Re: [PATCH] mlx4_core: allocate 4KB ICM chunks
On 5/11/2018 3:27 AM, Håkon Bugge wrote: On 11 May 2018, at 01:31, Qing Huangwrote: When a system is under memory presure (high usage with fragments), the original 256KB ICM chunk allocations will likely trigger kernel memory management to enter slow path doing memory compact/migration ops in order to complete high order memory allocations. When that happens, user processes calling uverb APIs may get stuck for more than 120s easily even though there are a lot of free pages in smaller chunks available in the system. Syslog: ... Dec 10 09:04:51 slcc03db02 kernel: [397078.572732] INFO: task oracle_205573_e:205573 blocked for more than 120 seconds. ... With 4KB ICM chunk size, the above issue is fixed. However in order to support 4KB ICM chunk size, we need to fix another issue in large size kcalloc allocations. E.g. Setting log_num_mtt=30 requires 1G mtt entries. With the 4KB ICM chunk size, each ICM chunk can only hold 512 mtt entries (8 bytes for each mtt entry). So we need a 16MB allocation for a table->icm pointer array to hold 2M pointers which can easily cause kcalloc to fail. The solution is to use vzalloc to replace kcalloc. There is no need for contiguous memory pages for a driver meta data structure (no need of DMA ops). Signed-off-by: Qing Huang Acked-by: Daniel Jurgens --- drivers/net/ethernet/mellanox/mlx4/icm.c | 14 +++--- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/icm.c b/drivers/net/ethernet/mellanox/mlx4/icm.c index a822f7a..2b17a4b 100644 --- a/drivers/net/ethernet/mellanox/mlx4/icm.c +++ b/drivers/net/ethernet/mellanox/mlx4/icm.c @@ -43,12 +43,12 @@ #include "fw.h" /* - * We allocate in as big chunks as we can, up to a maximum of 256 KB - * per chunk. + * We allocate in 4KB page size chunks to avoid high order memory + * allocations in fragmented/high usage memory situation. */ enum { - MLX4_ICM_ALLOC_SIZE = 1 << 18, - MLX4_TABLE_CHUNK_SIZE = 1 << 18 + MLX4_ICM_ALLOC_SIZE = 1 << 12, + MLX4_TABLE_CHUNK_SIZE = 1 << 12 Shouldn’t these be the arch’s page size order? E.g., if running on SPARC, the hw page size is 8KiB. Good point on supporting wider range of architectures. I got tunnel vision when fixing this on our x64 lab machines. Will send an v2 patch. Thanks, Qing Thxs, Håkon }; static void mlx4_free_icm_pages(struct mlx4_dev *dev, struct mlx4_icm_chunk *chunk) @@ -400,7 +400,7 @@ int mlx4_init_icm_table(struct mlx4_dev *dev, struct mlx4_icm_table *table, obj_per_chunk = MLX4_TABLE_CHUNK_SIZE / obj_size; num_icm = (nobj + obj_per_chunk - 1) / obj_per_chunk; - table->icm = kcalloc(num_icm, sizeof(*table->icm), GFP_KERNEL); + table->icm = vzalloc(num_icm * sizeof(*table->icm)); if (!table->icm) return -ENOMEM; table->virt = virt; @@ -446,7 +446,7 @@ int mlx4_init_icm_table(struct mlx4_dev *dev, struct mlx4_icm_table *table, mlx4_free_icm(dev, table->icm[i], use_coherent); } - kfree(table->icm); + vfree(table->icm); return -ENOMEM; } @@ -462,5 +462,5 @@ void mlx4_cleanup_icm_table(struct mlx4_dev *dev, struct mlx4_icm_table *table) mlx4_free_icm(dev, table->icm[i], table->coherent); } - kfree(table->icm); + vfree(table->icm); } -- 2.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message tomajord...@vger.kernel.org More majordomo info athttp://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message tomajord...@vger.kernel.org More majordomo info athttp://vger.kernel.org/majordomo-info.html
Re: [PATCH] mlx4_core: allocate 4KB ICM chunks
> On 11 May 2018, at 01:31, Qing Huangwrote: > > When a system is under memory presure (high usage with fragments), > the original 256KB ICM chunk allocations will likely trigger kernel > memory management to enter slow path doing memory compact/migration > ops in order to complete high order memory allocations. > > When that happens, user processes calling uverb APIs may get stuck > for more than 120s easily even though there are a lot of free pages > in smaller chunks available in the system. > > Syslog: > ... > Dec 10 09:04:51 slcc03db02 kernel: [397078.572732] INFO: task > oracle_205573_e:205573 blocked for more than 120 seconds. > ... > > With 4KB ICM chunk size, the above issue is fixed. > > However in order to support 4KB ICM chunk size, we need to fix another > issue in large size kcalloc allocations. > > E.g. > Setting log_num_mtt=30 requires 1G mtt entries. With the 4KB ICM chunk > size, each ICM chunk can only hold 512 mtt entries (8 bytes for each mtt > entry). So we need a 16MB allocation for a table->icm pointer array to > hold 2M pointers which can easily cause kcalloc to fail. > > The solution is to use vzalloc to replace kcalloc. There is no need > for contiguous memory pages for a driver meta data structure (no need > of DMA ops). > > Signed-off-by: Qing Huang > Acked-by: Daniel Jurgens > --- > drivers/net/ethernet/mellanox/mlx4/icm.c | 14 +++--- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/drivers/net/ethernet/mellanox/mlx4/icm.c > b/drivers/net/ethernet/mellanox/mlx4/icm.c > index a822f7a..2b17a4b 100644 > --- a/drivers/net/ethernet/mellanox/mlx4/icm.c > +++ b/drivers/net/ethernet/mellanox/mlx4/icm.c > @@ -43,12 +43,12 @@ > #include "fw.h" > > /* > - * We allocate in as big chunks as we can, up to a maximum of 256 KB > - * per chunk. > + * We allocate in 4KB page size chunks to avoid high order memory > + * allocations in fragmented/high usage memory situation. > */ > enum { > - MLX4_ICM_ALLOC_SIZE = 1 << 18, > - MLX4_TABLE_CHUNK_SIZE = 1 << 18 > + MLX4_ICM_ALLOC_SIZE = 1 << 12, > + MLX4_TABLE_CHUNK_SIZE = 1 << 12 Shouldn’t these be the arch’s page size order? E.g., if running on SPARC, the hw page size is 8KiB. Thxs, Håkon > }; > > static void mlx4_free_icm_pages(struct mlx4_dev *dev, struct mlx4_icm_chunk > *chunk) > @@ -400,7 +400,7 @@ int mlx4_init_icm_table(struct mlx4_dev *dev, struct > mlx4_icm_table *table, > obj_per_chunk = MLX4_TABLE_CHUNK_SIZE / obj_size; > num_icm = (nobj + obj_per_chunk - 1) / obj_per_chunk; > > - table->icm = kcalloc(num_icm, sizeof(*table->icm), GFP_KERNEL); > + table->icm = vzalloc(num_icm * sizeof(*table->icm)); > if (!table->icm) > return -ENOMEM; > table->virt = virt; > @@ -446,7 +446,7 @@ int mlx4_init_icm_table(struct mlx4_dev *dev, struct > mlx4_icm_table *table, > mlx4_free_icm(dev, table->icm[i], use_coherent); > } > > - kfree(table->icm); > + vfree(table->icm); > > return -ENOMEM; > } > @@ -462,5 +462,5 @@ void mlx4_cleanup_icm_table(struct mlx4_dev *dev, struct > mlx4_icm_table *table) > mlx4_free_icm(dev, table->icm[i], table->coherent); > } > > - kfree(table->icm); > + vfree(table->icm); > } > -- > 2.9.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] mlx4_core: allocate 4KB ICM chunks
Thank you for reviewing it! On 5/10/2018 6:23 PM, Yanjun Zhu wrote: On 2018/5/11 9:15, Qing Huang wrote: On 5/10/2018 5:13 PM, Yanjun Zhu wrote: On 2018/5/11 7:31, Qing Huang wrote: When a system is under memory presure (high usage with fragments), the original 256KB ICM chunk allocations will likely trigger kernel memory management to enter slow path doing memory compact/migration ops in order to complete high order memory allocations. When that happens, user processes calling uverb APIs may get stuck for more than 120s easily even though there are a lot of free pages in smaller chunks available in the system. Syslog: ... Dec 10 09:04:51 slcc03db02 kernel: [397078.572732] INFO: task oracle_205573_e:205573 blocked for more than 120 seconds. ... With 4KB ICM chunk size, the above issue is fixed. However in order to support 4KB ICM chunk size, we need to fix another issue in large size kcalloc allocations. E.g. Setting log_num_mtt=30 requires 1G mtt entries. With the 4KB ICM chunk size, each ICM chunk can only hold 512 mtt entries (8 bytes for each mtt entry). So we need a 16MB allocation for a table->icm pointer array to hold 2M pointers which can easily cause kcalloc to fail. The solution is to use vzalloc to replace kcalloc. There is no need for contiguous memory pages for a driver meta data structure (no need Hi, Replace continuous memory pages with virtual memory, is there any performance loss? Not really. "table->icm" will be accessed as individual pointer variables randomly. Kcalloc Sure. Thanks. If "table->icm" will be accessed as individual pointer variables randomly, the performance loss caused by discontinuous memory will be very trivial. Reviewed-by: Zhu Yanjunalso returns a virtual address except its mapped pages are guaranteed to be contiguous which will provide little advantage over vzalloc for individual pointer variable access. Qing Zhu Yanjun of DMA ops). Signed-off-by: Qing Huang Acked-by: Daniel Jurgens --- drivers/net/ethernet/mellanox/mlx4/icm.c | 14 +++--- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/icm.c b/drivers/net/ethernet/mellanox/mlx4/icm.c index a822f7a..2b17a4b 100644 --- a/drivers/net/ethernet/mellanox/mlx4/icm.c +++ b/drivers/net/ethernet/mellanox/mlx4/icm.c @@ -43,12 +43,12 @@ #include "fw.h" /* - * We allocate in as big chunks as we can, up to a maximum of 256 KB - * per chunk. + * We allocate in 4KB page size chunks to avoid high order memory + * allocations in fragmented/high usage memory situation. */ enum { - MLX4_ICM_ALLOC_SIZE = 1 << 18, - MLX4_TABLE_CHUNK_SIZE = 1 << 18 + MLX4_ICM_ALLOC_SIZE = 1 << 12, + MLX4_TABLE_CHUNK_SIZE = 1 << 12 }; static void mlx4_free_icm_pages(struct mlx4_dev *dev, struct mlx4_icm_chunk *chunk) @@ -400,7 +400,7 @@ int mlx4_init_icm_table(struct mlx4_dev *dev, struct mlx4_icm_table *table, obj_per_chunk = MLX4_TABLE_CHUNK_SIZE / obj_size; num_icm = (nobj + obj_per_chunk - 1) / obj_per_chunk; - table->icm = kcalloc(num_icm, sizeof(*table->icm), GFP_KERNEL); + table->icm = vzalloc(num_icm * sizeof(*table->icm)); if (!table->icm) return -ENOMEM; table->virt = virt; @@ -446,7 +446,7 @@ int mlx4_init_icm_table(struct mlx4_dev *dev, struct mlx4_icm_table *table, mlx4_free_icm(dev, table->icm[i], use_coherent); } - kfree(table->icm); + vfree(table->icm); return -ENOMEM; } @@ -462,5 +462,5 @@ void mlx4_cleanup_icm_table(struct mlx4_dev *dev, struct mlx4_icm_table *table) mlx4_free_icm(dev, table->icm[i], table->coherent); } - kfree(table->icm); + vfree(table->icm); }
Re: [PATCH] mlx4_core: allocate 4KB ICM chunks
On 2018/5/11 7:31, Qing Huang wrote: When a system is under memory presure (high usage with fragments), the original 256KB ICM chunk allocations will likely trigger kernel memory management to enter slow path doing memory compact/migration ops in order to complete high order memory allocations. When that happens, user processes calling uverb APIs may get stuck for more than 120s easily even though there are a lot of free pages in smaller chunks available in the system. Syslog: ... Dec 10 09:04:51 slcc03db02 kernel: [397078.572732] INFO: task oracle_205573_e:205573 blocked for more than 120 seconds. ... With 4KB ICM chunk size, the above issue is fixed. However in order to support 4KB ICM chunk size, we need to fix another issue in large size kcalloc allocations. E.g. Setting log_num_mtt=30 requires 1G mtt entries. With the 4KB ICM chunk size, each ICM chunk can only hold 512 mtt entries (8 bytes for each mtt entry). So we need a 16MB allocation for a table->icm pointer array to hold 2M pointers which can easily cause kcalloc to fail. The solution is to use vzalloc to replace kcalloc. There is no need for contiguous memory pages for a driver meta data structure (no need Hi, Replace continuous memory pages with virtual memory, is there any performance loss? Zhu Yanjun of DMA ops). Signed-off-by: Qing HuangAcked-by: Daniel Jurgens --- drivers/net/ethernet/mellanox/mlx4/icm.c | 14 +++--- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/icm.c b/drivers/net/ethernet/mellanox/mlx4/icm.c index a822f7a..2b17a4b 100644 --- a/drivers/net/ethernet/mellanox/mlx4/icm.c +++ b/drivers/net/ethernet/mellanox/mlx4/icm.c @@ -43,12 +43,12 @@ #include "fw.h" /* - * We allocate in as big chunks as we can, up to a maximum of 256 KB - * per chunk. + * We allocate in 4KB page size chunks to avoid high order memory + * allocations in fragmented/high usage memory situation. */ enum { - MLX4_ICM_ALLOC_SIZE = 1 << 18, - MLX4_TABLE_CHUNK_SIZE = 1 << 18 + MLX4_ICM_ALLOC_SIZE = 1 << 12, + MLX4_TABLE_CHUNK_SIZE = 1 << 12 }; static void mlx4_free_icm_pages(struct mlx4_dev *dev, struct mlx4_icm_chunk *chunk) @@ -400,7 +400,7 @@ int mlx4_init_icm_table(struct mlx4_dev *dev, struct mlx4_icm_table *table, obj_per_chunk = MLX4_TABLE_CHUNK_SIZE / obj_size; num_icm = (nobj + obj_per_chunk - 1) / obj_per_chunk; - table->icm = kcalloc(num_icm, sizeof(*table->icm), GFP_KERNEL); + table->icm = vzalloc(num_icm * sizeof(*table->icm)); if (!table->icm) return -ENOMEM; table->virt = virt; @@ -446,7 +446,7 @@ int mlx4_init_icm_table(struct mlx4_dev *dev, struct mlx4_icm_table *table, mlx4_free_icm(dev, table->icm[i], use_coherent); } - kfree(table->icm); + vfree(table->icm); return -ENOMEM; } @@ -462,5 +462,5 @@ void mlx4_cleanup_icm_table(struct mlx4_dev *dev, struct mlx4_icm_table *table) mlx4_free_icm(dev, table->icm[i], table->coherent); } - kfree(table->icm); + vfree(table->icm); }
[PATCH] mlx4_core: allocate 4KB ICM chunks
When a system is under memory presure (high usage with fragments), the original 256KB ICM chunk allocations will likely trigger kernel memory management to enter slow path doing memory compact/migration ops in order to complete high order memory allocations. When that happens, user processes calling uverb APIs may get stuck for more than 120s easily even though there are a lot of free pages in smaller chunks available in the system. Syslog: ... Dec 10 09:04:51 slcc03db02 kernel: [397078.572732] INFO: task oracle_205573_e:205573 blocked for more than 120 seconds. ... With 4KB ICM chunk size, the above issue is fixed. However in order to support 4KB ICM chunk size, we need to fix another issue in large size kcalloc allocations. E.g. Setting log_num_mtt=30 requires 1G mtt entries. With the 4KB ICM chunk size, each ICM chunk can only hold 512 mtt entries (8 bytes for each mtt entry). So we need a 16MB allocation for a table->icm pointer array to hold 2M pointers which can easily cause kcalloc to fail. The solution is to use vzalloc to replace kcalloc. There is no need for contiguous memory pages for a driver meta data structure (no need of DMA ops). Signed-off-by: Qing HuangAcked-by: Daniel Jurgens --- drivers/net/ethernet/mellanox/mlx4/icm.c | 14 +++--- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/icm.c b/drivers/net/ethernet/mellanox/mlx4/icm.c index a822f7a..2b17a4b 100644 --- a/drivers/net/ethernet/mellanox/mlx4/icm.c +++ b/drivers/net/ethernet/mellanox/mlx4/icm.c @@ -43,12 +43,12 @@ #include "fw.h" /* - * We allocate in as big chunks as we can, up to a maximum of 256 KB - * per chunk. + * We allocate in 4KB page size chunks to avoid high order memory + * allocations in fragmented/high usage memory situation. */ enum { - MLX4_ICM_ALLOC_SIZE = 1 << 18, - MLX4_TABLE_CHUNK_SIZE = 1 << 18 + MLX4_ICM_ALLOC_SIZE = 1 << 12, + MLX4_TABLE_CHUNK_SIZE = 1 << 12 }; static void mlx4_free_icm_pages(struct mlx4_dev *dev, struct mlx4_icm_chunk *chunk) @@ -400,7 +400,7 @@ int mlx4_init_icm_table(struct mlx4_dev *dev, struct mlx4_icm_table *table, obj_per_chunk = MLX4_TABLE_CHUNK_SIZE / obj_size; num_icm = (nobj + obj_per_chunk - 1) / obj_per_chunk; - table->icm = kcalloc(num_icm, sizeof(*table->icm), GFP_KERNEL); + table->icm = vzalloc(num_icm * sizeof(*table->icm)); if (!table->icm) return -ENOMEM; table->virt = virt; @@ -446,7 +446,7 @@ int mlx4_init_icm_table(struct mlx4_dev *dev, struct mlx4_icm_table *table, mlx4_free_icm(dev, table->icm[i], use_coherent); } - kfree(table->icm); + vfree(table->icm); return -ENOMEM; } @@ -462,5 +462,5 @@ void mlx4_cleanup_icm_table(struct mlx4_dev *dev, struct mlx4_icm_table *table) mlx4_free_icm(dev, table->icm[i], table->coherent); } - kfree(table->icm); + vfree(table->icm); } -- 2.9.3