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    include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
    Tejun Heo 提交于
    include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
    
    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files.  percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.
    
    percpu.h -> slab.h dependency is about to be removed.  Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability.  As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.
    
      http://userweb.kernel.org/~tj/misc/slabh-sweep.py
    
    The script does the followings.
    
    * Scan files for gfp and slab usages and update includes such that
      only the necessary includes are there.  ie. if only gfp is used,
      gfp.h, if slab is used, slab.h.
    
    * When the script inserts a new include, it looks at the include
      blocks and try to put the new include such that its order conforms
      to its surrounding.  It's put in the include block which contains
      core kernel includes, in the same order that the rest are ordered -
      alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
      doesn't seem to be any matching order.
    
    * If the script can't find a place to put a new include (mostly
      because the file doesn't have fitting include block), it prints out
      an error message indicating which .h file needs to be added to the
      file.
    
    The conversion was done in the following steps.
    
    1. The initial automatic conversion of all .c files updated slightly
       over 4000 files, deleting around 700 includes and adding ~480 gfp.h
       and ~3000 slab.h inclusions.  The script emitted errors for ~400
       files.
    
    2. Each error was manually checked.  Some didn't need the inclusion,
       some needed manual addition while adding it to implementation .h or
       embedding .c file was more appropriate for others.  This step added
       inclusions to around 150 files.
    
    3. The script was run again and the output was compared to the edits
       from #2 to make sure no file was left behind.
    
    4. Several build tests were done and a couple of problems were fixed.
       e.g. lib/decompress_*.c used malloc/free() wrappers around slab
       APIs requiring slab.h to be added manually.
    
    5. The script was run on all .h files but without automatically
       editing them as sprinkling gfp.h and slab.h inclusions around .h
       files could easily lead to inclusion dependency hell.  Most gfp.h
       inclusion directives were ignored as stuff from gfp.h was usually
       wildly available and often used in preprocessor macros.  Each
       slab.h inclusion directive was examined and added manually as
       necessary.
    
    6. percpu.h was updated not to include slab.h.
    
    7. Build test were done on the following configurations and failures
       were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
       distributed build env didn't work with gcov compiles) and a few
       more options had to be turned off depending on archs to make things
       build (like ipr on powerpc/64 which failed due to missing writeq).
    
       * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
       * powerpc and powerpc64 SMP allmodconfig
       * sparc and sparc64 SMP allmodconfig
       * ia64 SMP allmodconfig
       * s390 SMP allmodconfig
       * alpha SMP allmodconfig
       * um on x86_64 SMP allmodconfig
    
    8. percpu.h modifications were reverted so that it could be applied as
       a separate patch and serve as bisection point.
    
    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.
    Signed-off-by: NTejun Heo <tj@kernel.org>
    Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
    5a0e3ad6
quicklist.c 2.4 KB
/*
 * Quicklist support.
 *
 * Quicklists are light weight lists of pages that have a defined state
 * on alloc and free. Pages must be in the quicklist specific defined state
 * (zero by default) when the page is freed. It seems that the initial idea
 * for such lists first came from Dave Miller and then various other people
 * improved on it.
 *
 * Copyright (C) 2007 SGI,
 * 	Christoph Lameter <clameter@sgi.com>
 * 		Generalized, added support for multiple lists and
 * 		constructors / destructors.
 */
#include <linux/kernel.h>

#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/module.h>
#include <linux/quicklist.h>

DEFINE_PER_CPU(struct quicklist [CONFIG_NR_QUICK], quicklist);

#define FRACTION_OF_NODE_MEM	16

static unsigned long max_pages(unsigned long min_pages)
{
	unsigned long node_free_pages, max;
	int node = numa_node_id();
	struct zone *zones = NODE_DATA(node)->node_zones;
	int num_cpus_on_node;

	node_free_pages =
#ifdef CONFIG_ZONE_DMA
		zone_page_state(&zones[ZONE_DMA], NR_FREE_PAGES) +
#endif
#ifdef CONFIG_ZONE_DMA32
		zone_page_state(&zones[ZONE_DMA32], NR_FREE_PAGES) +
#endif
		zone_page_state(&zones[ZONE_NORMAL], NR_FREE_PAGES);

	max = node_free_pages / FRACTION_OF_NODE_MEM;

	num_cpus_on_node = cpumask_weight(cpumask_of_node(node));
	max /= num_cpus_on_node;

	return max(max, min_pages);
}

static long min_pages_to_free(struct quicklist *q,
	unsigned long min_pages, long max_free)
{
	long pages_to_free;

	pages_to_free = q->nr_pages - max_pages(min_pages);

	return min(pages_to_free, max_free);
}

/*
 * Trim down the number of pages in the quicklist
 */
void quicklist_trim(int nr, void (*dtor)(void *),
	unsigned long min_pages, unsigned long max_free)
{
	long pages_to_free;
	struct quicklist *q;

	q = &get_cpu_var(quicklist)[nr];
	if (q->nr_pages > min_pages) {
		pages_to_free = min_pages_to_free(q, min_pages, max_free);

		while (pages_to_free > 0) {
			/*
			 * We pass a gfp_t of 0 to quicklist_alloc here
			 * because we will never call into the page allocator.
			 */
			void *p = quicklist_alloc(nr, 0, NULL);

			if (dtor)
				dtor(p);
			free_page((unsigned long)p);
			pages_to_free--;
		}
	}
	put_cpu_var(quicklist);
}

unsigned long quicklist_total_size(void)
{
	unsigned long count = 0;
	int cpu;
	struct quicklist *ql, *q;

	for_each_online_cpu(cpu) {
		ql = per_cpu(quicklist, cpu);
		for (q = ql; q < ql + CONFIG_NR_QUICK; q++)
			count += q->nr_pages;
	}
	return count;
}
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