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Commit 75384347 authored by Sahil Mehta's avatar Sahil Mehta Committed by Michael Ellerman
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powerpc/pseries: Implement indexed-count hotplug memory remove 



Indexed-count remove for memory hotplug guarantees that a contiguous block
of <count> lmbs beginning at a specified <index> will be unassigned (NOT
that <count> lmbs will be removed). Because of Qemu's per-DIMM memory
management, the removal of a contiguous block of memory currently
requires a series of individual calls. Indexed-count remove reduces
this series into a single call.

Signed-off-by: default avatarSahil Mehta <sahilmehta17@gmail.com>
Signed-off-by: default avatarNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 333f7b76

arch/powerpc/platforms/pseries/hotplug-memory.c

+98 −0
Original line number Diff line number Diff line
@@ -601,6 +601,94 @@ static int dlpar_memory_readd_by_index(u32 drc_index, struct property *prop) 


	return rc;

}



static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index,

				     struct property *prop)

{

	struct of_drconf_cell *lmbs;

	u32 num_lmbs, *p;

	int i, rc, start_lmb_found;

	int lmbs_available = 0, start_index = 0, end_index;



	pr_info("Attempting to hot-remove %u LMB(s) at %x\n",

		lmbs_to_remove, drc_index);



	if (lmbs_to_remove == 0)

		return -EINVAL;



	p = prop->value;

	num_lmbs = *p++;

	lmbs = (struct of_drconf_cell *)p;

	start_lmb_found = 0;



	/* Navigate to drc_index */

	while (start_index < num_lmbs) {

		if (lmbs[start_index].drc_index == drc_index) {

			start_lmb_found = 1;

			break;

		}



		start_index++;

	}



	if (!start_lmb_found)

		return -EINVAL;



	end_index = start_index + lmbs_to_remove;



	/* Validate that there are enough LMBs to satisfy the request */

	for (i = start_index; i < end_index; i++) {

		if (lmbs[i].flags & DRCONF_MEM_RESERVED)

			break;



		lmbs_available++;

	}



	if (lmbs_available < lmbs_to_remove)

		return -EINVAL;



	for (i = start_index; i < end_index; i++) {

		if (!(lmbs[i].flags & DRCONF_MEM_ASSIGNED))

			continue;



		rc = dlpar_remove_lmb(&lmbs[i]);

		if (rc)

			break;



		lmbs[i].reserved = 1;

	}



	if (rc) {

		pr_err("Memory indexed-count-remove failed, adding any removed LMBs\n");



		for (i = start_index; i < end_index; i++) {

			if (!lmbs[i].reserved)

				continue;



			rc = dlpar_add_lmb(&lmbs[i]);

			if (rc)

				pr_err("Failed to add LMB, drc index %x\n",

				       be32_to_cpu(lmbs[i].drc_index));



			lmbs[i].reserved = 0;

		}

		rc = -EINVAL;

	} else {

		for (i = start_index; i < end_index; i++) {

			if (!lmbs[i].reserved)

				continue;



			dlpar_release_drc(lmbs[i].drc_index);

			pr_info("Memory at %llx (drc index %x) was hot-removed\n",

				lmbs[i].base_addr, lmbs[i].drc_index);



			lmbs[i].reserved = 0;

		}

	}



	return rc;

}



#else

static inline int pseries_remove_memblock(unsigned long base,

					  unsigned int memblock_size)
@@ -632,6 +720,12 @@ static int dlpar_memory_readd_by_index(u32 drc_index, struct property *prop) 
{

	return -EOPNOTSUPP;

}



static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index,

				     struct property *prop)

{

	return -EOPNOTSUPP;

}

#endif /* CONFIG_MEMORY_HOTREMOVE */



static int dlpar_add_lmb(struct of_drconf_cell *lmb)
@@ -915,6 +1009,10 @@ int dlpar_memory(struct pseries_hp_errorlog *hp_elog) 
		} else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX) {

			drc_index = hp_elog->_drc_u.drc_index;

			rc = dlpar_memory_remove_by_index(drc_index, prop);

		} else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_IC) {

			count = hp_elog->_drc_u.ic.count;

			drc_index = hp_elog->_drc_u.ic.index;

			rc = dlpar_memory_remove_by_ic(count, drc_index, prop);

		} else {

			rc = -EINVAL;

		}