Commit 4248b0da authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

fs, file table: reinit files_stat.max_files after deferred memory initialisation 



Dave Hansen reported the following;

	My laptop has been behaving strangely with 4.2-rc2.  Once I log
	in to my X session, I start getting all kinds of strange errors
	from applications and see this in my dmesg:

        	VFS: file-max limit 8192 reached

The problem is that the file-max is calculated before memory is fully
initialised and miscalculates how much memory the kernel is using.  This
patch recalculates file-max after deferred memory initialisation.  Note
that using memory hotplug infrastructure would not have avoided this
problem as the value is not recalculated after memory hot-add.

4.1:             files_stat.max_files = 6582781
4.2-rc2:         files_stat.max_files = 8192
4.2-rc2 patched: files_stat.max_files = 6562467

Small differences with the patch applied and 4.1 but not enough to matter.

Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
Reported-by: default avatarDave Hansen <dave.hansen@intel.com>
Cc: Nicolai Stange <nicstange@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Alex Ng <alexng@microsoft.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d3cd131d

fs/dcache.c

+3 −10
Original line number Diff line number Diff line
@@ -3442,22 +3442,15 @@ void __init vfs_caches_init_early(void) 
	inode_init_early();

}



void __init vfs_caches_init(unsigned long mempages)

void __init vfs_caches_init(void)

{

	unsigned long reserve;



	/* Base hash sizes on available memory, with a reserve equal to

           150% of current kernel size */



	reserve = min((mempages - nr_free_pages()) * 3/2, mempages - 1);

	mempages -= reserve;



	names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0,

			SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);



	dcache_init();

	inode_init();

	files_init(mempages);

	files_init();

	files_maxfiles_init();

	mnt_init();

	bdev_cache_init();

	chrdev_init();

fs/file_table.c

+15 −9
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/hardirq.h>

#include <linux/task_work.h>

#include <linux/ima.h>

#include <linux/swap.h>



#include <linux/atomic.h>
@@ -308,19 +309,24 @@ void put_filp(struct file *file) 
	}

}



void __init files_init(unsigned long mempages)

void __init files_init(void)

{ 

	unsigned long n;



	filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0,

			SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);

	percpu_counter_init(&nr_files, 0, GFP_KERNEL);

}



/*

	 * One file with associated inode and dcache is very roughly 1K.

	 * Per default don't use more than 10% of our memory for files. 

 * One file with associated inode and dcache is very roughly 1K. Per default

 * do not use more than 10% of our memory for files.

 */

void __init files_maxfiles_init(void)

{

	unsigned long n;

	unsigned long memreserve = (totalram_pages - nr_free_pages()) * 3/2;



	memreserve = min(memreserve, totalram_pages - 1);

	n = ((totalram_pages - memreserve) * (PAGE_SIZE / 1024)) / 10;



	n = (mempages * (PAGE_SIZE / 1024)) / 10;

	files_stat.max_files = max_t(unsigned long, n, NR_FILE);

	percpu_counter_init(&nr_files, 0, GFP_KERNEL);

}

include/linux/fs.h

+3 −2
Original line number Diff line number Diff line
@@ -55,7 +55,8 @@ struct vm_fault; 


extern void __init inode_init(void);

extern void __init inode_init_early(void);

extern void __init files_init(unsigned long);

extern void __init files_init(void);

extern void __init files_maxfiles_init(void);



extern struct files_stat_struct files_stat;

extern unsigned long get_max_files(void);
@@ -2245,7 +2246,7 @@ extern int ioctl_preallocate(struct file *filp, void __user *argp); 


/* fs/dcache.c */

extern void __init vfs_caches_init_early(void);

extern void __init vfs_caches_init(unsigned long);

extern void __init vfs_caches_init(void);



extern struct kmem_cache *names_cachep;

init/main.c

+1 −1
Original line number Diff line number Diff line
@@ -656,7 +656,7 @@ asmlinkage __visible void __init start_kernel(void) 
	key_init();

	security_init();

	dbg_late_init();

	vfs_caches_init(totalram_pages);

	vfs_caches_init();

	signals_init();

	/* rootfs populating might need page-writeback */

	page_writeback_init();

mm/page_alloc.c

+3 −0
Original line number Diff line number Diff line
@@ -1201,6 +1201,9 @@ void __init page_alloc_init_late(void) 


	/* Block until all are initialised */

	wait_for_completion(&pgdat_init_all_done_comp);



	/* Reinit limits that are based on free pages after the kernel is up */

	files_maxfiles_init();

}

#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */

CRA Git | Maintained and supported by SUSTech CRA and CCSE