Re: [PATCH 8/8] scripts/gdb: Add meminfo command

From: Kieran Bingham
Date: Wed Feb 24 2016 - 04:44:26 EST


I had missed some PEP8 line length warnings on this patch - I've now
fixed them up. And a spurious 'pass' statement appeared (highlighted
inline), which I've removed.
--
Kieran

On 22/02/16 15:24, Kieran Bingham wrote:
> Provide an equivalent of /proc/meminfo which should be available from
> core dumps, or crashed kernels. This should allow a debugger to identify
> if memory pressures were applicable in the instance of their issue
>
> Signed-off-by: Kieran Bingham <kieran.bingham@xxxxxxxxxx>
>
> ---
>
> Changes from v1:
> - Updated to use LX_ macros for constants
> - Utilise the LX_CONFIG() options for conditional printing
> - Fixed meminfo command on Jan's target .config
> - Added missing segments to meminfo command (HUGEPAGE, QUICKLIST)
> - Adjusted for new list_for_each_entry() function
> - Fixed up for !CONFIG_SWAP and !CONFIG_MMU targets (Tested STM32)
> ---
> scripts/gdb/linux/constants.py.in | 34 ++++++
> scripts/gdb/linux/proc.py | 219 ++++++++++++++++++++++++++++++++++++++
> 2 files changed, 253 insertions(+)
>
> diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in
> index 57213ad8cf75..66562a8242bd 100644
> --- a/scripts/gdb/linux/constants.py.in
> +++ b/scripts/gdb/linux/constants.py.in
> @@ -12,8 +12,16 @@
> *
> */
>
> +#include <asm/page.h>
> +#include <asm/pgtable.h>
> +#include <asm/thread_info.h>
> +
> #include <linux/fs.h>
> +#include <linux/swap.h>
> #include <linux/mount.h>
> +#include <linux/huge_mm.h>
> +#include <linux/vmalloc.h>
> +
>
> /* We need to stringify expanded macros so that they can be parsed */
>
> @@ -51,3 +59,29 @@ LX_VALUE(MNT_NOATIME)
> LX_VALUE(MNT_NODIRATIME)
> LX_VALUE(MNT_RELATIME)
>
> +/* asm/page.h */
> +LX_GDBPARSED(PAGE_SHIFT)
> +
> +/* asm/thread_info.h */
> +LX_GDBPARSED(THREAD_SIZE)
> +
> +/* linux/vmalloc.h */
> +LX_GDBPARSED(VMALLOC_TOTAL)
> +
> +/* linux/swap.h */
> +LX_GDBPARSED(MAX_SWAPFILES)
> +
> +
> +/* Kernel Configs */
> +LX_CONFIG(CONFIG_HIGHMEM)
> +LX_CONFIG(CONFIG_MEMORY_FAILURE)
> +LX_CONFIG(CONFIG_TRANSPARENT_HUGEPAGE)
> +LX_CONFIG(CONFIG_CMA)
> +LX_CONFIG(CONFIG_MMU)
> +LX_CONFIG(CONFIG_SWAP)
> +
> +#ifndef CONFIG_NR_QUICK
> +#define CONFIG_NR_QUICK 0
> +#endif
> +LX_VALUE(CONFIG_NR_QUICK)
> +LX_CONFIG(CONFIG_QUICKLIST)
> diff --git a/scripts/gdb/linux/proc.py b/scripts/gdb/linux/proc.py
> index 44804e10493e..95933f66ea3e 100644
> --- a/scripts/gdb/linux/proc.py
> +++ b/scripts/gdb/linux/proc.py
> @@ -204,3 +204,222 @@ values of that process namespace"""
> info_opts(MNT_INFO, m_flags)))
>
> LxMounts()
> +
> +
> +bdev_type = utils.CachedType("struct block_device")
> +bdev_ptr_type = bdev_type.get_type().pointer()
> +
> +
> +class LxMeminfo(gdb.Command):
> + """ Identify the memory usage, statistics, and availability
> +
> +Equivalent to cat /proc/meminfo on a running target """
> +
> + def __init__(self):
> + super(LxMeminfo, self).__init__("lx-meminfo", gdb.COMMAND_DATA)
> +
> + def K(self, val):
> + # Convert from PAGES to KB
> + return int(val << (constants.LX_PAGE_SHIFT - 10))
> +
> + def page_K(self, remote_value):
> + # Obtain page value, and Convert from PAGES to KB
> + val = int(gdb.parse_and_eval(remote_value))
> + return self.K(val)
> +
> + def gps(self, enum_zone_stat_item):
> + # Access the Global Page State structure
> + # I would prefer to read this structure in one go and then index
> + # from the enum. But we can't determine the enum values with out
> + # a call to GDB anyway so we may as well take the easy route and
> + # get the value.
> + remote_value = "vm_stat[" + enum_zone_stat_item + "].counter"
> + return int(gdb.parse_and_eval(remote_value))
> +
> + def gps_K(self, enum_zone_stat_item):
> + return self.K(self.gps(enum_zone_stat_item))
> +
> + def nr_blockdev_pages(self):
> + bdevs_head = gdb.parse_and_eval("all_bdevs")
> + pages = 0
> + for bdev in lists.list_for_each_entry(bdevs_head, bdev_ptr_type, "bd_list"):
> + try:
> + pages += bdev['bd_inode']['i_mapping']['nrpages']
> + except:
> + # Any memory read failures are simply not counted
> + pass
> + return pages
> +
> + def total_swapcache_pages(self):
> + pages = 0
> + if not constants.LX_CONFIG_SWAP:
> + return 0
> +
> + for i in range(0, int(constants.LX_MAX_SWAPFILES)):
> + swap_space = "swapper_spaces[" + str(i) + "].nrpages"
> + pages += int(gdb.parse_and_eval(swap_space))
> + return pages
> +
> + def vm_commit_limit(self, totalram_pages):
> + total_swap_pages = 0
> + overcommit = int(gdb.parse_and_eval("sysctl_overcommit_kbytes"))
> + overcommit_ratio = int(gdb.parse_and_eval("sysctl_overcommit_ratio"))
> +
> + if constants.LX_CONFIG_SWAP:
> + total_swap_pages = int(gdb.parse_and_eval("total_swap_pages"))
> +
> + hugetlb_total_pages = 0 # hugetlb_total_pages()
> +
> + if overcommit:
> + allowed = overcommit >> (constants.LX_PAGE_SHIFT - 10)
> + else:
> + allowed = ((totalram_pages - hugetlb_total_pages *
> + overcommit_ratio / 100))
> +
> + allowed += total_swap_pages
> + return allowed
> +
> + def quicklist_total_size(self):
> + count = 0
> + quicklist = utils.gdb_eval_or_none("quicklist")
> + if quicklist is None:
> + return 0
> +
> + for cpu in cpus.each_online_cpu():
> + ql = cpus.per_cpu(quicklist, cpu)
> + for q in range(0, constants.LX_CONFIG_NR_QUICK):
> + # for (q = ql; q < ql + CONFIG_NR_QUICK; q++)
> + # count += q->nr_pages
> + count += ql[q]['nr_pages']
> +
> + return count
> +
> + # Main lx-meminfo command execution
> + # See fs/proc/meminfo.c:meminfo_proc_show()
> + def invoke(self, arg, from_tty):
> + totalram = int(gdb.parse_and_eval("totalram_pages"))
> + freeram = self.gps("NR_FREE_PAGES")
> + reclaimable = self.gps("NR_SLAB_RECLAIMABLE")
> + unreclaimable = self.gps("NR_SLAB_UNRECLAIMABLE")
> + slab = reclaimable + unreclaimable
> + # for_each_zone(zone)
> + # wmark_low += zone->watermark[WMARK_LOW];
> + wmark_low = 0 # Zone parsing is unimplemented
> +
> + available = freeram - wmark_low
> + available += reclaimable - min(reclaimable / 2, wmark_low)
> +
> + bufferram = self.nr_blockdev_pages()
> + total_swapcache_pages = self.total_swapcache_pages()
> +
> + file_pages = self.gps("NR_FILE_PAGES")
> + cached = file_pages - total_swapcache_pages - bufferram
> +
> + # LRU Pages
> + active_pages_anon = self.gps("NR_ACTIVE_ANON")
> + inactive_pages_anon = self.gps("NR_INACTIVE_ANON")
> + active_pages_file = self.gps("NR_ACTIVE_FILE")
> + inactive_pages_file = self.gps("NR_INACTIVE_FILE")
> + unevictable_pages = self.gps("NR_UNEVICTABLE")
> + active_pages = active_pages_anon + active_pages_file
> + inactive_pages = inactive_pages_anon + inactive_pages_file
> +
> + kernelstack = int(self.gps("NR_KERNEL_STACK") *
> + constants.LX_THREAD_SIZE / 1024)
> +
> + commitlimit = int(self.vm_commit_limit(totalram))
> + committed_as = int(gdb.parse_and_eval("vm_committed_as.count"))
> +
> + vmalloc_total = int(constants.LX_VMALLOC_TOTAL >> 10)
> +
> + gdb.write(
> + "MemTotal: {:8d} kB\n".format(self.K(totalram)) +
> + "MemFree: {:8d} kB\n".format(self.K(freeram)) +
> + "MemAvailable: {:8d} kB\n".format(self.K(available)) +
> + "Buffers: {:8d} kB\n".format(self.K(bufferram)) +
> + "Cached: {:8d} kB\n".format(self.K(cached)) +
> + "SwapCached: {:8d} kB\n".format(self.K(total_swapcache_pages)) +
> + "Active: {:8d} kB\n".format(self.K(active_pages)) +
> + "Inactive: {:8d} kB\n".format(self.K(inactive_pages)) +
> + "Active(anon): {:8d} kB\n".format(self.K(active_pages_anon)) +
> + "Inactive(anon): {:8d} kB\n".format(self.K(inactive_pages_anon)) +
> + "Active(file): {:8d} kB\n".format(self.K(active_pages_file)) +
> + "Inactive(file): {:8d} kB\n".format(self.K(inactive_pages_file)) +
> + "Unevictable: {:8d} kB\n".format(self.K(unevictable_pages)) +
> + "Mlocked: {:8d} kB\n".format(self.gps_K("NR_MLOCK"))
> + )
> + if constants.LX_CONFIG_HIGHMEM:
> + totalhigh = int(gdb.parse_and_eval("totalhigh_pages"))
> + freehigh = int(gdb.parse_and_eval("nr_free_highpages()"))
> + gdb.write(
> + "HighTotal: {:8d} kB\n".format(self.K(totalhigh)) +
> + "HighFree: {:8d} kB\n".format(self.K(freehigh)) +
> + "LowTotal: {:8d} kB\n".format(self.K(totalram-totalhigh)) +
> + "LowFree: {:8d} kB\n".format(self.K(freeram-freehigh))
> + )
> + if not constants.LX_CONFIG_MMU:
> + mmap_pages_allocated = gdb.parse_and_eval("mmap_pages_allocated.counter")
> + gdb.write(
> + "MmapCopy: {:8d} kB\n".format(self.K(mmap_pages_allocated))
> +
> + )

> + pass

Hrm ... No idea where this 'pass' statement crept in ... It has been
dropped for the next patch version.

> +
> + gdb.write(
> + "SwapTotal: {:8d} kB\n".format(self.K(0)) +
> + "SwapFree: {:8d} kB\n".format(self.K(0)) +
> + "Dirty: {:8d} kB\n".format(self.gps_K("NR_FILE_DIRTY")) +
> + "Writeback: {:8d} kB\n".format(self.gps_K("NR_WRITEBACK")) +
> + "AnonPages: {:8d} kB\n".format(self.gps_K("NR_ANON_PAGES")) +
> + "Mapped: {:8d} kB\n".format(self.gps_K("NR_FILE_MAPPED")) +
> + "Shmem: {:8d} kB\n".format(self.gps_K("NR_SHMEM")) +
> + "Slab: {:8d} kB\n".format(self.K(slab)) +
> + "SReclaimable: {:8d} kB\n".format(self.K(reclaimable)) +
> + "SUnreclaim: {:8d} kB\n".format(self.K(unreclaimable)) +
> + "KernelStack: {:8d} kB\n".format(kernelstack) +
> + "PageTables: {:8d} kB\n".format(self.gps_K("NR_PAGETABLE"))
> + )
> +
> + if constants.LX_CONFIG_QUICKLIST:
> + quicklist = self.quicklist_total_size()
> + gdb.write(
> + "Quicklists: {:8d} kB\n".format(self.K(quicklist))
> + )
> +
> + gdb.write(
> + "NFS_Unstable: {:8d} kB\n".format(self.gps_K("NR_UNSTABLE_NFS")) +
> + "Bounce: {:8d} kB\n".format(self.gps_K("NR_BOUNCE")) +
> + "WritebackTmp: {:8d} kB\n".format(self.gps_K("NR_WRITEBACK_TEMP"))
> + )
> +
> + gdb.write(
> + "CommitLimit: {:8d} kB\n".format(self.K(commitlimit)) +
> + "Committed_AS: {:8d} kB\n".format(self.K(committed_as)) +
> + "VmallocTotal: {:8d} kB\n".format(vmalloc_total)
> + )
> +
> + # These are always zero now
> + gdb.write(
> + "VmallocUsed: {:8d} kB\n".format(0) +
> + "VmallocChunk: {:8d} kB\n".format(0)
> + )
> +
> + if constants.LX_CONFIG_MEMORY_FAILURE:
> + gdb.write(
> + "HardwareCorrupted: {:8d} kB\n"
> + )
> + if constants.LX_CONFIG_TRANSPARENT_HUGEPAGE:
> + huge = self.gps("NR_ANON_TRANSPARENT_HUGEPAGES")
> + # HPAGE_PMD_NR can not be determined in constants.py
> + gdb.write(
> + "AnonHugePages: {:8d} kB ( * HPAGE_PMD_NR )\n"
> + .format(self.K(huge))
> + )
> + if constants.LX_CONFIG_CMA:
> + totalcma_pages = int(gdb.parse_and_eval("totalcma_pages"))
> + gdb.write(
> + "CmaTotal: {:8d} kB\n".format(self.K(totalcma_pages)) +
> + "CmaFree: {:8d} kB\n".format(self.gps_K("NR_FREE_CMA_PAGES"))
> + )
> +
> +LxMeminfo()
>