[Crash-utility] [RFC PATCH 1/2] crash: Show memory overcommit data in dump_kmeminfo()
Dave Anderson
anderson at redhat.com
Fri Nov 21 17:06:03 UTC 2014
Aaron,
I like the addition. But I've got a few nits regarding the patch.
Given that "kmem -i" is so commonly-used, I prefer not to introduce something
that could conceivably generate a command-killing "invalid structure member
offset" error. And that could happen in your hugetlb_total_pages() function
because of the hstate structure dependencies. (See dump_hstates() for example)
Also, in dump_kmeminfo() you use MEMBER_OFFSET(), which should be avoided
because it will quietly return -1 if the structure member doesn't exist,
leading to bogus output. That's the whole purpose behind using OFFSET(),
or at least storing/validating the MEMBER_OFFSET() return value before
blindly using it.
It may seem pedantic, but if history has shown us anything, it's that
kernel developers cannot stop themselves from changing structure/member
names.
So if you could just adjust those kinds of issues, this patch would be
a nice addition.
Thanks,
Dave
----- Original Message -----
> This patch changes dump_kmeminfo() to report overcommit information similar
> to that displayed under the proc/meminfo file. It may be useful to indicate
> memory over commitment abuse, for example with forced vmcores from system
> hangs due to shortage of memory. The intended output is as follows:
>
> crash> kmem -i
> PAGES TOTAL PERCENTAGE
> TOTAL MEM 1965332 7.5 GB ----
> FREE 78080 305 MB 3% of TOTAL MEM
> USED 1887252 7.2 GB 96% of TOTAL MEM
> SHARED 789954 3 GB 40% of TOTAL MEM
> BUFFERS 110606 432.1 MB 5% of TOTAL MEM
> CACHED 1212645 4.6 GB 61% of TOTAL MEM
> SLAB 146563 572.5 MB 7% of TOTAL MEM
>
> TOTAL SWAP 1970175 7.5 GB ----
> SWAP USED 5 20 KB 0% of TOTAL SWAP
> SWAP FREE 1970170 7.5 GB 99% of TOTAL SWAP
>
> COMMIT LIMIT 2952841 11.3 GB ----
> COMMITTED 1150595 4.4 GB 38% of TOTAL LIMIT
>
> Tested under 3.16.4-200.fc20.x86_64 only.
> Though this should work under RHEL5 (2.6.18) and above.
>
> Signed-off-by: Aaron Tomlin <atomlin at redhat.com>
> Suggested-by: Alexis Solanas <alexis at redhat.com>
> ---
> help.c | 33 ++++++++--------
> memory.c | 132
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++--------
> 2 files changed, 134 insertions(+), 31 deletions(-)
>
> diff --git a/help.c b/help.c
> index 6aa3e20..bedd7c3 100644
> --- a/help.c
> +++ b/help.c
> @@ -5587,23 +5587,26 @@ char *help_kmem[] = {
> "\nEXAMPLES",
> " Display memory usage information:\n",
> " %s> kmem -i",
> -" PAGES TOTAL PERCENTAGE",
> -" TOTAL MEM 63602 248.4 MB ----",
> -" FREE 993 3.9 MB 1% of TOTAL MEM",
> -" USED 62609 244.6 MB 98% of TOTAL MEM",
> -" SHARED 34035 132.9 MB 53% of TOTAL MEM",
> -" BUFFERS 10928 42.7 MB 17% of TOTAL MEM",
> -" CACHED 35249 137.7 MB 55% of TOTAL MEM",
> -" SLAB 2823 11 MB 4% of TOTAL MEM",
> +" PAGES TOTAL PERCENTAGE",
> +" TOTAL MEM 63602 248.4 MB ----",
> +" FREE 993 3.9 MB 1% of TOTAL MEM",
> +" USED 62609 244.6 MB 98% of TOTAL MEM",
> +" SHARED 34035 132.9 MB 53% of TOTAL MEM",
> +" BUFFERS 10928 42.7 MB 17% of TOTAL MEM",
> +" CACHED 35249 137.7 MB 55% of TOTAL MEM",
> +" SLAB 2823 11 MB 4% of TOTAL MEM",
> " ",
> -" TOTAL HIGH 0 0 0% of TOTAL MEM",
> -" FREE HIGH 0 0 0% of TOTAL HIGH",
> -" TOTAL LOW 63602 248.4 MB 100% of TOTAL MEM",
> -" FREE LOW 993 3.9 MB 1% of TOTAL LOW",
> +" TOTAL HIGH 0 0 0% of TOTAL MEM",
> +" FREE HIGH 0 0 0% of TOTAL HIGH",
> +" TOTAL LOW 63602 248.4 MB 100% of TOTAL MEM",
> +" FREE LOW 993 3.9 MB 1% of TOTAL LOW",
> " ",
> -" TOTAL SWAP 129792 507 MB ----",
> -" SWAP USED 14727 57.5 MB 11% of TOTAL SWAP",
> -" SWAP FREE 115065 449.5 MB 88% of TOTAL SWAP",
> +" TOTAL SWAP 129792 507 MB ----",
> +" SWAP USED 14727 57.5 MB 11% of TOTAL SWAP",
> +" SWAP FREE 115065 449.5 MB 88% of TOTAL SWAP",
> +" ",
> +" COMMIT LIMIT 2952841 11.3 GB ----",
> +" COMMITTED 1158600 4.4 GB 39% of TOTAL LIMIT",
> " ",
> " ZONE NAME FREE ACTIVE INACTIVE_DIRTY INACTIVE_CLEAN
> MIN/LOW/HIGH",
> " 0 DMA 240 1166 7 161
> 128/256/384 ",
> diff --git a/memory.c b/memory.c
> index 3ac928d..823ec75 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -227,6 +227,7 @@ static int vm_area_page_dump(ulong, ulong, ulong, ulong,
> ulong,
> struct reference *);
> static void rss_page_types_init(void);
> static int dump_swap_info(ulong, ulong *, ulong *);
> +static ulong hugetlb_total_pages(void);
> static void swap_info_init(void);
> static char *get_swapdev(ulong, char *);
> static void fill_swap_info(ulong);
> @@ -4627,7 +4628,7 @@ cmd_kmem(void)
>
> }
>
> - if (iflag == 1)
> + if (iflag)
> dump_kmeminfo();
>
> if (pflag == 1)
> @@ -7653,7 +7654,7 @@ bailout:
> * by /proc/meminfo, and then some...
> */
>
> -char *kmeminfo_hdr = " PAGES TOTAL PERCENTAGE\n";
> +char *kmeminfo_hdr = " PAGES TOTAL
> PERCENTAGE\n";
>
> static void
> dump_kmeminfo(void)
> @@ -7670,6 +7671,10 @@ dump_kmeminfo(void)
> ulong freehighmem_pages;
> ulong totallowmem_pages;
> ulong freelowmem_pages;
> + ulong allowed;
> + long committed;
> + ulong overcommit_kbytes;
> + int overcommit_ratio;
> long nr_file_pages, nr_slab;
> ulong swapper_space_nrpages;
> ulong pct;
> @@ -7720,7 +7725,7 @@ dump_kmeminfo(void)
> } else
> totalram_pages = get_totalram;
>
> - fprintf(fp, "%10s %7ld %11s ----\n", "TOTAL MEM",
> + fprintf(fp, "%13s %7ld %11s ----\n", "TOTAL MEM",
> totalram_pages, pages_to_size(totalram_pages, buf));
>
> /*
> @@ -7731,12 +7736,12 @@ dump_kmeminfo(void)
> vt->dump_free_pages(&meminfo);
> freeram_pages = meminfo.retval;
> pct = (freeram_pages * 100)/totalram_pages;
> - fprintf(fp, "%10s %7ld %11s %3ld%% of TOTAL MEM\n",
> + fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL MEM\n",
> "FREE", freeram_pages, pages_to_size(freeram_pages, buf), pct);
>
> used_pages = totalram_pages - freeram_pages;
> pct = (used_pages * 100)/totalram_pages;
> - fprintf(fp, "%10s %7ld %11s %3ld%% of TOTAL MEM\n",
> + fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL MEM\n",
> "USED", used_pages, pages_to_size(used_pages, buf), pct);
>
> /*
> @@ -7745,7 +7750,7 @@ dump_kmeminfo(void)
> * pages that have a count of greater than 1.
> */
> pct = (shared_pages * 100)/totalram_pages;
> - fprintf(fp, "%10s %7ld %11s %3ld%% of TOTAL MEM\n",
> + fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL MEM\n",
> "SHARED", shared_pages, pages_to_size(shared_pages, buf), pct);
>
> subtract_buffer_pages = 0;
> @@ -7762,7 +7767,7 @@ dump_kmeminfo(void)
> buffer_pages = 0;
>
> pct = (buffer_pages * 100)/totalram_pages;
> - fprintf(fp, "%10s %7ld %11s %3ld%% of TOTAL MEM\n",
> + fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL MEM\n",
> "BUFFERS", buffer_pages, pages_to_size(buffer_pages, buf), pct);
>
> if (CRASHDEBUG(1))
> @@ -7816,7 +7821,7 @@ dump_kmeminfo(void)
>
>
> pct = (page_cache_size * 100)/totalram_pages;
> - fprintf(fp, "%10s %7ld %11s %3ld%% of TOTAL MEM\n",
> + fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL MEM\n",
> "CACHED", page_cache_size,
> pages_to_size(page_cache_size, buf), pct);
>
> @@ -7826,7 +7831,7 @@ dump_kmeminfo(void)
> */
>
> pct = (get_slabs * 100)/totalram_pages;
> - fprintf(fp, "%10s %7ld %11s %3ld%% of TOTAL MEM\n",
> + fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL MEM\n",
> "SLAB", get_slabs, pages_to_size(get_slabs, buf), pct);
>
> if (symbol_exists("totalhigh_pages")) {
> @@ -7851,7 +7856,7 @@ dump_kmeminfo(void)
>
> pct = totalhigh_pages ?
> (totalhigh_pages * 100)/totalram_pages : 0;
> - fprintf(fp, "\n%10s %7ld %11s %3ld%% of TOTAL MEM\n",
> + fprintf(fp, "\n%13s %7ld %11s %3ld%% of TOTAL MEM\n",
> "TOTAL HIGH", totalhigh_pages,
> pages_to_size(totalhigh_pages, buf), pct);
>
> @@ -7860,19 +7865,19 @@ dump_kmeminfo(void)
> freehighmem_pages = meminfo.retval;
> pct = freehighmem_pages ?
> (freehighmem_pages * 100)/totalhigh_pages : 0;
> - fprintf(fp, "%10s %7ld %11s %3ld%% of TOTAL HIGH\n",
> + fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL HIGH\n",
> "FREE HIGH", freehighmem_pages,
> pages_to_size(freehighmem_pages, buf), pct);
>
> totallowmem_pages = totalram_pages - totalhigh_pages;
> pct = (totallowmem_pages * 100)/totalram_pages;
> - fprintf(fp, "%10s %7ld %11s %3ld%% of TOTAL MEM\n",
> + fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL MEM\n",
> "TOTAL LOW", totallowmem_pages,
> pages_to_size(totallowmem_pages, buf), pct);
>
> freelowmem_pages = freeram_pages - freehighmem_pages;
> pct = (freelowmem_pages * 100)/totallowmem_pages;
> - fprintf(fp, "%10s %7ld %11s %3ld%% of TOTAL LOW\n",
> + fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL LOW\n",
> "FREE LOW", freelowmem_pages,
> pages_to_size(freelowmem_pages, buf), pct);
> }
> @@ -7884,18 +7889,18 @@ dump_kmeminfo(void)
> if (symbol_exists("swapper_space") || symbol_exists("swapper_spaces")) {
> if (dump_swap_info(RETURN_ON_ERROR, &totalswap_pages,
> &totalused_pages)) {
> - fprintf(fp, "%10s %7ld %11s ----\n",
> + fprintf(fp, "%13s %7ld %11s ----\n",
> "TOTAL SWAP", totalswap_pages,
> pages_to_size(totalswap_pages, buf));
> pct = totalswap_pages ? (totalused_pages * 100) /
> totalswap_pages : 100;
> - fprintf(fp, "%10s %7ld %11s %3ld%% of TOTAL SWAP\n",
> + fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL SWAP\n",
> "SWAP USED", totalused_pages,
> pages_to_size(totalused_pages, buf), pct);
> pct = totalswap_pages ?
> ((totalswap_pages - totalused_pages) *
> 100) / totalswap_pages : 0;
> - fprintf(fp, "%10s %7ld %11s %3ld%% of TOTAL SWAP\n",
> + fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL SWAP\n",
> "SWAP FREE",
> totalswap_pages - totalused_pages,
> pages_to_size(totalswap_pages - totalused_pages,
> @@ -7905,6 +7910,56 @@ dump_kmeminfo(void)
> "swap_info[%ld].swap_map at %lx is inaccessible\n",
> totalused_pages, totalswap_pages);
> }
> + /*
> + * Show committed memory
> + */
> + if (kernel_symbol_exists("sysctl_overcommit_memory")) {
> + fprintf(fp, "\n");
> + if (kernel_symbol_exists("sysctl_overcommit_kbytes")) {
> + get_symbol_data("sysctl_overcommit_kbytes",
> + sizeof(ulong), &overcommit_kbytes);
> + if (overcommit_kbytes)
> + allowed = overcommit_kbytes >>
> + (machdep->pageshift - 10);
> + else {
> + get_symbol_data("sysctl_overcommit_ratio",
> + sizeof(int),
> + &overcommit_ratio);
> + allowed = ((totalram_pages - hugetlb_total_pages())
> + * overcommit_ratio / 100);
> + }
> + }
> + if (symbol_exists("vm_committed_as")) {
> + readmem(symbol_value("vm_committed_as") +
> + MEMBER_OFFSET("percpu_counter",
> + "count"), KVADDR,
> + &committed,
> + sizeof(long),
> + "percpu_counter count",
> + FAULT_ON_ERROR);
> +
> + /* Ensure always positive */
> + if (committed < 0)
> + committed = 0;
> + } else {
> + readmem(symbol_value("vm_committed_space") +
> + MEMBER_OFFSET("atomic_t",
> + "counter"), KVADDR,
> + &committed, sizeof(int),
> + "atomic_t counter",
> + FAULT_ON_ERROR);
> + }
> + allowed += totalswap_pages;
> + fprintf(fp, "%13s %7ld %11s ----\n",
> + "COMMIT LIMIT", allowed,
> + pages_to_size(allowed, buf));
> +
> + pct = committed ? ((committed * 100)
> + / allowed) : 0;
> + fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL LIMIT\n",
> + "COMMITTED", committed,
> + pages_to_size(committed, buf), pct);
> + }
> dump_zone_page_usage();
> }
>
> @@ -14734,6 +14789,51 @@ next_physpage(ulonglong paddr, ulonglong *nextpaddr)
> return FALSE;
> }
>
> +ulong
> +hugetlb_total_pages(void)
> +{
> + ulong hstate_p;
> + int i, len;
> + ulong nr_total_pages = 0;
> + ulong nr_huge_pages;
> + uint horder;
> +
> + if (kernel_symbol_exists("hstates")) {
> + STRUCT_SIZE_INIT(hstate, "hstate");
> + MEMBER_OFFSET_INIT(hstate_order, "hstate", "order");
> + MEMBER_OFFSET_INIT(hstate_nr_huge_pages, "hstate", "nr_huge_pages");
> +
> + len = get_array_length("hstates", NULL, 0);
> + hstate_p = symbol_value("hstates");
> +
> + for (i = 0; i < len; i++) {
> + hstate_p = hstate_p + (SIZE(hstate) * i);
> +
> + readmem(hstate_p + OFFSET(hstate_order), KVADDR,
> + &horder, sizeof(uint),
> + "hstate_order",
> + FAULT_ON_ERROR);
> +
> + readmem(hstate_p + OFFSET(hstate_nr_huge_pages), KVADDR,
> + &nr_huge_pages, sizeof(ulong),
> + "hstate_nr_huge_pages",
> + FAULT_ON_ERROR);
> +
> + nr_total_pages += nr_huge_pages * (1 << horder);
> + }
> + } else if (kernel_symbol_exists("nr_huge_pages")) {
> + unsigned long hpage_shift = 21;
> +
> + if ((machine_type("X86") && !(machdep->flags & PAE)))
> + hpage_shift = 22;
> + get_symbol_data("nr_huge_pages",
> + sizeof(ulong), &nr_huge_pages);
> + nr_total_pages = nr_huge_pages * ((1 << hpage_shift) /
> + machdep->pagesize);
> + }
> + return nr_total_pages;
> +}
> +
> /*
> * Display swap statistics.
> */
> --
> 1.9.3
>
> --
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