Fix page allocation failure in kcalloc by converting the large 1-dimensional array into a 2-dimensional array of order-0 (4KB) pages. This eliminates the need for non-order-0 allocations, improving allocation reliability under memory pressure. The 2D array ensures virtual contiguity for the caller maintaining functional equivalence.
Related to #VSTOR-112413 https://virtuozzo.atlassian.net/browse/VSTOR-112413 Signed-off-by: Liu Kui <kui....@virtuozzo.com> --- fs/fuse/kio/pcs/pcs_mr.c | 55 +++++++++++++++++++++++++--------------- fs/fuse/kio/pcs/pcs_mr.h | 21 ++++++++++----- 2 files changed, 50 insertions(+), 26 deletions(-) diff --git a/fs/fuse/kio/pcs/pcs_mr.c b/fs/fuse/kio/pcs/pcs_mr.c index cbd3b440dd1b..8e1dbc1121ce 100644 --- a/fs/fuse/kio/pcs/pcs_mr.c +++ b/fs/fuse/kio/pcs/pcs_mr.c @@ -13,11 +13,18 @@ void pcs_umem_release(struct pcs_umem *umem) { struct mm_struct *mm_s = umem->mm; + int i, npages = umem->npages; - unpin_user_pages(umem->pages, umem->npages); + for (i = 0; npages; i++) { + int to_free = min_t(int, PCS_PAGES_PER_CHUNK, npages); + + unpin_user_pages(umem->page_chunk[i].pages, to_free); + kfree(umem->page_chunk[i].pages); + npages -= to_free; + } atomic64_sub(umem->npages, &mm_s->pinned_vm); mmdrop(mm_s); - kfree(umem->pages); + kfree(umem->page_chunk); kfree(umem); } @@ -27,14 +34,13 @@ void pcs_umem_release(struct pcs_umem *umem) struct pcs_umem *pcs_umem_get(u64 start, u64 len) { struct pcs_umem *umem = NULL; - struct page **pages; - int npages; - u64 fp_va; struct mm_struct *mm_s; - int got, ret; + u64 fp_va; + int npages, nchunks, i, ret; fp_va = start & PAGE_MASK; npages = PAGE_ALIGN(start + len - fp_va) >> PAGE_SHIFT; + nchunks = (npages >> PCS_PAGE_CHUNK_SHIFT) + 1; umem = kzalloc(sizeof(*umem), GFP_KERNEL); if (!umem) @@ -48,25 +54,34 @@ struct pcs_umem *pcs_umem_get(u64 start, u64 len) mmap_read_lock(mm_s); umem->fp_addr = fp_va; - umem->pages = kcalloc(npages, sizeof(struct page *), GFP_KERNEL); - if (!umem->pages) { + umem->page_chunk = kcalloc(nchunks, sizeof(struct pcs_page_chunk *), GFP_KERNEL); + if (!umem->page_chunk) { ret = -ENOMEM; goto out_err; } - got = 0; - while (npages) { - pages = &umem->pages[got]; - ret = pin_user_pages(fp_va, npages, FOLL_WRITE | FOLL_LONGTERM, pages, NULL); - if (ret < 0) - goto out_err; + for (i = 0; npages; i++) { + int n = min_t(int, npages, PCS_PAGES_PER_CHUNK); + struct page **pages = kcalloc(n, sizeof(struct page *), GFP_KERNEL); - WARN_ON(ret == 0); - umem->npages += ret; - atomic64_add(ret, &mm_s->pinned_vm); - fp_va += ret * PAGE_SIZE; - npages -= ret; - got += ret; + if (!pages) { + ret = -ENOMEM; + goto out_err; + } + umem->page_chunk[i].pages = pages; + + while (n) { + ret = pin_user_pages(fp_va, n, FOLL_WRITE | FOLL_LONGTERM, pages, NULL); + if (ret < 0) + goto out_err; + + atomic64_add(ret, &mm_s->pinned_vm); + umem->npages += ret; + fp_va += ret * PAGE_SIZE; + pages += ret; + n -= ret; + npages -= ret; + } } mmap_read_unlock(mm_s); diff --git a/fs/fuse/kio/pcs/pcs_mr.h b/fs/fuse/kio/pcs/pcs_mr.h index dae9931d9967..64f237f57dec 100644 --- a/fs/fuse/kio/pcs/pcs_mr.h +++ b/fs/fuse/kio/pcs/pcs_mr.h @@ -11,6 +11,8 @@ struct pcs_umem; #define PCS_MAX_MR 0x10000 +#define PCS_PAGE_CHUNK_SHIFT 9 +#define PCS_PAGES_PER_CHUNK (1 << PCS_PAGE_CHUNK_SHIFT) struct pcs_mr_set { struct xarray mr_xa; /* array of registered MRs*/ @@ -18,10 +20,15 @@ struct pcs_mr_set { atomic_t mr_num; /* number of registered MRs*/ }; +struct pcs_page_chunk +{ + struct page **pages; /* array of pinned pages */ +}; + struct pcs_umem { - u64 fp_addr; /* First page base address */ - int npages; /* number of pinned pages */ - struct page **pages; /* array of pinned pages */ + struct pcs_page_chunk *page_chunk; + int npages; /* number of pinned pages */ + u64 fp_addr; /* First page base address */ struct mm_struct *mm; /* mm the memory belongs to */ }; @@ -40,10 +47,12 @@ struct pcs_mr { */ static inline struct page *pcs_umem_page(struct pcs_umem *umem, u64 addr) { - unsigned int idx = (addr - umem->fp_addr) >> PAGE_SHIFT; + unsigned int page_idx = (addr - umem->fp_addr) >> PAGE_SHIFT; + unsigned int chunk_idx = page_idx >> PCS_PAGE_CHUNK_SHIFT; + unsigned int page_in_chunk = page_idx & (PCS_PAGES_PER_CHUNK - 1); - if (likely(idx < umem->npages)) - return umem->pages[idx]; + if (likely(page_idx < umem->npages)) + return umem->page_chunk[chunk_idx].pages[page_in_chunk]; return NULL; } -- 2.39.5 (Apple Git-154) _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel