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Message-ID: <20131021214735.GI29870@hippobay.mtv.corp.google.com>
Date: Mon, 21 Oct 2013 14:47:35 -0700
From: Ning Qu <quning@...gle.com>
To: Andrea Arcangeli <aarcange@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Hugh Dickins <hughd@...gle.com>
Cc: Al Viro <viro@...iv.linux.org.uk>, Hugh Dickins <hughd@...gle.com>,
Wu Fengguang <fengguang.wu@...el.com>, Jan Kara <jack@...e.cz>,
Mel Gorman <mgorman@...e.de>, linux-mm@...ck.org,
Andi Kleen <ak@...ux.intel.com>,
Matthew Wilcox <willy@...ux.intel.com>,
Hillf Danton <dhillf@...il.com>, Dave Hansen <dave@...1.net>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
Ning Qu <quning@...gle.com>, Ning Qu <quning@...il.com>
Subject: [PATCHv2 08/13] mm, thp, tmpfs: handle huge page in shmem_undo_range
for truncate
When comes to truncate file, add support to handle huge page in the
truncate range.
Signed-off-by: Ning Qu <quning@...il.com>
---
mm/shmem.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 74 insertions(+), 11 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index af56731..f6829fd 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -526,6 +526,7 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
struct shmem_inode_info *info = SHMEM_I(inode);
pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
pgoff_t end = (lend + 1) >> PAGE_CACHE_SHIFT;
+ /* Whether we have to do partial truncate */
unsigned int partial_start = lstart & (PAGE_CACHE_SIZE - 1);
unsigned int partial_end = (lend + 1) & (PAGE_CACHE_SIZE - 1);
struct pagevec pvec;
@@ -537,12 +538,16 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
if (lend == -1)
end = -1; /* unsigned, so actually very big */
+ i_split_down_read(inode);
pagevec_init(&pvec, 0);
index = start;
while (index < end) {
+ bool thp = false;
+
pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE),
pvec.pages, indices);
+
if (!pvec.nr)
break;
mem_cgroup_uncharge_start();
@@ -553,6 +558,23 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
if (index >= end)
break;
+ thp = PageTransHugeCache(page);
+ if (thp) {
+ /* the range starts in middle of huge page */
+ if (index < start) {
+ partial_start = true;
+ start = index + HPAGE_CACHE_NR;
+ break;
+ }
+
+ /* the range ends on huge page */
+ if (index == (end & ~HPAGE_CACHE_INDEX_MASK)) {
+ partial_end = true;
+ end = index;
+ break;
+ }
+ }
+
if (radix_tree_exceptional_entry(page)) {
if (unfalloc)
continue;
@@ -570,26 +592,47 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
}
}
unlock_page(page);
+ if (thp)
+ break;
}
shmem_deswap_pagevec(&pvec);
pagevec_release(&pvec);
mem_cgroup_uncharge_end();
cond_resched();
- index++;
+ if (thp)
+ index += HPAGE_CACHE_NR;
+ else
+ index++;
}
if (partial_start) {
struct page *page = NULL;
gfp_t gfp = mapping_gfp_mask(inode->i_mapping);
+ int flags = AOP_FLAG_TRANSHUGE;
- shmem_getpage(inode, start - 1, &page, SGP_READ, gfp, 0, NULL);
+ shmem_getpage(inode, start - 1, &page, SGP_READ, gfp,
+ flags, NULL);
if (page) {
- unsigned int top = PAGE_CACHE_SIZE;
- if (start > end) {
- top = partial_end;
- partial_end = 0;
+ pgoff_t index_mask;
+ loff_t page_cache_mask;
+ unsigned pstart, pend;
+
+ index_mask = 0UL;
+ page_cache_mask = PAGE_CACHE_MASK;
+ if (PageTransHugeCache(page)) {
+ index_mask = HPAGE_CACHE_INDEX_MASK;
+ page_cache_mask = HPAGE_PMD_MASK;
}
- zero_user_segment(page, partial_start, top);
+
+ pstart = lstart & ~page_cache_mask;
+ if ((end & ~index_mask) == page->index) {
+ pend = (lend + 1) & ~page_cache_mask;
+ end = page->index;
+ partial_end = false; /* handled here */
+ } else
+ pend = PAGE_CACHE_SIZE << compound_order(page);
+
+ zero_pagecache_segment(page, pstart, pend);
set_page_dirty(page);
unlock_page(page);
page_cache_release(page);
@@ -598,20 +641,32 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
if (partial_end) {
struct page *page = NULL;
gfp_t gfp = mapping_gfp_mask(inode->i_mapping);
+ int flags = AOP_FLAG_TRANSHUGE;
- shmem_getpage(inode, end, &page, SGP_READ, gfp, 0, NULL);
+ shmem_getpage(inode, end, &page, SGP_READ, gfp,
+ flags, NULL);
if (page) {
- zero_user_segment(page, 0, partial_end);
+ loff_t page_cache_mask;
+ unsigned pend;
+
+ page_cache_mask = PAGE_CACHE_MASK;
+ if (PageTransHugeCache(page))
+ page_cache_mask = HPAGE_PMD_MASK;
+ pend = (lend + 1) & ~page_cache_mask;
+ end = page->index;
+ zero_pagecache_segment(page, 0, pend);
set_page_dirty(page);
unlock_page(page);
page_cache_release(page);
}
}
if (start >= end)
- return;
+ goto out;
index = start;
for ( ; ; ) {
+ bool thp = false;
+
cond_resched();
pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE),
@@ -643,6 +698,7 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
continue;
}
+ thp = PageTransHugeCache(page);
lock_page(page);
if (!unfalloc || !PageUptodate(page)) {
if (page->mapping == mapping) {
@@ -651,17 +707,24 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
}
}
unlock_page(page);
+ if (thp)
+ break;
}
shmem_deswap_pagevec(&pvec);
pagevec_release(&pvec);
mem_cgroup_uncharge_end();
- index++;
+ if (thp)
+ index += HPAGE_CACHE_NR;
+ else
+ index++;
}
spin_lock(&info->lock);
info->swapped -= nr_swaps_freed;
shmem_recalc_inode(inode);
spin_unlock(&info->lock);
+out:
+ i_split_up_read(inode);
}
void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
--
1.8.4
--
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