powerpc/nvdimm: use H_SCM_QUERY hcall on H_OVERLAP error (faa6d211) · Commits · 戴 / test

Right now we force an unbind of SCM memory at drcindex on H_OVERLAP error. This really slows down operations like kexec where we get the H_OVERLAP error because we don't go through a full hypervisor re init. H_OVERLAP error for a H_SCM_BIND_MEM hcall indicates that SCM memory at drc index is already bound. Since we don't specify a logical memory address for bind hcall, we can use the H_SCM_QUERY hcall to query the already bound logical address. Boot time difference with and without patch is: [ 5.583617] IOMMU table initialized, virtual merging enabled [ 5.603041] papr_scm ibm,persistent-memory:ibm,pmemory@44104001: Retrying bind after unbinding [ 301.514221] papr_scm ibm,persistent-memory:ibm,pmemory@44108001: Retrying bind after unbinding [ 340.057238] hv-24x7: read 1530 catalog entries, created 537 event attrs (0 failures), 275 descs after fix [ 5.101572] IOMMU table initialized, virtual merging enabled [ 5.116984] papr_scm ibm,persistent-memory:ibm,pmemory@44104001: Querying SCM details [ 5.117223] papr_scm ibm,persistent-memory:ibm,pmemory@44108001: Querying SCM details [ 5.120530] hv-24x7: read 1530 catalog entries, created 537 event attrs (0 failures), 275 descs Signed-off-by:

Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by:

Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190903123452.28620-2-aneesh.kumar@linux.ibm.com

arch/powerpc/platforms/pseries/papr_scm.c

+40 −8

Original line number	Diff line number	Diff line
		@@ -65,10 +65,8 @@ static int drc_pmem_bind(struct papr_scm_priv *p)
		cond_resched();
		} while (rc == H_BUSY);

		if (rc) {
		dev_err(&p->pdev->dev, "bind err: %lld\n", rc);
		if (rc)
		return rc;
		}

		p->bound_addr = saved;
		dev_dbg(&p->pdev->dev, "bound drc 0x%x to %pR\n", p->drc_index, &p->res);
		@@ -110,6 +108,42 @@ static void drc_pmem_unbind(struct papr_scm_priv *p)
		return;
		}

		static int drc_pmem_query_n_bind(struct papr_scm_priv *p)
		{
		unsigned long start_addr;
		unsigned long end_addr;
		unsigned long ret[PLPAR_HCALL_BUFSIZE];
		int64_t rc;


		rc = plpar_hcall(H_SCM_QUERY_BLOCK_MEM_BINDING, ret,
		p->drc_index, 0);
		if (rc)
		goto err_out;
		start_addr = ret[0];

		/* Make sure the full region is bound. */
		rc = plpar_hcall(H_SCM_QUERY_BLOCK_MEM_BINDING, ret,
		p->drc_index, p->blocks - 1);
		if (rc)
		goto err_out;
		end_addr = ret[0];

		if ((end_addr - start_addr) != ((p->blocks - 1) * p->block_size))
		goto err_out;

		p->bound_addr = start_addr;
		dev_dbg(&p->pdev->dev, "bound drc 0x%x to %pR\n", p->drc_index, &p->res);
		return rc;

		err_out:
		dev_info(&p->pdev->dev,
		"Failed to query, trying an unbind followed by bind");
		drc_pmem_unbind(p);
		return drc_pmem_bind(p);
		}


		static int papr_scm_meta_get(struct papr_scm_priv *p,
		struct nd_cmd_get_config_data_hdr *hdr)
		{
		@@ -430,13 +464,11 @@ static int papr_scm_probe(struct platform_device *pdev)
		rc = drc_pmem_bind(p);

		/* If phyp says drc memory still bound then force unbound and retry */
		if (rc == H_OVERLAP) {
		dev_warn(&pdev->dev, "Retrying bind after unbinding\n");
		drc_pmem_unbind(p);
		rc = drc_pmem_bind(p);
		}
		if (rc == H_OVERLAP)
		rc = drc_pmem_query_n_bind(p);

		if (rc != H_SUCCESS) {
		dev_err(&p->pdev->dev, "bind err: %d\n", rc);
		rc = -ENXIO;
		goto err;
		}

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