Commit 2f6274e4 authored by farah kassabri's avatar farah kassabri Committed by Oded Gabbay
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habanalabs: avoid soft lockup bug upon mapping error 



Add a little sleep between page unmappings in case mapping of
large number of host pages failed, in order to
avoid soft lockup bug during the rollback.

Signed-off-by: default avatarfarah kassabri <fkassabri@habana.ai>
Reviewed-by: default avatarOded Gabbay <ogabbay@kernel.org>
Signed-off-by: default avatarOded Gabbay <ogabbay@kernel.org>
parent d661d799

drivers/misc/habanalabs/common/memory.c

+17 −3
Original line number Diff line number Diff line
@@ -857,6 +857,7 @@ static int map_phys_pg_pack(struct hl_ctx *ctx, u64 vaddr, 
	u64 next_vaddr = vaddr, paddr, mapped_pg_cnt = 0, i;

	u32 page_size = phys_pg_pack->page_size;

	int rc = 0;

	bool is_host_addr;



	for (i = 0 ; i < phys_pg_pack->npages ; i++) {

		paddr = phys_pg_pack->pages[i];
@@ -878,6 +879,8 @@ static int map_phys_pg_pack(struct hl_ctx *ctx, u64 vaddr, 
	return 0;



err:

	is_host_addr = !hl_is_dram_va(hdev, vaddr);



	next_vaddr = vaddr;

	for (i = 0 ; i < mapped_pg_cnt ; i++) {

		if (hl_mmu_unmap_page(ctx, next_vaddr, page_size,
@@ -888,6 +891,17 @@ static int map_phys_pg_pack(struct hl_ctx *ctx, u64 vaddr, 
					phys_pg_pack->pages[i], page_size);



		next_vaddr += page_size;



		/*

		 * unmapping on Palladium can be really long, so avoid a CPU

		 * soft lockup bug by sleeping a little between unmapping pages

		 *

		 * In addition, on host num of pages could be huge,

		 * because page size could be 4KB, so when unmapping host

		 * pages sleep every 32K pages to avoid soft lockup

		 */

		if (hdev->pldm || (is_host_addr && (i & 0x7FFF) == 0))

			usleep_range(50, 200);

	}



	return rc;
@@ -921,9 +935,9 @@ static void unmap_phys_pg_pack(struct hl_ctx *ctx, u64 vaddr, 
		 * unmapping on Palladium can be really long, so avoid a CPU

		 * soft lockup bug by sleeping a little between unmapping pages

		 *

		 * In addition, when unmapping host memory we pass through

		 * the Linux kernel to unpin the pages and that takes a long

		 * time. Therefore, sleep every 32K pages to avoid soft lockup

		 * In addition, on host num of pages could be huge,

		 * because page size could be 4KB, so when unmapping host

		 * pages sleep every 32K pages to avoid soft lockup

		 */

		if (hdev->pldm || (is_host_addr && (i & 0x7FFF) == 0))

			usleep_range(50, 200);