| Message ID | 1645707132-10121-1-git-send-email-yangtiezhu@loongson.cn (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | MIPS: Refactor early_parse_mem() to fix mem= parameter | expand |
Hi, Tiezhu On 02/24/2022 08:52 PM, Tiezhu Yang wrote: > According to Documentation/admin-guide/kernel-parameters.txt, > the kernel command-line parameter mem= means "Force usage of > a specific amount of memory", but when add "mem=3G" to the > command-line, kernel boot hangs in sparse_init(). > > This commit is similar with the implementation of the other > archs such as arm64, powerpc and riscv, refactor the function > early_parse_mem() and then use memblock_enforce_memory_limit() > to limit the memory size. > > With this patch, when add "mem=3G" to the command-line, the > kernel boots successfully, we can see the following messages: > > [ 0.000000] Memory limited to 3072MB > ... > [ 0.000000] Memory: 2991952K/3145728K available (...) > > After login, the output of free command is consistent with the > above log. > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> > --- > arch/mips/kernel/setup.c | 25 ++++++++----------------- > 1 file changed, 8 insertions(+), 17 deletions(-) > > diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c > index f979adf..2917412 100644 > --- a/arch/mips/kernel/setup.c > +++ b/arch/mips/kernel/setup.c > @@ -339,27 +339,15 @@ static void __init bootmem_init(void) > #endif /* CONFIG_SGI_IP27 */ > > static int usermem __initdata; > +static phys_addr_t memory_limit; > > static int __init early_parse_mem(char *p) > { > - phys_addr_t start, size; > - > - /* > - * If a user specifies memory size, we > - * blow away any automatically generated > - * size. > - */ > - if (usermem == 0) { > - usermem = 1; > - memblock_remove(memblock_start_of_DRAM(), > - memblock_end_of_DRAM() - memblock_start_of_DRAM()); > - } > - start = 0; > - size = memparse(p, &p); > - if (*p == '@') > - start = memparse(p + 1, &p); > + if (!p) > + return 1; > > - memblock_add(start, size); > + memory_limit = memparse(p, &p) & PAGE_MASK; > + pr_notice("Memory limited to %lldMB\n", memory_limit >> 20); > > return 0; After applying this patch, my guess is that the kdump operation will fail. In the MIPS architecture, when the kdump operation is performed, a "mem=YM@XM" parameter will be added to the capture kernel (added by kexec-tools), indicating that the available memory range of the capture kernel is [X, X+Y). After the "mem" parameter is changed to the above, there will be only a similar parsing function like "mem=3G", and the type like "mem=128M@64M" cannot be correctly parsed. Thanks, Youling. > } > @@ -633,6 +621,9 @@ static void __init arch_mem_init(char **cmdline_p) > > parse_early_param(); > > + /* Limit the memory size via mem= command-line parameter */ > + memblock_enforce_memory_limit(memory_limit); > + > if (usermem) > pr_info("User-defined physical RAM map overwrite\n"); >
On 02/25/2022 09:12 AM, Youling Tang wrote: > Hi, Tiezhu > > On 02/24/2022 08:52 PM, Tiezhu Yang wrote: >> According to Documentation/admin-guide/kernel-parameters.txt, >> the kernel command-line parameter mem= means "Force usage of >> a specific amount of memory", but when add "mem=3G" to the >> command-line, kernel boot hangs in sparse_init(). >> >> This commit is similar with the implementation of the other >> archs such as arm64, powerpc and riscv, refactor the function >> early_parse_mem() and then use memblock_enforce_memory_limit() >> to limit the memory size. >> >> With this patch, when add "mem=3G" to the command-line, the >> kernel boots successfully, we can see the following messages: >> >> [ 0.000000] Memory limited to 3072MB >> ... >> [ 0.000000] Memory: 2991952K/3145728K available (...) >> >> After login, the output of free command is consistent with the >> above log. >> >> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> >> --- >> arch/mips/kernel/setup.c | 25 ++++++++----------------- >> 1 file changed, 8 insertions(+), 17 deletions(-) >> >> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c >> index f979adf..2917412 100644 >> --- a/arch/mips/kernel/setup.c >> +++ b/arch/mips/kernel/setup.c >> @@ -339,27 +339,15 @@ static void __init bootmem_init(void) >> #endif /* CONFIG_SGI_IP27 */ >> static int usermem __initdata; >> +static phys_addr_t memory_limit; >> static int __init early_parse_mem(char *p) >> { >> - phys_addr_t start, size; >> - >> - /* >> - * If a user specifies memory size, we >> - * blow away any automatically generated >> - * size. >> - */ >> - if (usermem == 0) { >> - usermem = 1; >> - memblock_remove(memblock_start_of_DRAM(), >> - memblock_end_of_DRAM() - memblock_start_of_DRAM()); >> - } >> - start = 0; >> - size = memparse(p, &p); >> - if (*p == '@') >> - start = memparse(p + 1, &p); >> + if (!p) >> + return 1; >> - memblock_add(start, size); >> + memory_limit = memparse(p, &p) & PAGE_MASK; >> + pr_notice("Memory limited to %lldMB\n", memory_limit >> 20); >> return 0; > > After applying this patch, my guess is that the kdump operation will fail. > > In the MIPS architecture, when the kdump operation is performed, a > "mem=YM@XM" parameter will be added to the capture kernel (added by > kexec-tools), indicating that the available memory range of the > capture kernel is [X, X+Y). > > After the "mem" parameter is changed to the above, there will be only > a similar parsing function like "mem=3G", and the type like > "mem=128M@64M" cannot be correctly parsed. Hi Youling, Don't worry, it is another issue, I will take that into account once this patch is applied. This commit is the first step to fix the issue about mem=limit, I think it is possible to support mem=limit@base and I will do that later. Thanks, Tiezhu > > Thanks, > Youling. >> } >> @@ -633,6 +621,9 @@ static void __init arch_mem_init(char **cmdline_p) >> parse_early_param(); >> + /* Limit the memory size via mem= command-line parameter */ >> + memblock_enforce_memory_limit(memory_limit); >> + >> if (usermem) >> pr_info("User-defined physical RAM map overwrite\n"); >>
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index f979adf..2917412 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -339,27 +339,15 @@ static void __init bootmem_init(void) #endif /* CONFIG_SGI_IP27 */ static int usermem __initdata; +static phys_addr_t memory_limit; static int __init early_parse_mem(char *p) { - phys_addr_t start, size; - - /* - * If a user specifies memory size, we - * blow away any automatically generated - * size. - */ - if (usermem == 0) { - usermem = 1; - memblock_remove(memblock_start_of_DRAM(), - memblock_end_of_DRAM() - memblock_start_of_DRAM()); - } - start = 0; - size = memparse(p, &p); - if (*p == '@') - start = memparse(p + 1, &p); + if (!p) + return 1; - memblock_add(start, size); + memory_limit = memparse(p, &p) & PAGE_MASK; + pr_notice("Memory limited to %lldMB\n", memory_limit >> 20); return 0; } @@ -633,6 +621,9 @@ static void __init arch_mem_init(char **cmdline_p) parse_early_param(); + /* Limit the memory size via mem= command-line parameter */ + memblock_enforce_memory_limit(memory_limit); + if (usermem) pr_info("User-defined physical RAM map overwrite\n");
According to Documentation/admin-guide/kernel-parameters.txt, the kernel command-line parameter mem= means "Force usage of a specific amount of memory", but when add "mem=3G" to the command-line, kernel boot hangs in sparse_init(). This commit is similar with the implementation of the other archs such as arm64, powerpc and riscv, refactor the function early_parse_mem() and then use memblock_enforce_memory_limit() to limit the memory size. With this patch, when add "mem=3G" to the command-line, the kernel boots successfully, we can see the following messages: [ 0.000000] Memory limited to 3072MB ... [ 0.000000] Memory: 2991952K/3145728K available (...) After login, the output of free command is consistent with the above log. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> --- arch/mips/kernel/setup.c | 25 ++++++++----------------- 1 file changed, 8 insertions(+), 17 deletions(-)