shmem: prepare huge= mount option and sysfs knob (5a6e75f8) · Commits · 戴 / test

include/linux/huge_mm.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -41,6 +41,8 @@ enum transparent_hugepage_flag {
		#endif
		};

		extern struct kobj_attribute shmem_enabled_attr;

		#define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
		#define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)

include/linux/shmem_fs.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -28,9 +28,10 @@ struct shmem_sb_info {
		unsigned long max_inodes; /* How many inodes are allowed */
		unsigned long free_inodes; /* How many are left for allocation */
		spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
		umode_t mode; /* Mount mode for root directory */
		unsigned char huge; /* Whether to try for hugepages */
		kuid_t uid; /* Mount uid for root directory */
		kgid_t gid; /* Mount gid for root directory */
		umode_t mode; /* Mount mode for root directory */
		struct mempolicy mpol; / default memory policy for mappings */
		};

mm/huge_memory.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -442,6 +442,9 @@ static struct attribute *hugepage_attr[] = {
		&enabled_attr.attr,
		&defrag_attr.attr,
		&use_zero_page_attr.attr,
		#ifdef CONFIG_SHMEM
		&shmem_enabled_attr.attr,
		#endif
		#ifdef CONFIG_DEBUG_VM
		&debug_cow_attr.attr,
		#endif

mm/shmem.c

+161 −0

Original line number	Diff line number	Diff line
		@@ -288,6 +288,87 @@ static bool shmem_confirm_swap(struct address_space *mapping,
		return item == swp_to_radix_entry(swap);
		}

		/*
		* Definitions for "huge tmpfs": tmpfs mounted with the huge= option
		*
		* SHMEM_HUGE_NEVER:
		* disables huge pages for the mount;
		* SHMEM_HUGE_ALWAYS:
		* enables huge pages for the mount;
		* SHMEM_HUGE_WITHIN_SIZE:
		* only allocate huge pages if the page will be fully within i_size,
		* also respect fadvise()/madvise() hints;
		* SHMEM_HUGE_ADVISE:
		* only allocate huge pages if requested with fadvise()/madvise();
		*/

		#define SHMEM_HUGE_NEVER 0
		#define SHMEM_HUGE_ALWAYS 1
		#define SHMEM_HUGE_WITHIN_SIZE 2
		#define SHMEM_HUGE_ADVISE 3

		/*
		* Special values.
		* Only can be set via /sys/kernel/mm/transparent_hugepage/shmem_enabled:
		*
		* SHMEM_HUGE_DENY:
		* disables huge on shm_mnt and all mounts, for emergency use;
		* SHMEM_HUGE_FORCE:
		* enables huge on shm_mnt and all mounts, w/o needing option, for testing;
		*
		*/
		#define SHMEM_HUGE_DENY (-1)
		#define SHMEM_HUGE_FORCE (-2)

		#ifdef CONFIG_TRANSPARENT_HUGEPAGE
		/* ifdef here to avoid bloating shmem.o when not necessary */

		int shmem_huge __read_mostly;

		static int shmem_parse_huge(const char *str)
		{
		if (!strcmp(str, "never"))
		return SHMEM_HUGE_NEVER;
		if (!strcmp(str, "always"))
		return SHMEM_HUGE_ALWAYS;
		if (!strcmp(str, "within_size"))
		return SHMEM_HUGE_WITHIN_SIZE;
		if (!strcmp(str, "advise"))
		return SHMEM_HUGE_ADVISE;
		if (!strcmp(str, "deny"))
		return SHMEM_HUGE_DENY;
		if (!strcmp(str, "force"))
		return SHMEM_HUGE_FORCE;
		return -EINVAL;
		}

		static const char *shmem_format_huge(int huge)
		{
		switch (huge) {
		case SHMEM_HUGE_NEVER:
		return "never";
		case SHMEM_HUGE_ALWAYS:
		return "always";
		case SHMEM_HUGE_WITHIN_SIZE:
		return "within_size";
		case SHMEM_HUGE_ADVISE:
		return "advise";
		case SHMEM_HUGE_DENY:
		return "deny";
		case SHMEM_HUGE_FORCE:
		return "force";
		default:
		VM_BUG_ON(1);
		return "bad_val";
		}
		}

		#else /* !CONFIG_TRANSPARENT_HUGEPAGE */

		#define shmem_huge SHMEM_HUGE_DENY

		#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

		/*
		* Like add_to_page_cache_locked, but error if expected item has gone.
		*/
		@@ -2860,11 +2941,24 @@ static int shmem_parse_options(char options, struct shmem_sb_info sbinfo,
		sbinfo->gid = make_kgid(current_user_ns(), gid);
		if (!gid_valid(sbinfo->gid))
		goto bad_val;
		#ifdef CONFIG_TRANSPARENT_HUGEPAGE
		} else if (!strcmp(this_char, "huge")) {
		int huge;
		huge = shmem_parse_huge(value);
		if (huge < 0)
		goto bad_val;
		if (!has_transparent_hugepage() &&
		huge != SHMEM_HUGE_NEVER)
		goto bad_val;
		sbinfo->huge = huge;
		#endif
		#ifdef CONFIG_NUMA
		} else if (!strcmp(this_char,"mpol")) {
		mpol_put(mpol);
		mpol = NULL;
		if (mpol_parse_str(value, &mpol))
		goto bad_val;
		#endif
		} else {
		pr_err("tmpfs: Bad mount option %s\n", this_char);
		goto error;
		@@ -2910,6 +3004,7 @@ static int shmem_remount_fs(struct super_block sb, int flags, char *data)
		goto out;

		error = 0;
		sbinfo->huge = config.huge;
		sbinfo->max_blocks = config.max_blocks;
		sbinfo->max_inodes = config.max_inodes;
		sbinfo->free_inodes = config.max_inodes - inodes;
		@@ -2943,6 +3038,11 @@ static int shmem_show_options(struct seq_file seq, struct dentry root)
		if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
		seq_printf(seq, ",gid=%u",
		from_kgid_munged(&init_user_ns, sbinfo->gid));
		#ifdef CONFIG_TRANSPARENT_HUGEPAGE
		/* Rightly or wrongly, show huge mount option unmasked by shmem_huge */
		if (sbinfo->huge)
		seq_printf(seq, ",huge=%s", shmem_format_huge(sbinfo->huge));
		#endif
		shmem_show_mpol(seq, sbinfo->mpol);
		return 0;
		}
		@@ -3282,6 +3382,13 @@ int __init shmem_init(void)
		pr_err("Could not kern_mount tmpfs\n");
		goto out1;
		}

		#ifdef CONFIG_TRANSPARENT_HUGEPAGE
		if (has_transparent_hugepage() && shmem_huge < SHMEM_HUGE_DENY)
		SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
		else
		shmem_huge = 0; /* just in case it was patched */
		#endif
		return 0;

		out1:
		@@ -3293,6 +3400,60 @@ out3:
		return error;
		}

		#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && defined(CONFIG_SYSFS)
		static ssize_t shmem_enabled_show(struct kobject *kobj,
		struct kobj_attribute attr, char buf)
		{
		int values[] = {
		SHMEM_HUGE_ALWAYS,
		SHMEM_HUGE_WITHIN_SIZE,
		SHMEM_HUGE_ADVISE,
		SHMEM_HUGE_NEVER,
		SHMEM_HUGE_DENY,
		SHMEM_HUGE_FORCE,
		};
		int i, count;

		for (i = 0, count = 0; i < ARRAY_SIZE(values); i++) {
		const char *fmt = shmem_huge == values[i] ? "[%s] " : "%s ";

		count += sprintf(buf + count, fmt,
		shmem_format_huge(values[i]));
		}
		buf[count - 1] = '\n';
		return count;
		}

		static ssize_t shmem_enabled_store(struct kobject *kobj,
		struct kobj_attribute attr, const char buf, size_t count)
		{
		char tmp[16];
		int huge;

		if (count + 1 > sizeof(tmp))
		return -EINVAL;
		memcpy(tmp, buf, count);
		tmp[count] = '\0';
		if (count && tmp[count - 1] == '\n')
		tmp[count - 1] = '\0';

		huge = shmem_parse_huge(tmp);
		if (huge == -EINVAL)
		return -EINVAL;
		if (!has_transparent_hugepage() &&
		huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY)
		return -EINVAL;

		shmem_huge = huge;
		if (shmem_huge < SHMEM_HUGE_DENY)
		SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
		return count;
		}

		struct kobj_attribute shmem_enabled_attr =
		__ATTR(shmem_enabled, 0644, shmem_enabled_show, shmem_enabled_store);
		#endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_SYSFS */

		#else /* !CONFIG_SHMEM */

		/*

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