Revision 64165b1affc5bc16231ac971e66aae7d68d57f2c authored by Hugh Dickins on 19 April 2019, 00:50:09 UTC, committed by Linus Torvalds on 19 April 2019, 16:46:04 UTC
The old try_to_unuse() implementation was driven by find_next_to_unuse(),
which terminated as soon as all the swap had been freed.

Add inuse_pages checks now (alongside signal_pending()) to stop scanning
mms and swap_map once finished.

The same ought to be done in shmem_unuse() too, but never was before,
and needs a different interface: so leave it as is for now.

Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1904081258200.1523@eggly.anvils
Fixes: b56a2d8af914 ("mm: rid swapoff of quadratic complexity")
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Kelley Nielsen <kelleynnn@gmail.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vineeth Pillai <vpillai@digitalocean.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Raw File
clz_ctz.c
/*
 * lib/clz_ctz.c
 *
 * Copyright (C) 2013 Chanho Min <chanho.min@lge.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 * The functions in this file aren't called directly, but are required by
 * GCC builtins such as __builtin_ctz, and therefore they can't be removed
 * despite appearing unreferenced in kernel source.
 *
 * __c[lt]z[sd]i2 can be overridden by linking arch-specific versions.
 */

#include <linux/export.h>
#include <linux/kernel.h>

int __weak __ctzsi2(int val);
int __weak __ctzsi2(int val)
{
	return __ffs(val);
}
EXPORT_SYMBOL(__ctzsi2);

int __weak __clzsi2(int val);
int __weak __clzsi2(int val)
{
	return 32 - fls(val);
}
EXPORT_SYMBOL(__clzsi2);

int __weak __clzdi2(long val);
int __weak __ctzdi2(long val);
#if BITS_PER_LONG == 32

int __weak __clzdi2(long val)
{
	return 32 - fls((int)val);
}
EXPORT_SYMBOL(__clzdi2);

int __weak __ctzdi2(long val)
{
	return __ffs((u32)val);
}
EXPORT_SYMBOL(__ctzdi2);

#elif BITS_PER_LONG == 64

int __weak __clzdi2(long val)
{
	return 64 - fls64((u64)val);
}
EXPORT_SYMBOL(__clzdi2);

int __weak __ctzdi2(long val)
{
	return __ffs64((u64)val);
}
EXPORT_SYMBOL(__ctzdi2);

#else
#error BITS_PER_LONG not 32 or 64
#endif
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