs/decompressor.c +++ b/fs/erofs/decompressor.c @@ -111,8 +111,9 @@ static int z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx *ctx, victim = availables[--top]; get_page(victim); } else { - victim = erofs_allocpage(pagepool, - GFP_KERNEL | __GFP_NOFAIL); + victim = erofs_allocpage(pagepool, rq->gfp); + if (!victim) + return -ENOMEM; set_page_private(victim, Z_EROFS_SHORTLIVED_PAGE); } rq->out[i] = victim; diff --git a/fs/erofs/decompressor_deflate.c b/fs/erofs/decompressor_deflate.c index 4a64a9c91dd3..b98872058abe 100644 --- a/fs/erofs/decompressor_deflate.c +++ b/fs/erofs/decompressor_deflate.c @@ -95,7 +95,7 @@ int z_erofs_load_deflate_config(struct super_block *sb, } int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq, - struct page **pagepool) + struct page **pgpl) { const unsigned int nrpages_out = PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT; @@ -158,8 +158,12 @@ int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq, strm->z.avail_out = min_t(u32, outsz, PAGE_SIZE - pofs); outsz -= strm->z.avail_out; if (!rq->out[no]) { - rq->out[no] = erofs_allocpage(pagepool, - GFP_KERNEL | __GFP_NOFAIL); + rq->out[no] = erofs_allocpage(pgpl, rq->gfp); + if (!rq->out[no]) { + kout = NULL; + err = -ENOMEM; + break; + } set_page_private(rq->out[no], Z_EROFS_SHORTLIVED_PAGE); } @@ -211,8 +215,11 @@ int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq, DBG_BUGON(erofs_page_is_managed(EROFS_SB(sb), rq->in[j])); - tmppage = erofs_allocpage(pagepool, - GFP_KERNEL | __GFP_NOFAIL); + tmppage = erofs_allocpage(pgpl, rq->gfp); + if (!tmppage) { + err = -ENOMEM; + goto failed; + } set_page_private(tmppage, Z_EROFS_SHORTLIVED_PAGE); copy_highpage(tmppage, rq->in[j]); rq->in[j] = tmppage; @@ -230,7 +237,7 @@ int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq, break; } } - +failed: if (zlib_inflateEnd(&strm->z) != Z_OK && !err) err = -EIO; if (kout) diff --git a/fs/erofs/decompressor_lzma.c b/fs/erofs/decompressor_lzma.c index 2dd14f99c1dc..6ca357d83cfa 100644 --- a/fs/erofs/decompressor_lzma.c +++ b/fs/erofs/decompressor_lzma.c @@ -148,7 +148,7 @@ int z_erofs_load_lzma_config(struct super_block *sb, } int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq, - struct page **pagepool) + struct page **pgpl) { const unsigned int nrpages_out = PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT; @@ -215,8 +215,11 @@ int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq, PAGE_SIZE - pageofs); outlen -= strm->buf.out_size; if (!rq->out[no] && rq->fillgaps) { /* deduped */ - rq->out[no] = erofs_allocpage(pagepool, - GFP_KERNEL | __GFP_NOFAIL); + rq->out[no] = erofs_allocpage(pgpl, rq->gfp); + if (!rq->out[no]) { + err = -ENOMEM; + break; + } set_page_private(rq->out[no], Z_EROFS_SHORTLIVED_PAGE); } @@ -258,8 +261,11 @@ int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq, DBG_BUGON(erofs_page_is_managed(EROFS_SB(rq->sb), rq->in[j])); - tmppage = erofs_allocpage(pagepool, - GFP_KERNEL | __GFP_NOFAIL); + tmppage = erofs_allocpage(pgpl, rq->gfp); + if (!tmppage) { + err = -ENOMEM; + goto failed; + } set_page_private(tmppage, Z_EROFS_SHORTLIVED_PAGE); copy_highpage(tmppage, rq->in[j]); rq->in[j] = tmppage; @@ -277,6 +283,7 @@ int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq, break; } } +failed: if (no < nrpages_out && strm->buf.out) kunmap(rq->out[no]); if (ni < nrpages_in) diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index 692c0c39be63..a293de2a60ed 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -82,6 +82,9 @@ struct z_erofs_pcluster { /* L: indicate several pageofs_outs or not */ bool multibases; + /* L: whether extra buffer allocations are best-effort */ + bool besteffort; + /* A: compressed bvecs (can be cached or inplaced pages) */ struct z_erofs_bvec compressed_bvecs[]; }; @@ -964,7 +967,7 @@ static int z_erofs_read_fragment(struct super_block *sb, struct page *page, } static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, - struct page *page) + struct page *page, bool ra) { struct inode *const inode = fe->inode; struct erofs_map_blocks *const map = &fe->map; @@ -1014,6 +1017,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, err = z_erofs_pcluster_begin(fe); if (err) goto out; + fe->pcl->besteffort |= !ra; } /* @@ -1280,7 +1284,11 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be, .inplace_io = overlapped, .partial_decoding = pcl->partial, .fillgaps = pcl->multibases, + .gfp = pcl->besteffort ? + GFP_KERNEL | __GFP_NOFAIL : + GFP_NOWAIT | __GFP_NORETRY }, be->pagepool); + pcl->besteffort = false; /* must handle all compressed pages before actual file pages */ if (z_erofs_is_inline_pcluster(pcl)) { @@ -1785,7 +1793,7 @@ static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f, if (PageUptodate(page)) unlock_page(page); else - (void)z_erofs_do_read_page(f, page); + (void)z_erofs_do_read_page(f, page, !!rac); put_page(page); } @@ -1806,7 +1814,7 @@ static int z_erofs_read_folio(struct file *file, struct folio *folio) f.headoffset = (erofs_off_t)folio->index << PAGE_SHIFT; z_erofs_pcluster_readmore(&f, NULL, true); - err = z_erofs_do_read_page(&f, &folio->page); + err = z_erofs_do_read_page(&f, &folio->page, false); z_erofs_pcluster_readmore(&f, NULL, false); z_erofs_pcluster_end(&f); @@ -1847,7 +1855,7 @@ static void z_erofs_readahead(struct readahead_control *rac) folio = head; head = folio_get_private(folio); - err = z_erofs_do_read_page(&f, &folio->page); + err = z_erofs_do_read_page(&f, &folio->page, true); if (err && err != -EINTR) erofs_err(inode->i_sb, "readahead error at folio %lu @ nid %llu", folio->index, EROFS_I(inode)->nid); -- 2.25.1
