Messages in this thread Patch in this message | | | Date | Wed, 29 Jul 2020 18:57:55 -0700 | Subject | [PATCH net] RDMA/umem: add a schedule point in ib_umem_get() | From | Eric Dumazet <> |
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Mapping as little as 64GB can take more than 10 seconds, triggering issues on kernels with CONFIG_PREEMPT_NONE=y.
ib_umem_get() already splits the work in 2MB units on x86_64, adding a cond_resched() in the long-lasting loop is enough to solve the issue.
Note that sg_alloc_table() can still use more than 100 ms, which is also problematic. This might be addressed later in ib_umem_add_sg_table(), adding new blocks in sgl on demand.
Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Doug Ledford <dledford@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: linux-rdma@vger.kernel.org --- drivers/infiniband/core/umem.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c index 82455a1392f1d19c96ae956f0bd4e93e3a52d29c..831bff8d52e547834e9e04064127fbb280595126 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -261,6 +261,7 @@ struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr, sg = umem->sg_head.sgl; while (npages) { + cond_resched(); ret = pin_user_pages_fast(cur_base, min_t(unsigned long, npages, PAGE_SIZE / -- 2.28.0.rc0.142.g3c755180ce-goog
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