| Message ID | 1582121897-24336-1-git-send-email-kernelfans@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [PATCHv3] powerpc/crashkernel: take "mem=" option into account | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (65b2623f395a4e25ab3ff4cff1c9c7623619a22d) |
| snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64e | success | Build succeeded |
| snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
| snowpatch_ozlabs/checkpatch | warning | total: 0 errors, 1 warnings, 1 checks, 22 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
Hello Pingfan, Thanks for the patch.. On 19/02/20 7:48 PM, Pingfan Liu wrote: > 'mem=" option is an easy way to put high pressure on memory during some > test. Hence after applying the memory limit, instead of total mem, the > actual usable memory should be considered when reserving mem for > crashkernel. Otherwise the boot up may experience OOM issue. > > E.g. it would reserve 4G prior to the change and 512M afterward, if passing > crashkernel="2G-4G:384M,4G-16G:512M,16G-64G:1G,64G-128G:2G,128G-:4G", and > mem=5G on a 256G machine. > > This issue is powerpc specific because it puts higher priority on fadump > and kdump reservation than on "mem=". Referring the following code: > if (fadump_reserve_mem() == 0) > reserve_crashkernel(); > ... > /* Ensure that total memory size is page-aligned. */ > limit = ALIGN(memory_limit ?: memblock_phys_mem_size(), PAGE_SIZE); > memblock_enforce_memory_limit(limit); > > While on other arches, the effect of "mem=" takes a higher priority and pass > through memblock_phys_mem_size() before calling reserve_crashkernel(). > > Signed-off-by: Pingfan Liu <kernelfans@gmail.com> > To: linuxppc-dev@lists.ozlabs.org > Cc: Hari Bathini <hbathini@linux.ibm.com> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: kexec@lists.infradead.org > --- > v2 -> v3: improve commit log > arch/powerpc/kernel/machine_kexec.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c > index c4ed328..eec96dc 100644 > --- a/arch/powerpc/kernel/machine_kexec.c > +++ b/arch/powerpc/kernel/machine_kexec.c > @@ -114,11 +114,12 @@ void machine_kexec(struct kimage *image) > > void __init reserve_crashkernel(void) > { > - unsigned long long crash_size, crash_base; > + unsigned long long crash_size, crash_base, total_mem_sz; > int ret; > > + total_mem_sz = memory_limit ? memory_limit : memblock_phys_mem_size(); > /* use common parsing */ > - ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), > + ret = parse_crashkernel(boot_command_line, total_mem_sz, > &crash_size, &crash_base); > if (ret == 0 && crash_size > 0) { > crashk_res.start = crash_base; memory_limit is adjusted after this with the below snippet: /* Crash kernel trumps memory limit */ if (memory_limit && memory_limit <= crashk_res.end) { memory_limit = crashk_res.end + 1; printk("Adjusted memory limit for crashkernel, now 0x%llx\n", memory_limit); } So, either the above snippet must be dropped or the print below should use an updated total_mem_sz based on adjusted memory_limit. I would prefer the latter.. > @@ -185,7 +186,7 @@ void __init reserve_crashkernel(void) > "for crashkernel (System RAM: %ldMB)\n", > (unsigned long)(crash_size >> 20), > (unsigned long)(crashk_res.start >> 20), > - (unsigned long)(memblock_phys_mem_size() >> 20)); > + (unsigned long)(total_mem_sz >> 20)); > > if (!memblock_is_region_memory(crashk_res.start, crash_size) || > memblock_reserve(crashk_res.start, crash_size)) { >
diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c index c4ed328..eec96dc 100644 --- a/arch/powerpc/kernel/machine_kexec.c +++ b/arch/powerpc/kernel/machine_kexec.c @@ -114,11 +114,12 @@ void machine_kexec(struct kimage *image) void __init reserve_crashkernel(void) { - unsigned long long crash_size, crash_base; + unsigned long long crash_size, crash_base, total_mem_sz; int ret; + total_mem_sz = memory_limit ? memory_limit : memblock_phys_mem_size(); /* use common parsing */ - ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), + ret = parse_crashkernel(boot_command_line, total_mem_sz, &crash_size, &crash_base); if (ret == 0 && crash_size > 0) { crashk_res.start = crash_base; @@ -185,7 +186,7 @@ void __init reserve_crashkernel(void) "for crashkernel (System RAM: %ldMB)\n", (unsigned long)(crash_size >> 20), (unsigned long)(crashk_res.start >> 20), - (unsigned long)(memblock_phys_mem_size() >> 20)); + (unsigned long)(total_mem_sz >> 20)); if (!memblock_is_region_memory(crashk_res.start, crash_size) || memblock_reserve(crashk_res.start, crash_size)) {
'mem=" option is an easy way to put high pressure on memory during some test. Hence after applying the memory limit, instead of total mem, the actual usable memory should be considered when reserving mem for crashkernel. Otherwise the boot up may experience OOM issue. E.g. it would reserve 4G prior to the change and 512M afterward, if passing crashkernel="2G-4G:384M,4G-16G:512M,16G-64G:1G,64G-128G:2G,128G-:4G", and mem=5G on a 256G machine. This issue is powerpc specific because it puts higher priority on fadump and kdump reservation than on "mem=". Referring the following code: if (fadump_reserve_mem() == 0) reserve_crashkernel(); ... /* Ensure that total memory size is page-aligned. */ limit = ALIGN(memory_limit ?: memblock_phys_mem_size(), PAGE_SIZE); memblock_enforce_memory_limit(limit); While on other arches, the effect of "mem=" takes a higher priority and pass through memblock_phys_mem_size() before calling reserve_crashkernel(). Signed-off-by: Pingfan Liu <kernelfans@gmail.com> To: linuxppc-dev@lists.ozlabs.org Cc: Hari Bathini <hbathini@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: kexec@lists.infradead.org --- v2 -> v3: improve commit log arch/powerpc/kernel/machine_kexec.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)