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

[Kieran Bingham]

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()
>