Make a few cleanups in mm/shmem.c, before going on to complicate it.
shmem_alloc_page() will become more complicated: we can't afford to
to have that complication duplicated between a CONFIG_NUMA version
and a !CONFIG_NUMA version, so rearrange the #ifdef'ery there to
yield a single shmem_swapin() and a single shmem_alloc_page().
Yes, it's a shame to inflict the horrid pseudo-vma on non-NUMA
configurations, but one day we'll get around to eliminating it
(elsewhere I have an alloc_pages_mpol() patch, but mpol handling is
subtle and bug-prone, and changed yet again since my last version).
Move __set_page_locked __SetPageSwapBacked from shmem_getpage_gfp()
to shmem_alloc_page(): that SwapBacked flag will be useful in future,
to help it to distinguish different cases appropriately.
And the SGP_DIRTY variant of SGP_CACHE is hard to understand and of
little use (IIRC it dates back to when shmem_getpage() returned the
page unlocked): let's kill it and just do the necessary in
do_shmem_file_read().
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
---
include/linux/mempolicy.h | 6 ++
mm/shmem.c | 73 +++++++++++++-----------------------
2 files changed, 34 insertions(+), 45 deletions(-)
--- thpfs.orig/include/linux/mempolicy.h 2014-12-07 14:21:05.000000000 -0800
+++ thpfs/include/linux/mempolicy.h 2015-02-20 19:33:46.112050733 -0800
@@ -228,6 +228,12 @@ static inline void mpol_free_shared_poli
{
}
+static inline struct mempolicy *
+mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
+{
+ return NULL;
+}
+
#define vma_policy(vma) NULL
static inline int
--- thpfs.orig/mm/shmem.c 2015-02-20 19:33:35.676074594 -0800
+++ thpfs/mm/shmem.c 2015-02-20 19:33:46.116050724 -0800
@@ -6,8 +6,8 @@
* 2000-2001 Christoph Rohland
* 2000-2001 SAP AG
* 2002 Red Hat Inc.
- * Copyright (C) 2002-2011 Hugh Dickins.
- * Copyright (C) 2011 Google Inc.
+ * Copyright (C) 2002-2015 Hugh Dickins.
+ * Copyright (C) 2011-2015 Google Inc.
* Copyright (C) 2002-2005 VERITAS Software Corporation.
* Copyright (C) 2004 Andi Kleen, SuSE Labs
*
@@ -99,7 +99,6 @@ struct shmem_falloc {
enum sgp_type {
SGP_READ, /* don't exceed i_size, don't allocate page */
SGP_CACHE, /* don't exceed i_size, may allocate page */
- SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */
SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
};
@@ -167,7 +166,7 @@ static inline int shmem_reacct_size(unsi
/*
* ... whereas tmpfs objects are accounted incrementally as
- * pages are allocated, in order to allow huge sparse files.
+ * pages are allocated, in order to allow large sparse files.
* shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
* so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
*/
@@ -849,8 +848,7 @@ redirty:
return 0;
}
-#ifdef CONFIG_NUMA
-#ifdef CONFIG_TMPFS
+#if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS)
static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
{
char buffer[64];
@@ -874,7 +872,18 @@ static struct mempolicy *shmem_get_sbmpo
}
return mpol;
}
-#endif /* CONFIG_TMPFS */
+#else /* !CONFIG_NUMA || !CONFIG_TMPFS */
+static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
+{
+}
+static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
+{
+ return NULL;
+}
+#endif /* CONFIG_NUMA && CONFIG_TMPFS */
+#ifndef CONFIG_NUMA
+#define vm_policy vm_private_data
+#endif
static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
struct shmem_inode_info *info, pgoff_t index)
@@ -910,39 +919,17 @@ static struct page *shmem_alloc_page(gfp
pvma.vm_ops = NULL;
pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index);
- page = alloc_page_vma(gfp, &pvma, 0);
+ page = alloc_pages_vma(gfp, 0, &pvma, 0, numa_node_id());
+ if (page) {
+ __set_page_locked(page);
+ __SetPageSwapBacked(page);
+ }
/* Drop reference taken by mpol_shared_policy_lookup() */
mpol_cond_put(pvma.vm_policy);
return page;
}
-#else /* !CONFIG_NUMA */
-#ifdef CONFIG_TMPFS
-static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
-{
-}
-#endif /* CONFIG_TMPFS */
-
-static inline struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
- struct shmem_inode_info *info, pgoff_t index)
-{
- return swapin_readahead(swap, gfp, NULL, 0);
-}
-
-static inline struct page *shmem_alloc_page(gfp_t gfp,
- struct shmem_inode_info *info, pgoff_t index)
-{
- return alloc_page(gfp);
-}
-#endif /* CONFIG_NUMA */
-
-#if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS)
-static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
-{
- return NULL;
-}
-#endif
/*
* When a page is moved from swapcache to shmem filecache (either by the
@@ -986,8 +973,6 @@ static int shmem_replace_page(struct pag
copy_highpage(newpage, oldpage);
flush_dcache_page(newpage);
- __set_page_locked(newpage);
- __SetPageSwapBacked(newpage);
SetPageUptodate(newpage);
set_page_private(newpage, swap_index);
SetPageSwapCache(newpage);
@@ -1177,11 +1162,6 @@ repeat:
goto decused;
}
- __set_page_locked(page);
- __SetPageSwapBacked(page);
- if (sgp == SGP_WRITE)
- __SetPageReferenced(page);
-
error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg);
if (error)
goto decused;
@@ -1205,6 +1185,8 @@ repeat:
spin_unlock(&info->lock);
alloced = true;
+ if (sgp == SGP_WRITE)
+ __SetPageReferenced(page);
/*
* Let SGP_FALLOC use the SGP_WRITE optimization on a new page.
*/
@@ -1221,8 +1203,6 @@ clear:
flush_dcache_page(page);
SetPageUptodate(page);
}
- if (sgp == SGP_DIRTY)
- set_page_dirty(page);
}
/* Perhaps the file has been truncated since we checked */
@@ -1537,7 +1517,7 @@ static ssize_t shmem_file_read_iter(stru
* and even mark them dirty, so it cannot exceed the max_blocks limit.
*/
if (!iter_is_iovec(to))
- sgp = SGP_DIRTY;
+ sgp = SGP_CACHE;
index = *ppos >> PAGE_CACHE_SHIFT;
offset = *ppos & ~PAGE_CACHE_MASK;
@@ -1563,8 +1543,11 @@ static ssize_t shmem_file_read_iter(stru
error = 0;
break;
}
- if (page)
+ if (page) {
+ if (sgp == SGP_CACHE)
+ set_page_dirty(page);
unlock_page(page);
+ }
/*
* We must evaluate after, since reads (unlike writes)
--
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