| Message ID | 1600828257-31316-1-git-send-email-chenhc@lemote.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/3] MIPS: Crash kernel should be able to see old memories | expand |
On 09/23/20 at 10:30am, Huacai Chen wrote: > Kexec-tools use mem=X@Y to pass usable memories to crash kernel, but in > commit a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") all > BIOS passed memories are removed by early_parse_mem(). I think this is > reasonable for a normal kernel but not for a crash kernel, because a > crash kernel should be able to see all old memories, even though it is > not supposed to use them. I am not familiar with MIPS code, but we analyze and fill memmap= to pass usable memory to crashkenrel in kexec-tools, do you mean you are specifying memmap= or mem= by hand? And we don't have mem=X@Y, only mem=nn[KMG]. > > Fixes: a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") > Signed-off-by: Huacai Chen <chenhc@lemote.com> > --- > arch/mips/kernel/setup.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c > index 4c04a86..e2804a2 100644 > --- a/arch/mips/kernel/setup.c > +++ b/arch/mips/kernel/setup.c > @@ -392,8 +392,10 @@ static int __init early_parse_mem(char *p) > */ > if (usermem == 0) { > usermem = 1; > +#ifndef CONFIG_CRASH_DUMP > memblock_remove(memblock_start_of_DRAM(), > memblock_end_of_DRAM() - memblock_start_of_DRAM()); > +#endif > } > start = 0; > size = memparse(p, &p); > -- > 2.7.0 >
Hi, Baoquan, On Wed, Sep 23, 2020 at 10:46 AM Baoquan He <bhe@redhat.com> wrote: > > On 09/23/20 at 10:30am, Huacai Chen wrote: > > Kexec-tools use mem=X@Y to pass usable memories to crash kernel, but in > > commit a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") all > > BIOS passed memories are removed by early_parse_mem(). I think this is > > reasonable for a normal kernel but not for a crash kernel, because a > > crash kernel should be able to see all old memories, even though it is > > not supposed to use them. > > I am not familiar with MIPS code, but we analyze and fill memmap= to > pass usable memory to crashkenrel in kexec-tools, do you mean you are > specifying memmap= or mem= by hand? Not by hand, but by code of kexec-tools via the "mem=" parameter. As I know, kexec-tools of MIPS only use "mem=" to pass "usable" memory, but not "visible" memory. "Visible" memory of the crash kernel is still passed by BIOS (strictly, by the old kernel who duplicates information from BIOS). If memblock_remove() executed here, it would remove all "visible" memory and make "visible" memory the same as "usable" memory, and I think this is not correct. > > And we don't have mem=X@Y, only mem=nn[KMG]. The relocatable kernel of MIPS is still unusable now, so MIPS should use mem=X@Y, and the crash kernel is always different from normal kernel. Huacai > > > > > Fixes: a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") > > Signed-off-by: Huacai Chen <chenhc@lemote.com> > > --- > > arch/mips/kernel/setup.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c > > index 4c04a86..e2804a2 100644 > > --- a/arch/mips/kernel/setup.c > > +++ b/arch/mips/kernel/setup.c > > @@ -392,8 +392,10 @@ static int __init early_parse_mem(char *p) > > */ > > if (usermem == 0) { > > usermem = 1; > > +#ifndef CONFIG_CRASH_DUMP > > memblock_remove(memblock_start_of_DRAM(), > > memblock_end_of_DRAM() - memblock_start_of_DRAM()); > > +#endif > > } > > start = 0; > > size = memparse(p, &p); > > -- > > 2.7.0 > > >
On 09/23/2020 10:30 AM, Huacai Chen wrote: > Kexec-tools use mem=X@Y to pass usable memories to crash kernel, but in > commit a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") all > BIOS passed memories are removed by early_parse_mem(). I think this is > reasonable for a normal kernel but not for a crash kernel, because a > crash kernel should be able to see all old memories, even though it is > not supposed to use them. > > Fixes: a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") > Signed-off-by: Huacai Chen <chenhc@lemote.com> > --- > arch/mips/kernel/setup.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c > index 4c04a86..e2804a2 100644 > --- a/arch/mips/kernel/setup.c > +++ b/arch/mips/kernel/setup.c > @@ -392,8 +392,10 @@ static int __init early_parse_mem(char *p) > */ > if (usermem == 0) { > usermem = 1; > +#ifndef CONFIG_CRASH_DUMP > memblock_remove(memblock_start_of_DRAM(), > memblock_end_of_DRAM() - memblock_start_of_DRAM()); > +#endif Hi, Huacai, For this patch, I knew something what had happened. "mem=" parsing works wrong for Loongson64. You can referenced the follow patch: https://patchwork.kernel.org/patch/11789555/ memblock_add() calls memblock_add_range(,,, MAX_NUMNODES,) For Loongson64 enabling NUMA, we need memblock_add_node(). (Or using memblock_set_node() after memblock_add()) Besides, "mem=" may be useless for kdump. Youling had submitted a patch about removing "mem=" serveral days ago. For Loongson64 platform, you can try crashkernel=SIZE@38M after fixed "mem=". 38M means 40M - 2M, 2M is needed because old firmware compatibility. Thanks, - Jinyang. > } > start = 0; > size = memparse(p, &p);
On 09/23/20 at 10:58am, Huacai Chen wrote: > Hi, Baoquan, > > On Wed, Sep 23, 2020 at 10:46 AM Baoquan He <bhe@redhat.com> wrote: > > > > On 09/23/20 at 10:30am, Huacai Chen wrote: > > > Kexec-tools use mem=X@Y to pass usable memories to crash kernel, but in > > > commit a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") all > > > BIOS passed memories are removed by early_parse_mem(). I think this is > > > reasonable for a normal kernel but not for a crash kernel, because a > > > crash kernel should be able to see all old memories, even though it is > > > not supposed to use them. > > > > I am not familiar with MIPS code, but we analyze and fill memmap= to > > pass usable memory to crashkenrel in kexec-tools, do you mean you are > > specifying memmap= or mem= by hand? > Not by hand, but by code of kexec-tools via the "mem=" parameter. OK, please ignore my comments. > > As I know, kexec-tools of MIPS only use "mem=" to pass "usable" > memory, but not "visible" memory. "Visible" memory of the crash kernel > is still passed by BIOS (strictly, by the old kernel who duplicates > information from BIOS). If memblock_remove() executed here, it would > remove all "visible" memory and make "visible" memory the same as > "usable" memory, and I think this is not correct. > > > > > And we don't have mem=X@Y, only mem=nn[KMG]. > The relocatable kernel of MIPS is still unusable now, so MIPS should > use mem=X@Y, and the crash kernel is always different from normal > kernel. Interesting. Seems MIPS does support mem=X@Y, even though the document of 'mem=' says it's used to specify amount of memory, but not memory region. Anyway, leave this to mips reviewers, thanks for replying. ~~~~~~~~~~~~~~~~~~~ mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory Amount of memory to be used in cases as follows: > > > > > > > > > Fixes: a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") > > > Signed-off-by: Huacai Chen <chenhc@lemote.com> > > > --- > > > arch/mips/kernel/setup.c | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c > > > index 4c04a86..e2804a2 100644 > > > --- a/arch/mips/kernel/setup.c > > > +++ b/arch/mips/kernel/setup.c > > > @@ -392,8 +392,10 @@ static int __init early_parse_mem(char *p) > > > */ > > > if (usermem == 0) { > > > usermem = 1; > > > +#ifndef CONFIG_CRASH_DUMP > > > memblock_remove(memblock_start_of_DRAM(), > > > memblock_end_of_DRAM() - memblock_start_of_DRAM()); > > > +#endif > > > } > > > start = 0; > > > size = memparse(p, &p); > > > -- > > > 2.7.0 > > > > > >
Hi, Jinyang, On Wed, Sep 23, 2020 at 11:02 AM Jinyang He <hejinyang@loongson.cn> wrote: > > On 09/23/2020 10:30 AM, Huacai Chen wrote: > > Kexec-tools use mem=X@Y to pass usable memories to crash kernel, but in > > commit a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") all > > BIOS passed memories are removed by early_parse_mem(). I think this is > > reasonable for a normal kernel but not for a crash kernel, because a > > crash kernel should be able to see all old memories, even though it is > > not supposed to use them. > > > > Fixes: a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") > > Signed-off-by: Huacai Chen <chenhc@lemote.com> > > --- > > arch/mips/kernel/setup.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c > > index 4c04a86..e2804a2 100644 > > --- a/arch/mips/kernel/setup.c > > +++ b/arch/mips/kernel/setup.c > > @@ -392,8 +392,10 @@ static int __init early_parse_mem(char *p) > > */ > > if (usermem == 0) { > > usermem = 1; > > +#ifndef CONFIG_CRASH_DUMP > > memblock_remove(memblock_start_of_DRAM(), > > memblock_end_of_DRAM() - memblock_start_of_DRAM()); > > +#endif > > Hi, Huacai, > > For this patch, I knew something what had happened. "mem=" parsing > works wrong for Loongson64. You can referenced the follow patch: > https://patchwork.kernel.org/patch/11789555/ > > memblock_add() calls memblock_add_range(,,, MAX_NUMNODES,) > For Loongson64 enabling NUMA, we need memblock_add_node(). (Or > using memblock_set_node() after memblock_add()) This seems like another story. > > Besides, "mem=" may be useless for kdump. Youling had submitted a patch > about removing "mem=" serveral days ago. kexec-tools use "mem=" to pass usable memory for the crash kernel, Youling removes the base address of "mem=", but "mem=" is still here. > > For Loongson64 platform, you can try crashkernel=SIZE@38M after fixed > "mem=". > 38M means 40M - 2M, 2M is needed because old firmware compatibility. "crashkernel=" is for the normal kernel specified by BIOS, and "mem=" is for the crash kernel specified by kexec-tools. Huacai > > Thanks, > - Jinyang. > > > } > > start = 0; > > size = memparse(p, &p); >
On Wed, 23 Sep 2020, Baoquan He wrote: > > > And we don't have mem=X@Y, only mem=nn[KMG]. > > The relocatable kernel of MIPS is still unusable now, so MIPS should > > use mem=X@Y, and the crash kernel is always different from normal > > kernel. > > Interesting. Seems MIPS does support mem=X@Y, even though the document > of 'mem=' says it's used to specify amount of memory, but not memory > region. Anyway, leave this to mips reviewers, thanks for replying. > > ~~~~~~~~~~~~~~~~~~~ > mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory > Amount of memory to be used in cases as follows: Yep, I implemented it for the DECstation back in 2000: commit 97b7ae4257ef7ba8ed9b7944a4f56a49af3e8abb Author: Ralf Baechle <ralf@linux-mips.org> Date: Mon Dec 11 16:41:05 2000 +0000 Memmap fixes from Maciej. (from the LMO repo) in line with the x86 syntax. I don't know why it hasn't ever been documented in "Kernel Parameters" (for any port), but I'm fairly sure it has been somewhere. FWIW, Maciej
On Sat, 3 Oct 2020, Maciej W. Rozycki wrote: > > Interesting. Seems MIPS does support mem=X@Y, even though the document > > of 'mem=' says it's used to specify amount of memory, but not memory > > region. Anyway, leave this to mips reviewers, thanks for replying. > > > > ~~~~~~~~~~~~~~~~~~~ > > mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory > > Amount of memory to be used in cases as follows: > > Yep, I implemented it for the DECstation back in 2000: > > commit 97b7ae4257ef7ba8ed9b7944a4f56a49af3e8abb > Author: Ralf Baechle <ralf@linux-mips.org> > Date: Mon Dec 11 16:41:05 2000 +0000 > > Memmap fixes from Maciej. > > (from the LMO repo) in line with the x86 syntax. I don't know why it > hasn't ever been documented in "Kernel Parameters" (for any port), but I'm > fairly sure it has been somewhere. Self-correction: documentation used to be there, but was removed around Linux 2.5.65: commit 041a679cb20e4fcb841665b09cf7c6d24ab4ad39 Author: Ralf Baechle <ralf@linux-mips.org> Date: Thu Jun 5 00:04:28 2003 +0000 Merge with Linux 2.5.65. (same repo) as the parameter was renamed to `memmap=' in the x86 port. Obviously whoever did that did not bother to check other ports, even though the parameter was marked (and `memmap=' still is) generic. Maciej
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index 4c04a86..e2804a2 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -392,8 +392,10 @@ static int __init early_parse_mem(char *p) */ if (usermem == 0) { usermem = 1; +#ifndef CONFIG_CRASH_DUMP memblock_remove(memblock_start_of_DRAM(), memblock_end_of_DRAM() - memblock_start_of_DRAM()); +#endif } start = 0; size = memparse(p, &p);
Kexec-tools use mem=X@Y to pass usable memories to crash kernel, but in commit a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") all BIOS passed memories are removed by early_parse_mem(). I think this is reasonable for a normal kernel but not for a crash kernel, because a crash kernel should be able to see all old memories, even though it is not supposed to use them. Fixes: a94e4f24ec836c8984f83959 ("MIPS: init: Drop boot_mem_map") Signed-off-by: Huacai Chen <chenhc@lemote.com> --- arch/mips/kernel/setup.c | 2 ++ 1 file changed, 2 insertions(+)