lkml.org 
[lkml]   [2021]   [Jan]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 1/4] RISC-V: Do not allocate memblock while iterating reserved memblocks
On Thu, Jan 7, 2021 at 2:57 PM Atish Patra <atish.patra@wdc.com> wrote:
>
> Currently, resource tree allocates memory blocks while iterating on the
> list. It leads to following kernel warning because memblock allocation
> also invokes memory block reservation API.
>
> [ 0.000000] ------------[ cut here ]------------
> [ 0.000000] WARNING: CPU: 0 PID: 0 at kernel/resource.c:795
> __insert_resource+0x8e/0xd0
> [ 0.000000] Modules linked in:
> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted
> 5.10.0-00022-ge20097fb37e2-dirty #549
> [ 0.000000] epc: c00125c2 ra : c001262c sp : c1c01f50
> [ 0.000000] gp : c1d456e0 tp : c1c0a980 t0 : ffffcf20
> [ 0.000000] t1 : 00000000 t2 : 00000000 s0 : c1c01f60
> [ 0.000000] s1 : ffffcf00 a0 : ffffff00 a1 : c1c0c0c4
> [ 0.000000] a2 : 80c12b15 a3 : 80402000 a4 : 80402000
> [ 0.000000] a5 : c1c0c0c4 a6 : 80c12b15 a7 : f5faf600
> [ 0.000000] s2 : c1c0c0c4 s3 : c1c0e000 s4 : c1009a80
> [ 0.000000] s5 : c1c0c000 s6 : c1d48000 s7 : c1613b4c
> [ 0.000000] s8 : 00000fff s9 : 80000200 s10: c1613b40
> [ 0.000000] s11: 00000000 t3 : c1d4a000 t4 : ffffffff
>
> This is also unnecessary as we can pre-compute the total memblocks required
> for each memory region and allocate it before the loop. It save precious
> boot time not going through memblock allocation code every time.
>
> Fixes: 00ab027a3b82 ("RISC-V: Add kernel image sections to the resource tree")
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>

Looks good to me.

Reviewed-by: Anup Patel <anup@brainfault.org>

> ---
> arch/riscv/kernel/setup.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> index 1d85e9bf783c..3fa3f26dde85 100644
> --- a/arch/riscv/kernel/setup.c
> +++ b/arch/riscv/kernel/setup.c
> @@ -127,7 +127,9 @@ static void __init init_resources(void)
> {
> struct memblock_region *region = NULL;
> struct resource *res = NULL;
> - int ret = 0;
> + struct resource *mem_res = NULL;
> + size_t mem_res_sz = 0;
> + int ret = 0, i = 0;
>
> code_res.start = __pa_symbol(_text);
> code_res.end = __pa_symbol(_etext) - 1;
> @@ -145,16 +147,17 @@ static void __init init_resources(void)
> bss_res.end = __pa_symbol(__bss_stop) - 1;
> bss_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
>
> + mem_res_sz = (memblock.memory.cnt + memblock.reserved.cnt) * sizeof(*mem_res);
> + mem_res = memblock_alloc(mem_res_sz, SMP_CACHE_BYTES);
> + if (!mem_res)
> + panic("%s: Failed to allocate %zu bytes\n", __func__, mem_res_sz);
> /*
> * Start by adding the reserved regions, if they overlap
> * with /memory regions, insert_resource later on will take
> * care of it.
> */
> for_each_reserved_mem_region(region) {
> - res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
> - if (!res)
> - panic("%s: Failed to allocate %zu bytes\n", __func__,
> - sizeof(struct resource));
> + res = &mem_res[i++];
>
> res->name = "Reserved";
> res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> @@ -171,8 +174,10 @@ static void __init init_resources(void)
> * Ignore any other reserved regions within
> * system memory.
> */
> - if (memblock_is_memory(res->start))
> + if (memblock_is_memory(res->start)) {
> + memblock_free((phys_addr_t) res, sizeof(struct resource));
> continue;
> + }
>
> ret = add_resource(&iomem_resource, res);
> if (ret < 0)
> @@ -181,10 +186,7 @@ static void __init init_resources(void)
>
> /* Add /memory regions to the resource tree */
> for_each_mem_region(region) {
> - res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
> - if (!res)
> - panic("%s: Failed to allocate %zu bytes\n", __func__,
> - sizeof(struct resource));
> + res = &mem_res[i++];
>
> if (unlikely(memblock_is_nomap(region))) {
> res->name = "Reserved";
> @@ -205,9 +207,9 @@ static void __init init_resources(void)
> return;
>
> error:
> - memblock_free((phys_addr_t) res, sizeof(struct resource));
> /* Better an empty resource tree than an inconsistent one */
> release_child_resources(&iomem_resource);
> + memblock_free((phys_addr_t) mem_res, mem_res_sz);
> }
>
>
> --
> 2.25.1
>
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

Regards,
Anup

\
 
 \ /
  Last update: 2021-01-11 04:56    [W:0.111 / U:3.316 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site