Re: [Crash-utility] [PATCH] Update for the "kmem -n" option on Linux 5.3-rc1 and later kernels

Hi Kazu, Do you have a sample 5.3-rc1 vmlinux/vmcore pair that I can test this with? You can send it to me offline. Thanks, Dave ----- Original Message ----- > Update for the "kmem -n" option on Linux 5.3-rc1 and later kernels that > contain commit 326e1b8f83a4318b09033ef754f40c785aed5e68, titled > "mm/sparsemem: introduce a SECTION_IS_EARLY flag". With this patch, > the option displays a new state "E" for the flag, instead of printing > incorrect mem_map addresses. > > Also update the confusing comment with the one from kernel commit > def9b71ee651a6fee93a10734b94f93a69cdb2d4, titled "include/linux/mmzone.h: > fix explanation of lower bits in the SPARSEMEM mem_map pointer". > > Signed-off-by: Kazuhito Hagio <k-hagio(a)ab.jp.nec.com&gt; > --- > help.c | 4 ++-- > memory.c | 17 ++++++++++++++--- > 2 files changed, 16 insertions(+), 5 deletions(-) > > diff --git a/help.c b/help.c > index d5940f789ffd..a5218a701c01 100644 > --- a/help.c > +++ b/help.c > @@ -6597,8 +6597,8 @@ char *help_kmem[] = { > " the cumulative, vm_event_states counter values if they > exist.", > " -n display memory node, memory section, and memory block data", > " and state; the state of each memory section state is > encoded", > -" as \"P\", \"M\" and/or \"O\", meaning > SECTION_MARKED_PRESENT,", > -" SECTION_HAS_MEM_MAP and SECTION_IS_ONLINE.", > +" as \"P\", \"M\", \"O\" and/or \"E\", meaning > SECTION_MARKED_PRESENT,", > +" SECTION_HAS_MEM_MAP, SECTION_IS_ONLINE and > SECTION_IS_EARLY.", > " -z displays per-zone memory statistics.", > " -o displays each cpu's offset value that is added to per-cpu > symbol", > " values to translate them into kernel virtual addresses.", > diff --git a/memory.c b/memory.c > index 327e5355ec9c..ac7e73679405 100644 > --- a/memory.c > +++ b/memory.c > @@ -17154,13 +17154,22 @@ nr_to_section(ulong nr) > > /* > * We use the lower bits of the mem_map pointer to store > - * a little bit of information. There should be at least > - * 3 bits here due to 32-bit alignment. > + * a little bit of information. The pointer is calculated > + * as mem_map - section_nr_to_pfn(pnum). The result is > + * aligned to the minimum alignment of the two values: > + * 1. All mem_map arrays are page-aligned. > + * 2. section_nr_to_pfn() always clears PFN_SECTION_SHIFT > + * lowest bits. PFN_SECTION_SHIFT is arch-specific > + * (equal SECTION_SIZE_BITS - PAGE_SHIFT), and the > + * worst combination is powerpc with 256k pages, > + * which results in PFN_SECTION_SHIFT equal 6. > + * To sum it up, at least 6 bits are available. > */ > #define SECTION_MARKED_PRESENT (1UL<<0) > #define SECTION_HAS_MEM_MAP (1UL<<1) > #define SECTION_IS_ONLINE (1UL<<2) > -#define SECTION_MAP_LAST_BIT (1UL<<3) > +#define SECTION_IS_EARLY (1UL<<3) > +#define SECTION_MAP_LAST_BIT (1UL<<4) > #define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1)) > > > @@ -17257,6 +17266,8 @@ fill_mem_section_state(ulong state, char *buf) > bufidx += sprintf(buf + bufidx, "%s", "M"); > if (state & SECTION_IS_ONLINE) > bufidx += sprintf(buf + bufidx, "%s", "O"); > + if (state & SECTION_IS_EARLY) > + bufidx += sprintf(buf + bufidx, "%s", "E"); > } > > void > -- > 2.18.1 > > -- > Crash-utility mailing list > Crash-utility(a)redhat.com > https://www.redhat.com/mailman/listinfo/crash-utility > -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility