From 79f504a2cd3c0b7d953d0015618a2a41559a2cfd Mon Sep 17 00:00:00 2001 From: Chunhai Guo Date: Fri, 6 Sep 2024 06:11:10 -0600 Subject: [PATCH] erofs: allocate more short-lived pages from reserved pool first This patch aims to allocate bvpages and short-lived compressed pages from the reserved pool first. After applying this patch, there are three benefits. 1. It reduces the page allocation time. The bvpages and short-lived compressed pages account for about 4% of the pages allocated from the system in the multi-app launch benchmarks [1]. It reduces the page allocation time accordingly and lowers the likelihood of blockage by page allocation in low memory scenarios. 2. The pages in the reserved pool will be allocated on demand. Currently, bvpages and short-lived compressed pages are short-lived pages allocated from the system, and the pages in the reserved pool all originate from short-lived pages. Consequently, the number of reserved pool pages will increase to z_erofs_rsv_nrpages over time. With this patch, all short-lived pages are allocated from the reserved pool first, so the number of reserved pool pages will only increase when there are not enough pages. Thus, even if z_erofs_rsv_nrpages is set to a large number for specific reasons, the actual number of reserved pool pages may remain low as per demand. In the multi-app launch benchmarks [1], z_erofs_rsv_nrpages is set at 256, while the number of reserved pool pages remains below 64. 3. When erofs cache decompression is disabled (EROFS_ZIP_CACHE_DISABLED), all pages will *only* be allocated from the reserved pool for erofs. This will significantly reduce the memory pressure from erofs. [1] For additional details on the multi-app launch benchmarks, please refer to commit 0f6273ab4637 ("erofs: add a reserved buffer pool for lz4 decompression"). Signed-off-by: Chunhai Guo Reviewed-by: Gao Xiang Reviewed-by: Chao Yu Link: https://lore.kernel.org/r/20240906121110.3701889-1-guochunhai@vivo.com Signed-off-by: Gao Xiang --- fs/erofs/zdata.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index b720dba14edd..8936790618c6 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -196,7 +196,8 @@ static int z_erofs_bvec_enqueue(struct z_erofs_bvec_iter *iter, struct page *nextpage = *candidate_bvpage; if (!nextpage) { - nextpage = erofs_allocpage(pagepool, GFP_KERNEL); + nextpage = __erofs_allocpage(pagepool, GFP_KERNEL, + true); if (!nextpage) return -ENOMEM; set_page_private(nextpage, Z_EROFS_SHORTLIVED_PAGE); @@ -1464,7 +1465,7 @@ repeat: folio_unlock(folio); folio_put(folio); out_allocfolio: - page = erofs_allocpage(&f->pagepool, gfp); + page = __erofs_allocpage(&f->pagepool, gfp, true); spin_lock(&pcl->obj.lockref.lock); if (unlikely(pcl->compressed_bvecs[nr].page != zbv.page)) { if (page)