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Message-ID: <202211020508.MbGW51iV-lkp@intel.com>
Date: Wed, 2 Nov 2022 05:23:22 +0800
From: kernel test robot <lkp@...el.com>
To: TGSP <tgsp002@...il.com>, rafael@...nel.org, len.brown@...el.com,
pavel@....cz, huanglei@...inos.cn
Cc: llvm@...ts.linux.dev, oe-kbuild-all@...ts.linux.dev,
linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
xiongxin <xiongxin@...inos.cn>, stable@...r.kernel.org
Subject: Re: [PATCH -next 2/2] PM: hibernate: add check of preallocate mem
for image size pages
Hi TGSP,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on next-20221031]
url: https://github.com/intel-lab-lkp/linux/commits/TGSP/Fixes-to-the-hibernate_preallocate_memory/20221101-105416
patch link: https://lore.kernel.org/r/20221101022840.1351163-3-tgsp002%40gmail.com
patch subject: [PATCH -next 2/2] PM: hibernate: add check of preallocate mem for image size pages
config: i386-randconfig-a011
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/1c277961f43154d671520086d9626e081e072b90
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review TGSP/Fixes-to-the-hibernate_preallocate_memory/20221101-105416
git checkout 1c277961f43154d671520086d9626e081e072b90
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash kernel/power/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@...el.com>
All warnings (new ones prefixed by >>):
>> kernel/power/snapshot.c:1867:3: warning: variable 'size_highmem' is uninitialized when used here [-Wuninitialized]
size_highmem += preallocate_image_highmem(alloc - size);
^~~~~~~~~~~~
kernel/power/snapshot.c:1741:28: note: initialize the variable 'size_highmem' to silence this warning
unsigned long size_highmem;
^
= 0
1 warning generated.
vim +/size_highmem +1867 kernel/power/snapshot.c
1713
1714 /**
1715 * hibernate_preallocate_memory - Preallocate memory for hibernation image.
1716 *
1717 * To create a hibernation image it is necessary to make a copy of every page
1718 * frame in use. We also need a number of page frames to be free during
1719 * hibernation for allocations made while saving the image and for device
1720 * drivers, in case they need to allocate memory from their hibernation
1721 * callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough
1722 * estimate) and reserved_size divided by PAGE_SIZE (which is tunable through
1723 * /sys/power/reserved_size, respectively). To make this happen, we compute the
1724 * total number of available page frames and allocate at least
1725 *
1726 * ([page frames total] - PAGES_FOR_IO - [metadata pages]) / 2
1727 * - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE)
1728 *
1729 * of them, which corresponds to the maximum size of a hibernation image.
1730 *
1731 * If image_size is set below the number following from the above formula,
1732 * the preallocation of memory is continued until the total number of saveable
1733 * pages in the system is below the requested image size or the minimum
1734 * acceptable image size returned by minimum_image_size(), whichever is greater.
1735 */
1736 int hibernate_preallocate_memory(void)
1737 {
1738 struct zone *zone;
1739 unsigned long saveable, size, max_size, count, highmem, pages = 0;
1740 unsigned long alloc, save_highmem, pages_highmem, avail_normal;
1741 unsigned long size_highmem;
1742 ktime_t start, stop;
1743 int error;
1744
1745 pr_info("Preallocating image memory\n");
1746 start = ktime_get();
1747
1748 error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
1749 if (error) {
1750 pr_err("Cannot allocate original bitmap\n");
1751 goto err_out;
1752 }
1753
1754 error = memory_bm_create(©_bm, GFP_IMAGE, PG_ANY);
1755 if (error) {
1756 pr_err("Cannot allocate copy bitmap\n");
1757 goto err_out;
1758 }
1759
1760 alloc_normal = 0;
1761 alloc_highmem = 0;
1762
1763 /* Count the number of saveable data pages. */
1764 save_highmem = count_highmem_pages();
1765 saveable = count_data_pages();
1766
1767 /*
1768 * Compute the total number of page frames we can use (count) and the
1769 * number of pages needed for image metadata (size).
1770 */
1771 count = saveable;
1772 saveable += save_highmem;
1773 highmem = save_highmem;
1774 size = 0;
1775 for_each_populated_zone(zone) {
1776 size += snapshot_additional_pages(zone);
1777 if (is_highmem(zone))
1778 highmem += zone_page_state(zone, NR_FREE_PAGES);
1779 else
1780 count += zone_page_state(zone, NR_FREE_PAGES);
1781 }
1782 avail_normal = count;
1783 count += highmem;
1784 count -= totalreserve_pages;
1785
1786 /* Compute the maximum number of saveable pages to leave in memory. */
1787 max_size = (count - (size + PAGES_FOR_IO)) / 2
1788 - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE);
1789 /* Compute the desired number of image pages specified by image_size. */
1790 size = DIV_ROUND_UP(image_size, PAGE_SIZE);
1791 if (size > max_size)
1792 size = max_size;
1793 /*
1794 * If the desired number of image pages is at least as large as the
1795 * current number of saveable pages in memory, allocate page frames for
1796 * the image and we're done.
1797 */
1798 if (size >= saveable) {
1799 pages = preallocate_image_highmem(save_highmem);
1800 pages += preallocate_image_memory(saveable - pages, avail_normal);
1801 goto out;
1802 }
1803
1804 /* Estimate the minimum size of the image. */
1805 pages = minimum_image_size(saveable);
1806 /*
1807 * To avoid excessive pressure on the normal zone, leave room in it to
1808 * accommodate an image of the minimum size (unless it's already too
1809 * small, in which case don't preallocate pages from it at all).
1810 */
1811 if (avail_normal > pages)
1812 avail_normal -= pages;
1813 else
1814 avail_normal = 0;
1815 if (size < pages)
1816 size = min_t(unsigned long, pages, max_size);
1817
1818 /*
1819 * Let the memory management subsystem know that we're going to need a
1820 * large number of page frames to allocate and make it free some memory.
1821 * NOTE: If this is not done, performance will be hurt badly in some
1822 * test cases.
1823 */
1824 shrink_all_memory(saveable - size);
1825
1826 /*
1827 * The number of saveable pages in memory was too high, so apply some
1828 * pressure to decrease it. First, make room for the largest possible
1829 * image and fail if that doesn't work. Next, try to decrease the size
1830 * of the image as much as indicated by 'size' using allocations from
1831 * highmem and non-highmem zones separately.
1832 */
1833 pages_highmem = preallocate_image_highmem(highmem / 2);
1834 alloc = count - max_size;
1835 if (alloc > pages_highmem)
1836 alloc -= pages_highmem;
1837 else
1838 alloc = 0;
1839 pages = preallocate_image_memory(alloc, avail_normal);
1840 if (pages < alloc) {
1841 /* We have exhausted non-highmem pages, try highmem. */
1842 alloc -= pages;
1843 pages += pages_highmem;
1844 pages_highmem = preallocate_image_highmem(alloc);
1845 if (pages_highmem < alloc) {
1846 pr_err("Image allocation is %lu pages short\n",
1847 alloc - pages_highmem);
1848 goto err_out;
1849 }
1850 pages += pages_highmem;
1851 /*
1852 * size is the desired number of saveable pages to leave in
1853 * memory, so try to preallocate (all memory - size) pages.
1854 */
1855 alloc = (count - pages) - size;
1856 pages += preallocate_image_highmem(alloc);
1857 } else {
1858 /*
1859 * There are approximately max_size saveable pages at this point
1860 * and we want to reduce this number down to size.
1861 */
1862 alloc = max_size - size;
1863 size = preallocate_highmem_fraction(alloc, highmem, count);
1864 pages_highmem += size;
1865 alloc -= size;
1866 size = preallocate_image_memory(alloc, avail_normal);
> 1867 size_highmem += preallocate_image_highmem(alloc - size);
1868 if (size_highmem < (alloc - size)) {
1869 pr_err("Image allocation is %lu pages short, exit\n",
1870 alloc - size - pages_highmem);
1871 goto err_out;
1872 }
1873 pages_highmem += size_highmem;
1874 pages += pages_highmem + size;
1875 }
1876
1877 /*
1878 * We only need as many page frames for the image as there are saveable
1879 * pages in memory, but we have allocated more. Release the excessive
1880 * ones now.
1881 */
1882 pages -= free_unnecessary_pages();
1883
1884 out:
1885 stop = ktime_get();
1886 pr_info("Allocated %lu pages for snapshot\n", pages);
1887 swsusp_show_speed(start, stop, pages, "Allocated");
1888
1889 return 0;
1890
1891 err_out:
1892 swsusp_free();
1893 return -ENOMEM;
1894 }
1895
--
0-DAY CI Kernel Test Service
https://01.org/lkp
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