Hi Linus,
Finally shm swapping seems to work for me again. The following patch
fixes a refcounting bug which got introduced with 2.3.11. (Thanks to
Manfred who finally found the right point). It survived a lot of swap
stress testing on UP/32MB up to 8xSMP/8GB.
The patch also fixes some int/size_t issues.
Could you please apply this.
Greetings
Christoph
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--- 2.3.27-pre6/ipc/shm.c Thu Nov 11 10:33:16 1999
+++ make27/ipc/shm.c Thu Nov 11 14:47:57 1999
@@ -206,7 +206,7 @@
struct shmid_kernel *shp;
int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
int id, err;
- unsigned int shmall, shmmni;
+ size_t shmall, shmmni;
shmall = shm_prm[1];
shmmni = shm_prm[2];
@@ -378,13 +378,16 @@
case IPC_INFO:
{
struct shminfo shminfo;
+ size_t shmmax;
+
spin_unlock(&shm_lock);
err = -EFAULT;
if (!buf)
goto out;
+ shmmax=shm_prm[0];
+ shminfo.shmmax = shmmax > UINT_MAX ? UINT_MAX : shmmax;
shminfo.shmmni = shminfo.shmseg = shm_prm[2];
- shminfo.shmmax = shm_prm[0];
shminfo.shmall = shm_prm[1];
shminfo.shmmin = SHMMIN;
@@ -791,11 +794,14 @@
if (!page) {
lock_kernel();
swapin_readahead(entry);
+ if (pte_val(pte) != pte_val(SHM_ENTRY(shp, idx))) goto again;
page = read_swap_cache(entry);
unlock_kernel();
if (!page)
goto oom;
}
+ if (pte_val(pte) != pte_val(SHM_ENTRY(shp, idx)))
+ goto changed;
delete_from_swap_cache(page);
page = replace_with_highmem(page);
lock_kernel();
@@ -803,9 +809,6 @@
unlock_kernel();
spin_lock(&shm_lock);
shm_swp--;
- pte = SHM_ENTRY(shp, idx);
- if (pte_present(pte))
- goto present;
}
shm_rss++;
pte = pte_mkdirty(mk_pte(page, PAGE_SHARED));
@@ -813,8 +816,6 @@
} else
--current->maj_flt; /* was incremented in do_no_page */
-done:
- /* pte_val(pte) == SHM_ENTRY (shp, idx) */
get_page(pte_page(pte));
spin_unlock(&shm_lock);
current->min_flt++;
@@ -823,10 +824,6 @@
changed:
__free_page(page);
goto again;
-present:
- if (page)
- free_page_and_swap_cache(page);
- goto done;
oom:
return NOPAGE_OOM;
}
--Multipart_Thu_Nov_11_16:43:08_1999-1--
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