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Date: Wed, 27 Jan 2010 08:09:55 -0800 (PST)
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: Chris Wilson <chris@...is-wilson.co.uk>
cc: Pekka Enberg <penberg@...helsinki.fi>,
Roman Jarosz <kedgedev@...il.com>,
A Rojas <nqn1976list@...il.com>,
"A. Boulan" <arnaud.boulan@...ertysurf.fr>, michael@...nelt.co.at,
jcnengel@...glemail.com, rientjes@...gle.com, earny@...4u.de,
linux-kernel@...r.kernel.org, intel-gfx@...ts.freedesktop.org,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
Hugh Dickins <hugh.dickins@...cali.co.uk>,
Jesse Barnes <jbarnes@...tuousgeek.org>,
Eric Anholt <eric@...olt.net>, stable@...nel.org
Subject: Re: [PATCH] drm/i915: Selectively enable self-reclaim
On Wed, 27 Jan 2010, Chris Wilson wrote:
>
> v2: Pass gfp into page mapping.
Ahh, you did need the whole complexity of ->readpage?
Ok, in that case, can you test if this works for you?
It adds a 'read_cache_page_gfp()' function, which is a simplified form of
read_cache_page() (no need to pass in filler/data, it uses the default
values, like read_mapping_page() does), but allows setting gfp explicitly.
Untested, but if you test it and it works for you, then I think it's a
reasonable addition. There might be other cases where some users prefer
certain flags.
The actual new function is just a single line, the real patch is changing
(and splitting up) the helper functions a bit so that all the variations
on read_cache_page_*() can all be trivial.
Linus
---
include/linux/pagemap.h | 2 +
mm/filemap.c | 100 ++++++++++++++++++++++++++++++++---------------
2 files changed, 70 insertions(+), 32 deletions(-)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index ed5d750..3c62ed4 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -253,6 +253,8 @@ extern struct page * read_cache_page_async(struct address_space *mapping,
extern struct page * read_cache_page(struct address_space *mapping,
pgoff_t index, filler_t *filler,
void *data);
+extern struct page * read_cache_page_gfp(struct address_space *mapping,
+ pgoff_t index, gfp_t gfp_mask);
extern int read_cache_pages(struct address_space *mapping,
struct list_head *pages, filler_t *filler, void *data);
diff --git a/mm/filemap.c b/mm/filemap.c
index 96ac6b0..e373692 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1634,14 +1634,15 @@ EXPORT_SYMBOL(generic_file_readonly_mmap);
static struct page *__read_cache_page(struct address_space *mapping,
pgoff_t index,
int (*filler)(void *,struct page*),
- void *data)
+ void *data,
+ gfp_t gfp)
{
struct page *page;
int err;
repeat:
page = find_get_page(mapping, index);
if (!page) {
- page = page_cache_alloc_cold(mapping);
+ page = __page_cache_alloc(gfp | __GFP_COLD);
if (!page)
return ERR_PTR(-ENOMEM);
err = add_to_page_cache_lru(page, mapping, index, GFP_KERNEL);
@@ -1661,31 +1662,18 @@ repeat:
return page;
}
-/**
- * read_cache_page_async - read into page cache, fill it if needed
- * @mapping: the page's address_space
- * @index: the page index
- * @filler: function to perform the read
- * @data: destination for read data
- *
- * Same as read_cache_page, but don't wait for page to become unlocked
- * after submitting it to the filler.
- *
- * Read into the page cache. If a page already exists, and PageUptodate() is
- * not set, try to fill the page but don't wait for it to become unlocked.
- *
- * If the page does not get brought uptodate, return -EIO.
- */
-struct page *read_cache_page_async(struct address_space *mapping,
+static struct page *do_read_cache_page(struct address_space *mapping,
pgoff_t index,
int (*filler)(void *,struct page*),
- void *data)
+ void *data,
+ gfp_t gfp)
+
{
struct page *page;
int err;
retry:
- page = __read_cache_page(mapping, index, filler, data);
+ page = __read_cache_page(mapping, index, filler, data, gfp);
if (IS_ERR(page))
return page;
if (PageUptodate(page))
@@ -1710,8 +1698,67 @@ out:
mark_page_accessed(page);
return page;
}
+
+/**
+ * read_cache_page_async - read into page cache, fill it if needed
+ * @mapping: the page's address_space
+ * @index: the page index
+ * @filler: function to perform the read
+ * @data: destination for read data
+ *
+ * Same as read_cache_page, but don't wait for page to become unlocked
+ * after submitting it to the filler.
+ *
+ * Read into the page cache. If a page already exists, and PageUptodate() is
+ * not set, try to fill the page but don't wait for it to become unlocked.
+ *
+ * If the page does not get brought uptodate, return -EIO.
+ */
+struct page *read_cache_page_async(struct address_space *mapping,
+ pgoff_t index,
+ int (*filler)(void *,struct page*),
+ void *data)
+{
+ return do_read_cache_page(mapping, index, filler, data, mapping_gfp_mask(mapping));
+}
EXPORT_SYMBOL(read_cache_page_async);
+static struct page *wait_on_page_read(struct page *page)
+{
+ if (!IS_ERR(page)) {
+ wait_on_page_locked(page);
+ if (!PageUptodate(page)) {
+ page_cache_release(page);
+ page = ERR_PTR(-EIO);
+ }
+ }
+ return page;
+}
+
+/**
+ * read_cache_page_gfp - read into page cache, using specified page allocation flags.
+ * @mapping: the page's address_space
+ * @index: the page index
+ * @gfp: the page allocator flags to use if allocating
+ *
+ * This is the same as "read_mapping_page(mapping, index, NULL)", but with
+ * any new page allocations done using the specified allocation flags. Note
+ * that the Radix tree operations will still use GFP_KERNEL, so you can't
+ * expect to do this atomically or anything like that - but you can pass in
+ * other page requirements.
+ *
+ * If the page does not get brought uptodate, return -EIO.
+ */
+struct page *read_cache_page_gfp(struct address_space *mapping,
+ pgoff_t index,
+ gfp_t gfp)
+{
+ filler_t *filler = (filler_t *)mapping->a_ops->readpage;
+
+ return wait_on_page_read(do_read_cache_page(mapping, index, filler, NULL, gfp));
+}
+EXPORT_SYMBOL(read_cache_page_gfp);
+
/**
* read_cache_page - read into page cache, fill it if needed
* @mapping: the page's address_space
@@ -1729,18 +1776,7 @@ struct page *read_cache_page(struct address_space *mapping,
int (*filler)(void *,struct page*),
void *data)
{
- struct page *page;
-
- page = read_cache_page_async(mapping, index, filler, data);
- if (IS_ERR(page))
- goto out;
- wait_on_page_locked(page);
- if (!PageUptodate(page)) {
- page_cache_release(page);
- page = ERR_PTR(-EIO);
- }
- out:
- return page;
+ return wait_on_page_read(read_cache_page_async(mapping, index, filler, data));
}
EXPORT_SYMBOL(read_cache_page);
--
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